Some engineers use grads, which divide a right angle into 100, and maths often uses radians, of which there are 2Pi in a circle.
EDIT: Many people have rightly pointed out that suggesting radians are arbitrary is wrong. Yes - you're right - it's part of fundamentals of the universe.
Edit: Thank you for the Gold, my gilded cherry has been popped.
Doomur17 · 3948 points · Posted at 09:25:22 on January 9, 2016 · (Permalink)
Halfway through my 3rd year of engineering school, it just clicked.
lucasvb · 5926 points · Posted at 11:53:40 on January 9, 2016 · (Permalink)*
I'm the author of the GIF. It's comments like this that make doing these animations worth it. :')
Thanks!
EDIT: Check my Wikipedia gallery and my Tumblr for more of my math/physics GIFs. I'm also working on a YouTube channel where I'll post some accessible, but more technical, explanations of math and physics topics in a few months.
Do you have any more? Honestly, an album of stuff like this would keep me occupied for... well, depends how long the album is... but multiple mind-blowings would be like a mathematical orgy, if you can provide them.
xueimel · 961 points · Posted at 13:20:30 on January 9, 2016 · (Permalink)
not sure if relevant to your interests, but there's this.
There's a fertility clinic near me called ISIS something something, and the sign just had ISIS in huge letters with the something something in small print beneath it. Kinda unfortunate.
[deleted] · 1 points · Posted at 20:43:59 on January 9, 2016 · (Permalink)
Wear it anyways. I would.
Cypraea · 7 points · Posted at 19:26:35 on January 9, 2016 · (Permalink)
I went to high school with a girl named Isis. There are actual people with that name, that this is fucking up. It's like hurricanes (I have an Aunt Katrina), but worse.
Daesh is the derogatory name in Arabic for the Islamic state. Fuck daesh.
MTL_Bob · 2 points · Posted at 15:37:46 on January 9, 2016 · (Permalink)
Agreed
That's why I tell everyone that will listen not to call them Isis, call them "Daesh" it's what everyone on the ground fighting (Pashmerga etc) refers to them as and they hate it (it is apparently very derogatory)
[deleted] · 2 points · Posted at 15:49:17 on January 9, 2016 · (Permalink)
Daesh, it is. I wonder if we could make a reddit post popular enough to make the media take notice and start using that as the defacto, popular term.
MTL_Bob · 3 points · Posted at 16:02:25 on January 9, 2016 · (Permalink)
It's actually kind of odd.. From my experience, only English media is still using Isis.. Any Arabic outlet uses Daesh.. And French switched to it after the Charlie Hebdo attack last year.. Would definitely be nice to see the undeniably influential American media also make the switch..
I like to explain it like this: do we refer to Kim Jung Un as "Dear Supreme Leader" just because he's decided that's his title? Or do we call North Korea "the Democratic Peoples Korean Republic"? No.. Because neither is a representative name..
At least they kept the dog in the intro. It wouldn't be the same show without seeing her partially exposed butthole when that tail clockworks to the extreme left.
don't let them into real life and civilization because they chose that name
They didn't choose it. The media chose it and continues to choose to use it. The name of the actual organization of murderous jackasses is not in English and doesn't use the Roman alphabet.
Personally, I call them "ISIL" which is just as valid and doesn't defame "Isis."
[deleted] · 1 points · Posted at 17:55:56 on January 9, 2016 · (Permalink)
Is that why President Obama refers to them as ISIL?
I could watch that animation for hours. I wish I had it when I was in school, maybe I wouldn't have flunked out. (I'm all seriousness a whack of math came flooding in when I saw this). Cheers
I learned calculus in high school. Math up to that point was easy. It all just kind of made sense. But calculus didn't click. So I lost interest and my grades suffered because I didn't try anymore. It wasn't until almost 10 years later helping my little brother with a finance or business management course that I saw a problem and my mind went "This is calculus!!!" I understand everything now.
Makes me want to get out my old calc textbook and learn it all over again.
It was related rates that got me, the examples were shit and didn't clearly explain the use of it.
meladon · 1 points · Posted at 15:22:59 on January 9, 2016 · (Permalink)
Do you have any more? Honestly an album full of reddit comments would keep me occupied for... well, depends how long the album is... but multiple mind-blowings would be like a reddit comment orgy, if you can provide them.
Do you have any more? Honestly, a page of comments like this would keep me occupied for... well, depends how long the page is... but multiple mind-blowings would be like a reddit orgy, if you can provide them.
Do you have any more? Honestly, an album of comments like this would keep me occupied for... well, depends how long the album is... but multiple mind-chucklings would be like a literary orgy, if you can provide them.
[deleted] · 1 points · Posted at 18:51:27 on January 9, 2016 · (Permalink)
swohio · 9 points · Posted at 16:56:20 on January 9, 2016 · (Permalink)
I think the best way to describe it is be drawing a sine wave on a flat piece of paper, then rolling the paper into a cylinder. If you run your finger along the drawn sine wave, it now gives the motion of a circular orbit. This demonstrates how the 3D orbit results in a sine wave on a 2D map.
When I couldn't remember the name of common core I just googled "new math" and came across that. Jesus Christ that was fucked. My favourite part of the article was a quip from the Simpsons.
Principal Skinner is elated, and muses about all of the improvements to the elementary school they can obtain with the new funding, such as history books that reveal how the Korean War ended, and "math books that don't have that base six crap in them!"
Say you move around a circle with it's centre at the origin, at constant speed. At any point you will be at be a certain height above above or below the 0 line (x axis). BY DEFINITION the sine of the angle to where you are on the circle is defined as the Opposite / Hypoteneuse. Since you are on a circle the hypotenuse is always the same distance - the radius (ie from the centre to the circumference), but the height is changing - or the opposite. Therefore it is possible you can say two are sort of equivalent. Ie. the height changes thew same sine of the angle the height is at.
So as you go along the circle you can plot the height at any time along another graph. If you plot the sin of the angle cast on the same graph it will be exactly the same.
Tldr; It comes from the definition of what sine is.
Hope that helps. I'm not a mathematician and I last did this stuff at uni in the 80s, but it has always helps me to visualise moving pictures. You guys have gifs and videos - we had to use our imaginations.
That, along with this which I had a bit of a read through earlier have definitely helped me get a better grasp. After everything your tldr is pretty much the why I was after, even though it ends up being somewhat cyclical (excuse the pun). Thanks very much for your help!
[deleted] · 3 points · Posted at 13:47:08 on January 9, 2016 · (Permalink)
[deleted] · 1 points · Posted at 16:04:01 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 1 points · Posted at 16:58:49 on January 9, 2016 · (Permalink)
Not sure much about electrical engineering, but I know there is a specific equation that transforms a sine wave into a square wave, or it at least converges to it. I'll try to find try later but I'm on mobile.
apcragg · 1 points · Posted at 00:43:41 on January 10, 2016 · (Permalink)
The Fourier series of a 50% duty cycle square wave is the sum over every odd harmonic diminished by a factor of 1/n where n is the harmonic number.
[deleted] · 1 points · Posted at 00:50:26 on January 10, 2016 · (Permalink)
Smoothed DC is a line, not a square wave at all, youre thinking about digital as opposed to analog. Without any smoothing a half-wave rectification of AC would look like a sine wave without the bottom half, as you say the troughs are at the x axis. Full wave rectification is what you want though, and this just flips the bottom part of the wave up to its same position along the x axis, making the top part of the waves overlap
Qazdthm · 1 points · Posted at 15:53:49 on January 9, 2016 · (Permalink)
For the record the circle on the left can be called a phase and is used to easily depict everything from AC current and voltage in different circuits to EM waves
I watched the Cylindrical coordinates gif and it made them look horribly hard. Isn't it easier to just say that you can write a point as radius and angle?
Apolik · 28 points · Posted at 15:18:42 on January 9, 2016 · (Permalink)
That's because the animation is about the transformation from cartesian to polar. Not about "just" polar coordinates.
ohSpite · 3 points · Posted at 14:40:50 on January 9, 2016 · (Permalink)
I've only just started covering them so I may be wrong but that's essentially whats being done, where the distance from the origin (pole) is defined as a function in terms of the angle created ACW with respect to the positive x axis (incident line)
[deleted] · 4 points · Posted at 15:19:28 on January 9, 2016 · (Permalink)
No, it's brilliant. Made it click for me. I'm really good with 3D and spacial reasoning and the gif makes it very clear what's happening, for me at least.
Conversely, I'm terrible at visualizing things, and that gif finally made it click what the "real" connection between Cartesian and polar coordinates is. I could do the math, but I was always at a loss for what they had to do with one another in a real-world sense.
From everything I remember about cylindrical coordinates, they are horribly hard. The maths isn't particularly complex or anything, but everyone in my class found them an absolute pain for some reason. It may well be that the subject is just taught badly.
to be fair it's usually a very early or even first introduction to alternate coordinate systems, which can be a hard concept for people who have been cartesians for their whole academic career
Radius and angle work fine for two dimensions, but thinking about it, that isn't enough to describe a location in 3 dimensions. You can use spherical coordinates which gives you a radius, and 2 angles, so you know how far it is from the origin, and its angle with respect to two of the coordinate axes, which is enough info to get its location. Cylindrical coordinates rely on a radius, height, and angle. Radius denotes how far the point is with respect to one coordinate plane, the angle describes its location in said plain, and then the height describes its position with respect to the third axis. I think polar is fine for two dimensions, but when you get to 3, I much prefer rectangular.
lucasvb · 50 points · Posted at 13:43:43 on January 9, 2016 · (Permalink)*
I've only published half of the stuff I ever did. Most didn't work as well as I hoped and were too "wild" to belong on Wikipedia. I don't know if I have the source of all of them anymore.
[deleted] · 18 points · Posted at 14:05:53 on January 9, 2016 · (Permalink)*
[deleted]
lucasvb · 34 points · Posted at 14:08:28 on January 9, 2016 · (Permalink)*
Once I'm back to my apartment where my old files are I'll see what I can find and post to my Tumblr. I wrote your username down to notify you.
You can also just subscribe to the RSS feed if you want to keep up with my updates.
I've seen so many of your gifs while looking up things for my various math classes. Your gif of the gram-schmit process was incredibly helpful. Thanks so much man
[deleted] · 1 points · Posted at 22:49:53 on January 9, 2016 · (Permalink)
RemindMe! 1 month
bieker · 2 points · Posted at 15:47:09 on January 9, 2016 · (Permalink)
Some of the coolest graphics of this type I've seen were on NASAs website and were about orbital mechanics. Showing things like how the velocity changes in elliptical orbits so that the area swept by a line connecting the satellite and the nearest focus is always the same for equal periods of time.
I've never been able to find them again. Have you ever done any like that?
lucasvb · 1 points · Posted at 15:50:05 on January 9, 2016 · (Permalink)
That's Kepler's 2nd Law. There's a few animations of this around, just search for it.
mlmayo · 1 points · Posted at 14:36:27 on January 9, 2016 · (Permalink)
Do you care if they are videos or must they be GIFs? There are competitions for mathematics visualizations. For example, there's the Vizzies. One winner I really liked was about Mobius Transformations, of all things.
Looks like you made this one as well? Really helped me understand Fourier transforms.
lucasvb · 121 points · Posted at 13:18:40 on January 9, 2016 · (Permalink)
Yeah. That one was aiming at explaining time/frequency domains. Fourier transforms have been my nemesis. I never found a good way to illustrate them.
Most illustrations show only that they work ("here are some magical frequencies. Look what happens when we add these waves!"), not why/how they work. The transform is about extracting the "weight" of each frequency, after all.
I think I found a GREAT way to explain it which goes through linear algebra. But I'll need to make a video with narration and an interactive page. That'll be coming in the near future.
For anyone who wants to learn more, I think that what really made them click for me was watching a web series on those Harmonic Analyzers that did these calculations manually. This series from the engineer guy (https://www.youtube.com/watch?v=NAsM30MAHLg) is absolutely fantastic.
15 years ago or so I wrote a wikipedia article. A small, puny one, about a book. And it was a TON of work.
Since then, guys that contribute to WP in any way are my heroes. But you specifically are simply put, the hero of heroes. You really go way beyond of what is expected of reference material and cross the line into actually educational, which is rare even for very expensive material, not to mention free.
Also, your way of mathing speaks to me. Thank you from the bottom of my heart. I have trouble expressing how awesome you are for contributing to WP in the way you are.
lucasvb · 1 points · Posted at 19:19:12 on January 9, 2016 · (Permalink)
Thank you for the kind words!
The way I see it, I'm not really contributing to Wikipedia. I'm contributing to everyone. Wikipedia just happens to be a good vehicle for that. :)
This is why I always release these animations in the public domain, and try to make them language-agnostic. I just want people to have them. All the people.
I do wish I could get proper credit when people repost them around, because hey, I put a lot of effort in these. But getting credit is insignificant compared to the value of thousands of people learning about math. That's why I do this.
Do you have a subreddit or site where people can dig into this? I've always excelled at geometry because I think with the logic and visual/spatial relationships very well, but the formulaic approach killed me for algebra and calc etc. these are brilliant for me to understand all the "Greek" in math in a way that related to things I understand.
Thank you!!!
lucasvb · 2 points · Posted at 14:28:21 on January 9, 2016 · (Permalink)
Not yet. I have a few stuff in my Tumblr, but it's not super in-depth.
I've been working on a YouTube channel where I'll explain a lot of math and physics stuff with more depth, but still in an accessible way. The technical animations I make will be of great help here. I'm dropping the link now so you guys can subscribe and get the video later, once I start uploading.
Some of the YouTube videos will also have a blog post and maybe interactive applets associated with them, since I think a lot of these concepts will need that kind of interaction to really sink in. You'll know about it when these videos come out.
[deleted] · 2 points · Posted at 14:32:19 on January 9, 2016 · (Permalink)
INSTANT SUBSCRIPTION
Might be very interesting and helpful for me. Thank you for your work!
I'm looking forward to this, as your gif cleared up a lot of confusion I had in the beginning about FT. I've developed some neat intuitions about how the transform actually works, and I can see how it would be difficult to actually present something visual without making a mess.
Actually going this deep isn't required to pass my courses, but I feel like it pays off both in pure intuition and in being awe struck by how clever we humans actually are.
Your gifs have helped me develop this intuition, so I thank you and look forward to seing content on your youtube channel :-)
Try watching this series on harmonic analyzers, the machines that were created to perform these calculations manually. I feel it really made them click for me: https://www.youtube.com/watch?v=NAsM30MAHLg
I always had trouble with geometry because I needed visualizations to learn and everyone's attitude when I was in school was "just plug the numbers into the formulas". So thank you for making this gif. (There weren't gifs when I was in school, haha) I finally get to have something geometry related click after 20+ years and it makes me happy. Thank you :)
lucasvb · 297 points · Posted at 13:21:07 on January 9, 2016 · (Permalink)
You're not the only one having issues, our system is broken. It's one of my long term goals in life to do whatever I can to fix math and physics education by making use of modern technology. Hopefully in a way that's public domain and easily translatable to other languages.
We could be doing so much more to teach these concepts with clarity. These animations are just a tiny contribution to the effort I can make right now.
Thanks for the kind words. :)
[deleted] · 44 points · Posted at 13:50:42 on January 9, 2016 · (Permalink)
I had an amazing geometry teacher who had a real passion for helping people understand geometry -- he drew almost that exact same thing on the board, and explained it the same way. He died a few years back, so this makes me smile... Thanks for making it.
lucasvb · 19 points · Posted at 14:06:16 on January 9, 2016 · (Permalink)
Khan Academy is pretty darn good for instructional videos. Definitely not perfect, but if you get stuck on something then there's a huge forum of peoples questions and answers.
According to my high school math teaching cousin, she would love it if her students even cared enough to cheat on their homework by using wolframalpha or sth. But the "bad" students are the ones giving zero effort. And the students doing poorly that want to do better? Her biggest recommendation to their parents is to make flash cards and memorize their times tables. That's how broken or system is.
user__3 · 1 points · Posted at 18:50:21 on January 9, 2016 · (Permalink)
I'll be going to junior college for the first time in a couple of weeks and I'm taking a math class; I really hope my teacher will actually care to explain the math instead of just telling the students to read the textbook and memorize formulas.
I'm sure it depends on the school but I haven't had an instructor yet that wasn't super interested and passionate about their subject (I'm at a jc as well).
Thank you for your work. I too lost interest in mathematics when a teacher failed to explain how and why something worked and told me just to memorize the formula. Visualizations and logical explanations will go a long way to fixing that type of issue.
akuthia · 2 points · Posted at 20:07:13 on January 9, 2016 · (Permalink)
Which is damn sad because at some point math becomes not about equations but about logic. I can't tell you where because despite having aptitude in math up through algebra 3/trig in high school when I tried to restart my life with mathematics I stumbled at calc 1
The college-level calc series is largely an extension of the high-school algebra.
There are a million million sub-disciplines like logic, modern algebra, combinatorics, graph theory, topology, number theory, etc that are very different than what we're used to (and had ruined for us) in the public education system.
It's all about proving things based on prior assumptions with logical rules (maybe a generalization but eh)
Has our system always been broken? I don't mean a specific national education system, I mean the way math has always been taught. Was there some way in the past that math was taught better than now? One thing I especially liked about some math teachers I had was when they talked about the people that came up with the math. I had to google the name, but one that stood out was Galois, in my linear algebra class. He had done amazing things and died at an age where a lot of people are still considered children today.
How did he learn math? Are people like him flukes, and genius beyond my capability? I really feel like I'm too dumb for math. I don't lose sleep over it. The universal response to this when I tell people about my feeling, is that 'anyone can learn anything,' or 'I just needed to try harder.' I feel like that's a feel-good answer, and I don't believe it. Could I learn like Galois? Is it the system that failed me? Or did I just not try hard enough? Or can I just not be that smart in math?
Chii · 2 points · Posted at 19:16:36 on January 9, 2016 · (Permalink)
feynman explained in the vid that ways of thinking, for even something as simple as counting numbers, is actually vastly different between different people. So when somebody doesn't understand something, it's usually because their "internal" model is somehow incompatible with the way it's being explained to them, not that they are dumb. A genius might actually just be an accident where their internal model happens to be very well suited for a certain kind of explanation, and mode of thinking - leading them to be able to grok faster, and like compound interest, their knowledge "savings in the bank" just grows much faster than average. So to achieve the same, a person with an incompatible mental model might have to work twice, or three times as hard.
I agree with this. I have a really good internal dialogue when it comes to grasping new concepts, but I've noticed others don't seem to click the same way. I've learned that the best way to teach is to ask questions of the students in the right way to guide them to the answer instead of just giving it to them. I tutored a friend in high school for about an hour the day before his final, and he said he learned more than he had the entire year. Schools are broken, plain and simple.
I love Feynman and his brilliant explanations. I like it when he gets flustered explaining stuff. I'm gonna binge on him again. Thanks for reminding me
If you ever want some tutoring I'd gladly start a youtube/twitch channel to answer your questions! I feel like I'm a pretty good teacher and would love to make videos to help people understand math better!
lucasvb · 2 points · Posted at 17:38:58 on January 9, 2016 · (Permalink)
I think it's always been a bit obtuse. I've had the chance to pick two very old math books to check out, and the methods are pretty much the same. Hell, even some of the exercises were the same.
The general narrative of math texts is just backwards, in my opinion. So I think people who managed to thrive just have the proper upbringing and mental mindset, for whatever reasons, to understand it. Everyone struggles with something or the other. It's hard to tell what actually goes into the minds of the geniuses, and we don't really have a good idea of their background.
But making things clear and simple to understand is extremely hard, too. So there's quite a bit of inertia and regurgitation in the way of progress.
Thank you so much for your dedication to helping fix things! Because of people like you, I know my daughter will have an easier time finding alternative resources to explain complicated concepts, and she'll have a better chance to understand and learn to love math instead of dreading and loathing it. The internet wouldn't be the magical resource it is without treasures like you. Love your work and looking forward to the post of the "wild" ones in February, thanks again :)
It's not just the grade-school education system, either. I had a professor in university who, when I asked for the reasoning behind some aspect of matrix calculations (don't remember what - it was a long time ago), told me "because it's the rule. You have to do it this way or you get the wrong answer."
I struggled in that class for weeks, until a programming lab instructor had me mess with the matrix calculations for a 3D animation. If you did it wrong, you'd end up moving the object to the right instead of rotating it, or turning it inside out instead of moving it forward.
My grades in that class went from 60 to 95 in the span of 10 minutes.
lucasvb · 1 points · Posted at 16:03:20 on January 9, 2016 · (Permalink)
Yep. A lot of teachers have no idea why things are the way they are either. Hard to expect understanding from a mentor who doesn't understand things themselves.
You are seriously really great. I ended up in a field that barely uses math at all, but for quite some time have wished to relearn what I learned in school, and more. Is there a place you would recommend starting?
lucasvb · 3 points · Posted at 16:01:17 on January 9, 2016 · (Permalink)
Sadly, I don't know much in terms of recommendations.
There's little things that can be helpful here and there around the internet, but there's no single resource that goes through everything from the basics upwards in a way that I think it is outstanding. At least none I'm aware of.
What I do recommend is never giving up on a concept and "just memorizing it", because everything HAS to make sense. To achieve this, just expose yourself to as many explanations of a topic and think hard about it until something sticks. That's what I've done.
Knowing a bunch of facts doesn't necessarily make you smart. Knowing how they fit together, and being able to make useful decisions based on that, does.
I think it's sort of telling that that gif felt like cheating because I understood it so quickly, and yet struggled with math all through middle and high school. Thanks for a mini-confidence booster first thing in the morning!
juletre · 1 points · Posted at 18:37:46 on January 9, 2016 · (Permalink)
Have you sern Mathbox2 ? (Google mathbox death of powerpoint) . It talks about having animations in lectures, but eith the actual math being done and not a prerendered animation. It makes it easier to understand fractals as well.
lucasvb · 2 points · Posted at 18:38:53 on January 9, 2016 · (Permalink)
Yep. Steven Wittens and I have talked about collaborating somehow in the future.
juletre · 1 points · Posted at 22:19:23 on January 9, 2016 · (Permalink)
Cool. I'll be on the lookout for that!
blbd · 1 points · Posted at 19:05:19 on January 9, 2016 · (Permalink)
I am still waiting for project based learning to be adopted after several decades of studies repeatedly finding it better than the old way. But it will be difficult for any of these innovations to happen if we don't start taking teaching more seriously like Korea and Finland do. Right now we treat it as an expense instead of as an important investment.
poompk · 1 points · Posted at 00:23:09 on January 10, 2016 · (Permalink)
Thank you so much for doing the work you do. As a major fan of the subject, I also think the way math is taught in primary and secondary schools is horrendous and hope that we can all fix it someday. Just want to express my appreciation and hope you keep it up! :)
I don't see why these aren't used in school already. I love the simplicity of it, it's great!! This would have helped me so much when I was in school and imagine it being applied to other mathematical equations.
lucasvb · 1 points · Posted at 13:59:01 on January 9, 2016 · (Permalink)
Sadly, a lot of teachers aren't even aware of this geometric reasoning, and most people (students or teachers) don't look up stuff they are learning to get a different source/perspective.
You can't really prove things visually though. You can give a visual motivation as to why the theorem might be true but you can never prove it visually.
Personally, I can't visualize things in my head. But that doesn't mean I don't get anything out of seeing things illustrated. If anything, I might need them more in some situations since I can't just picture it myself.
But when it comes to geometry specifically, my class was 1/2 visual and 1/2 proofs, and the heavy reliance on visuals was a little irritating to me because I much prefer just sitting down and doing math (see also: revolving solids and 3D molecular drawings, because rotating things is the worst). Yet, weirdly, when I had a class in college that went through Euclid's Elements, the completely visual proofs of everything were actually pretty awesome. It's weird how simple some of them are when you break them down to just straight lines and circles.
That is a problem, but the other extreme is nearly as bad. Math education trends seem to alternate between "shut up and calculate" and "draw a map to the answer."
My time in geometry class in high school was almost all spent working with compass and straight edge. I have an OK grasp of how to visualize my way to an answer, but almost no idea how to explain or write about geometry, or proofs in general, which, along with an informal, hand-holdy (but very effective) calculus class ended up crippling my college math. I flunked discrete math three times before I finally figured out how to read a proof, and I only managed that by finding a discrete math class offered by the computer science department taught in Prolog.
It's unfortunate how teaching being "too good" in the short term can fail so badly to prepare one to learn on their own.
I truly believe too many people are not reading the book.
Reading is fundamental in our society but I think people have learned in the public education system especially that the job of a teacher is to be a tour guide, and to hold your hand and spoon feed you things a little at a time.
Reading is like exploring, in many other disciplines and in professional life you have to read read read, and explore.
Teachers are there to talk to you when you just can't make it work on your own and you need somebody to wave their arms around and chat with you.
Not to say everyone doesn't have different styles of learning, just saying all styles of learning are part of the whole of learning and they all should be practiced for highly effective learning.
You are the first person who has ever suggested reading a math textbook to me. Every math teacher I have ever had used the text only as a source of exercises. My high school calculus teacher even told me not to read it because it was "too complicated and impossible to understand." Some of my college professors even told their classes to return their books if they bought them because, although required by policy, they would never be used.
She wasn't wrong. I knew so little notation I couldn't even have read most of the lessons aloud, let alone understand them. At the time the only Greek letters I could recognize were lowercase pi and theta.
30 seconds ago I'm just a guy taking a shit. Now? I'm a guy taking a shit who knows what a mothafuckin rad is
Dabfo · 13 points · Posted at 13:16:18 on January 9, 2016 · (Permalink)
This gif should be required in math classes teaching this concept. So simple yet so often not taught correctly or at all.
lucasvb · 10 points · Posted at 13:55:19 on January 9, 2016 · (Permalink)
Yeah, it's disgraceful that this concept is so often taught without a single illustration.
Aerroon · 1 points · Posted at 14:14:26 on January 9, 2016 · (Permalink)
I don't understand - what does this tell you? I mean by the definition of radians you would understand this. And every time you convert from degrees to radians or vice versa you would use this knowledge.
Every time I have seen this animation posted I've seen people say that it suddenly clicks for them but I don't understand what they "get". I feel like I'm still missing it, because this definitely did not make me suddenly understand radians more intuitively or want to use radians more.
SGlyko · 20 points · Posted at 14:30:50 on January 9, 2016 · (Permalink)
People learn differently. You're like me - verbal descriptions are usually enough to explain a concept. You hear, "A radian is the measure of the angle such that the arc created is equal to the length of the radius" and you can essentially draw that gif in your mind. We're not all wired the same way, so some people get lost in that word-soup and are much more easily able to understand by way of an illustration. You and I may not need that illustration, but that doesn't mean we're smarter, more talented, or better than the folks that understand better with the animation - we just learn differently.
Dabfo · 9 points · Posted at 14:55:04 on January 9, 2016 · (Permalink)*
That's not it. I'm well past getting it, but I remember having high school teachers and even a fair amount if professors that teach concepts and expect students to remember them by wrote memorization instead of explaining the reasoning behind it.
I would bet money that 180 deg = 2 pi is taught more than taking the extra 5 min to explain why, as this simple gif elegantly shows.
It is the same for sinusoidal waves and lots of other concepts. I remember Fourier transforms not clicking until I started working with spectrum analyzers in the lab almost 10 years after I struggled through them in college. I walked out of that class with an "A" and no idea how to apply it because it was all memorization and knowing just enough to get by, but not enough understanding to see the beauty of the application.
Too many teachers teach just enough to move on to the next concept, not caring to show some of the simple elegance of the concepts.
Radians are not a dumb unit! Degrees are the dumb unit! Breaking things into 360 is Babylonian garbage. This way, all you have to do to find the length of a circular arc is multiply its angle in radians by the radius of the circle!
I was being slightly sarcastic. Saying ".35 radians" as an angle is a lot less obvious than using 15 degrees, since the scale of the unit doesn't natively lend itself to easy mental math.
Like saying .05 kilometers instead of 50 meters, it's the same thing, it's just one is easier to manipulate in your head because it uses integer numbers and the scale is more appropriate.
Having ~6.28 radians per circle is just an awkward number to try to subdivide, was my point, not that it doesn't have its uses.
That's true. I'm definitely biased because I come from a math background, but I can see how maybe an engineering person would find the numbers unnecessarily awkward.
I'm seriously confused how people are responding to this as if its new insight. Isn't this what they always teach when they introduce radians in school?
[deleted] · 26 points · Posted at 20:43:01 on January 9, 2016 · (Permalink)
Nope, it's just another equation to memorize when the teacher doesn't care enough to explain it
Fastco · 2 points · Posted at 22:14:36 on January 9, 2016 · (Permalink)
Yeah I can understand that in lower level classes but I mean when you have to do differential equations in polar coordinates I would think you would have a basic understanding of them? Maybe me and my friends were an exception.
Ninja Edit: Also in one of my trig classes we were taught to ALWAYS use radians, you would think people would understand what they are by working with them so much
alanwj · 3 points · Posted at 02:59:58 on January 10, 2016 · (Permalink)
I've always felt we should just call them "radiuses" instead of "radians", to drive the point home.
Fastco · 1 points · Posted at 19:15:59 on January 10, 2016 · (Permalink)
I think it is close enough as it is, besides in general its best to not name two different things the same. Radians are a unit of angle, and radiuses are the length of a specific thing. I think the biggest problem is our teaching of equations without giving the underlaying knowledge behind them.
[deleted] · 2 points · Posted at 00:23:58 on January 10, 2016 · (Permalink)
We're talking average students here, who never need to take differential equation classes in polar coordinates--I assume most people who get to that point are familiar with how radians work.
It's not that they were taught to use radians, it's just it was never explained what a radian really is.
It's like using x = -b/2a for quadratic functions--it's just an equation (but people who take calculus will be able to derive that).
Fastco · 1 points · Posted at 19:11:02 on January 10, 2016 · (Permalink)
I guess I was mainly replying to the dude who said he has a masters in Mechanical Engineering, tell me that dude didn't do a shit load of differential equations in polar coordinates. Source: former mechanical engineering student
Some people learned what it was in high school and never used it, then eventually became one of those math buzzwords they recognize. Not everyone on reddit is young enough to recall this either. Been 15 years since I took basic trigonometry.
It's the difference between knowing the equation and understanding it. As an engineer radians has been an inconvenient conversion I have to do, never given it any deeper thought. Also, after years of calculus, vector math, and fluid mechanics you push things like this out of your head. Writing the Navier-Stokes equation in non-cartesian coordinates will cause a surprising mental purge.
lucasvb · 2 points · Posted at 14:07:17 on January 9, 2016 · (Permalink)
This is also why arc length s = r•theta only works in radians. It's a simple ratio since the arc length of 1 radian is radius r:
s/r = theta(radians)/(1 radian)
We just leave the 1 out of it since it's mathematically superfluous. But the canceling of units is why it must be radians.
You can, of course, do a similar ratio using other units for angles, but the number of angular units on the bottom must correspond to an arc length equivalent to the radius, hence it's no different from just putting in the "radian to other units" conversion formula into the above equation.
I tutor physics (I'm an engineering student that was helped by this gif too actually!) And I use this whenever someone doesn't understand conversions between radians and degrees. So thanks!
lucasvb · 2 points · Posted at 13:57:53 on January 9, 2016 · (Permalink)
As a math tutor, thank you. I have an opportunity to sit down with kids one on one and really teach them math and gifs like these are a vital part to that. I wish they would be taught this in school but they aren't even though their textbooks and homework are already digital. Even for me as an engineering major find these helpful and its sad that I wasn't shown these when I was their age. We could all have a much better grasp of the math around us if we finally stop the whole "memorize a formula and plug in numbers" system we have now.
lucasvb · 10 points · Posted at 14:39:51 on January 9, 2016 · (Permalink)
You're welcome!
You know what really saddens me? Imagine how many people have set in their heads their entire lives that they're just "too dumb" for math, when all they needed was someone putting the effort to explain things more clearly.
For as long as I'm alive I'll try to fix this situation.
We're starting to move towards a more conceptual understanding of math in the K-12 curriculum. Common Core standards place more emphasis on conceptual understanding and a lot of the new curriculum being used now has a lot more of that (along with teaching standard algorithms). It's not perfect but it's a start.
[deleted] · 3 points · Posted at 14:14:53 on January 9, 2016 · (Permalink)
[deleted]
lucasvb · 2 points · Posted at 14:21:23 on January 9, 2016 · (Permalink)
I think so too. Our system is messed up, and we're stuck in ancient methods and traditions.
I think we need to gather around the best math teachers around, as well as a bunch of motion and graphic designers, and figure a way to tackle the subject in new ways using modern technology. We have so much more opportunities for teaching!
This is why I'm so deeply unsatisfied with the typical YouTube channel that teaches math and physics. They end up using video to reproduce traditional lectures. It's such a waste.
cos · 2 points · Posted at 13:42:51 on January 9, 2016 · (Permalink)
Your GIFs are great! Would you consider making YouTube video versions, so they can be played on more devices, and people could pause them or go slowly back and forth?
lucasvb · 5 points · Posted at 14:03:31 on January 9, 2016 · (Permalink)
But I'm currently working on another YouTube channel where I'll use technical animations and narration to explain math and physics in a more advance way, but still aimed at general audiences.
My plan is to cover most of the subjects in these GIFs, but more in-depth and building up to them.
[deleted] · 2 points · Posted at 14:06:31 on January 9, 2016 · (Permalink)
Oh, well then i'll just c&p my other comment for you:
That was some Sesame Street level visualization, right there. Whoever made that did very well.
God I wish there were math gifs back when I was in school. I would have understood, and probably enjoyed, much much more of my math and science classes. Thank you for your work on those.
I was the same as him. Your animations are dope. After I found out that you were the guy making the majority of those animations, I spent an hour looking at the rest of them. I wish you had animations for everything!
THANK YOU. I actually came across this gif about a year ago, and "it just clicked."
I'm from a family of teachers and I mentor myself, so I'm ALWAYS looking for a new analogy to explain an idea. This was freaking awesome.
Edit: Checking your edit... Yeah, when I saw this I did follow through to your Wikipedia gallery, and a lot of stuff did make a lot of sense then. Thank you, keep on rockin' in the free world.
This is so great for my kids! It's so abstract when you first start learning geometry. Thank you!
nplakun · 2 points · Posted at 15:52:34 on January 9, 2016 · (Permalink)
Where have you been all my mathematic life? This is exactly- and I mean precisely- what I needed to cement and internalize my conceptual understanding on many of these points. Thank you.
Wow, I've actually encountered a good number of these in the past. Didn't realize they were all by the same dude! Great work here, these are always the most helpful part of a wikipedia page.
I honestly think I just understood like 7 things I didn't know before. Not even related to geometry. Like how my vacuum works and why yellow and blue make green. Don't know how you did that.
Srsly tho, I'm very impressed by your gifs, they really are some of the clearest explanations of maths I've ever seen, I really like your Fourier Analysis ones.
What kind of software do you use to make them? I've been doing still graphics for a while and have wanted to get into animation but I'm not sure what would be best to start withNever mind, I found the comment where you say
if you make one showing that a cat is homeomorphic to a coffee cup, you'd become like an internet God or something
lucasvb · 2 points · Posted at 18:03:50 on January 9, 2016 · (Permalink)
Shit, it took me forever to find the parametric equation for a coffee cup. Imagine how long it's going to take me for a cat!
All through high school and well into college, Trigonometry never clicked with me. In fact, that's a big factor as to why I got frustrated with school and dropped out after my associate's.
I just want to say, that if I had been shown something like this when I was in high school, I think the effects it could have had on my future academic career are incalculable.
Seriously, if you get the opportunity, see if you can't work with schools or textbooks or some educational programs. If you can get this into classrooms, I don't think there's a limit on how many students might be helped by this.
Keep being awesome.
edit - missing if
lucasvb · 2 points · Posted at 18:22:25 on January 9, 2016 · (Permalink)
One of my long term goals is to lead an effort to completely reconstruct the entire math, physics and chemistry curriculum up to 2nd year college at least.
Preferably if all this material eventually becomes public domain so nobody else ever has an excuse to teach using shitty resources.
Are you a fan of Jim Blinns Mechanical Universe? "Remember this equation, you'll need it later..."
lucasvb · 2 points · Posted at 18:31:35 on January 9, 2016 · (Permalink)
Fuck yeah, huge fan. It's amazing.
[deleted] · 2 points · Posted at 18:29:30 on January 9, 2016 · (Permalink)
[deleted]
lucasvb · 2 points · Posted at 18:35:27 on January 9, 2016 · (Permalink)
I had plans on a proper countour integral set of animations, but I never got around to it. I felt I needed to study complex analysis a bit more formally to be up to par.
Thank you! I've seen your work before but I was on mobile so I couldn't bookmark your gallery. I'm about to be a high school math/physics teacher and am SO planning on shoehorning these in somehow. Your animations and http://betterexplained.com/ are great for non-math-heavy explanations of processes and phenomena.
I really liked this explanation of sine and cosine for students.
This is a fantastic gif! My AP Calc teacher did almost the same demonstration with colored markers on a whiteboard and it really helped everything make a lot more sense. I'm sure your gif is going to give people a lot of "a-ha" moments, and that's awesome!
I used to make some animations of my own in my time as a physics student. I mostly used Wolfram mathematica since it was easy to use with programming AND drawing, but it does have some limitations. Your animations look way more elegant!
Anyways, if you want, you can check out my animations on the bottom links and you have my full permission to copy any ideas or reanimate them if you think they're worth it, I would like to see them done in your style!
[deleted] · 2 points · Posted at 19:33:52 on January 9, 2016 · (Permalink)
You are the author of eigenvector animation?
Dude, I am soooo thankful for that animation. So brilliant and simple. I have linked it on my twitter account and said "where was this animation when I was taking Lin ALgebra 10 years ago"
Thank you again.
lucasvb · 2 points · Posted at 19:35:32 on January 9, 2016 · (Permalink)
You're welcome!
Araeven · 2 points · Posted at 19:48:30 on January 9, 2016 · (Permalink)
After multiple years of calculus rads finally make sense. Wish I had seen this in my first year of university, it would have made life easier
Why would you rename r to rad? Writing 2pi r would have made sense as well
lucasvb · 2 points · Posted at 14:11:00 on January 9, 2016 · (Permalink)
I didn't rename anything.
The circle can have any radius. That's why I called the radius r.
The "rad" in there is for specifying the unit of "radians".
Note that some people will say that radians are "unitless", but that's incorrect. Radians are dimensionless units, and so are degrees. A unit is just a standard you use for measuring something, so specifying it can be important.
Also note that I take a lot of care in color coding things. The r and the red arc are red because they are related. The angle and the "rad" are green because they are related.
But the animation isn't really a software issue. I'm a big fan of traditional animation and I'm super into motion design. I try very hard to use these principles in the stuff I do, to make the animations as effective as possible as educational content.
It's a lot of extra effort, but it really pays off, judging from the reaction of many people.
I have my engineering degree and I've only seen this afterwards. I never knew the connection. I just accepted that it's 2pi all around. I wonder how much else was just taught badly and thus didn't click back in the school time.
Hey, do you mind explaining how you made this one? Specifically the bending around its own axis part. I often try to make mathematical animations myself too but I can't wrap my head around how this is done. Also, thanks for your hard work on all the gifs!
lucasvb · 1 points · Posted at 14:58:31 on January 9, 2016 · (Permalink)
Sure.
The vertical lines are actually very large circles with centers way to the left. I figured how to scale them "linearly" from infinity, reducing their radii while moving their centers to the left.
This is done with a "t" parameter that goes from 0 to 1. At zero, the radii of all circles is zero and their centers are at the origin.
The function is mapped in a modified polar coordinate system based on the circumference of these large circles, instead of the angle from the origin. Took a few napkin sketches and GeoGebra simulations to get all of this right.
I don't think I have the source code around right now, otherwise I'd show you.
Business major so I don't need to know radians anymore, but it still clicked fam!! Good job on that gif!
[deleted] · 1 points · Posted at 15:01:09 on January 9, 2016 · (Permalink)
You're a god among men
[deleted] · 1 points · Posted at 15:01:16 on January 9, 2016 · (Permalink)
Thank you for making it slow enough to follow along.
lucasvb · 2 points · Posted at 15:04:22 on January 9, 2016 · (Permalink)*
I put A LOT of effort in the animation timing and pauses, as well as the color coding. It pays off tremendously for animations.
It really pisses me off when educational animations are too fast, have a bunch of labels the user needs to read simultaneously, or don't pause long enough for each step to sink in. It's such a waste of efforts!
[deleted] · 2 points · Posted at 15:08:16 on January 9, 2016 · (Permalink)
Leaving the big pause at the end, and colouring the labels go match the diagram... It is the best!
Question, I am assuming that the small piece of the rad is .14~. Is that correct?
lucasvb · 1 points · Posted at 15:44:58 on January 9, 2016 · (Permalink)
That's correct!
I'm going to update the animation sometime in the near future to make that more explicit. I really shouldn't have shrunk the red arc in that section, as it breaks the general narrative.
I also should highlight that it's 3 + 0.1415..., and THEN write that it is equal to pi.
So there's still a lot of room for improvements here.
I think your visualizations are fantastic. I think you would find a lot of interest. You could crosspost to r/pics or other broad interest subs. r/engineeringporn would probably enjoy them as well, but it's nice to find these kind of visualizations all in one place.
These are really great. I find it really fun to try to simplify (or rather make more intuitive) explanations of things. I wish I coul dfind some way to just do that for the rest of my life. Can I ask what you do for a living?
lucasvb · 1 points · Posted at 16:32:37 on January 9, 2016 · (Permalink)
Can I ask what you do for a living?
I'm currently a physics student, but what I do "for a living" is some occasional freelance coding and being frugal as fuck.
That's great. Any way to animate an explanation of the adiabatic lapse rates?
lucasvb · 2 points · Posted at 16:34:06 on January 9, 2016 · (Permalink)
Probably. I love getting requests, but since I'm not a genius a lot of stuff goes over my head and would require a lot of effort to simply understand it well enough to make a proper animation.
You'd own it. I think you've got a real opportunity here because it's inventive thinking. The iBook would be interactive and show the animation. You'd basically have a trademark and copyright on the material.
Check out the iBooks Author conference if you're interested.
monsto · 1 points · Posted at 16:52:37 on January 9, 2016 · (Permalink)*
I've never been a math guy, but i never knew what the hell a radian was. Even after looking it up, the explanation was just bad. It's the Simple shit like this.
I haven't looked yet, as I'm on mobile, but do you have a gig of all the myriad ways that phi appears in nature?
lucasvb · 1 points · Posted at 16:56:19 on January 9, 2016 · (Permalink)
It has an interactive Flash applet, so it won't work on mobile, but the rest of the post should be fine. Be sure to check the applet once you're on a computer.
monsto · 1 points · Posted at 18:05:36 on January 9, 2016 · (Permalink)
as a (former) environment designer in video games, using phi was essential to making spaces feel right. I'm trying to impress this asthetic upon my kids.
PRiles · 1 points · Posted at 16:55:24 on January 9, 2016 · (Permalink)
Won't lie, that it makes some sense but I was confused at to why it got cut short at half and didn't just keep going around the full circle. But it was still very informative l, thank you.
lucasvb · 1 points · Posted at 16:58:51 on January 9, 2016 · (Permalink)
It got short because we decided π should be defined as circumference/diameter, instead of circumference/radius. So now the special constant we defined represents half of the circle in radians. Stupid.
This is why the proposal of τ = 2π as a circle constant (or, as I prefer, the angle constant) makes sense.
Do you have a version with tau radians? I honestly believe this wouldn't have been such a revolutionary concept for so many commenters in this thread if 6.283 was taught in schools alongside pi. (Unlike /r/tau/ I believe they should both be taught.)
lucasvb · 1 points · Posted at 17:01:12 on January 9, 2016 · (Permalink)
You've written the best meta-discussion of tau I've ever read, and I agree with it. However, it's the section called "Dimensions" vs. "units" that really blew my mind. You've confirmed (and clarified) something I've long pondered.
For the past fifteen years I've been working on a philosophy I've been calling Triessentialism. I stumbled across the root concept in 2001, and my own "conceptual analysis" of it has shaped how I understand the world. Basically, there are three types of things: the Physical (the What), the Logical (the How), and the Emotional (the Why). They're fundamentally incommensurable (a word I learned thanks to you and Wikipedia), and they all play by their own rules. These concepts are imbedded in all philosophies across the millennia, usually hidden or badly grouped, but they're always there.
It's also a fractal ontology: each of the main categories has three similarly differentiated subcategories. I won't bore you with those details here, but you've just given me the key to my conceptual categorization of the physical: Mass ~= Physical (What), Time ~= Emotional (Why), Length ~= Logical (how). (Length must be measured against a standard rod, and is fundamentally rational. If this sounds like a cobbled-together explanation, I don't have space here to explain why it's not.) I'd previously matched up Mass = What and Time = Why, but not Length = How.
So, thank you for more than just the awesome animations!
yanroy · 1 points · Posted at 17:07:51 on January 9, 2016 · (Permalink)
I'm an electrical engineer. I've been intimately familiar with radians for years. I intellectually knew everything in that gif, and yet I never would have been able to explain it to someone so elegantly. I can't put my finger on what I just learned, but it was important.
CCNezin · 1 points · Posted at 17:59:45 on January 9, 2016 · (Permalink)
Thanks :)
[deleted] · 1 points · Posted at 17:21:18 on January 9, 2016 · (Permalink)
That really was an excellent visualization. Thank you.
Namhaid · 1 points · Posted at 17:22:05 on January 9, 2016 · (Permalink)
Check my Wikipedia gallery
I just did this, and realized that you're the author of so many gifs that have helped me. My hs math teacher hated me and kept me from learning, and so I only recently got back into the subject when I began exploring coding, and I can't tell you how awesome many of these visualizations were for my progress. Keep it up.
Visualizations such as yours would go a long way in school for a lot of people. Too many students don't understand the basic principles then give up on any of the follow up content. These gifs and images would go a long way.
The other website adds another layer to the joke, though, if you scroll past the end.
raznog · 5 points · Posted at 13:07:37 on January 9, 2016 · (Permalink)
Oh come on it was a fun story.
Fudge89 · 1 points · Posted at 20:02:56 on January 9, 2016 · (Permalink)
I love it. I wasn't even mad after reading it. I just have to be sure to pass it on as much as I can to compensate for how much I cried later on that night. I divorced my wife and moved back in with my parents after I read it. I'm doing fine.
Keep up the good fight. I did well with geometry but the "Greek" math never worked well for me, I think mostly because I couldn't understand what exactly it was accomplishing. Just plugging stuff into formulas isn't learning. Anyway, things like this would have made a huge difference for me in the classroom. Don't give up on kids like me! We are smart I swear!
Gif,no. A real machine brought that to my reality.
[deleted] · 48 points · Posted at 15:23:53 on January 9, 2016 · (Permalink)
...how do you not understand that in your 3rd year of engineering school?
Zjurc · 7 points · Posted at 20:47:18 on January 9, 2016 · (Permalink)
I'm surprised he made it this far without hearing anyone at least mention this relation - then again, learning and understanding are two completely different things
He's flunking out soon, is going to a very low ranked engineering school, or is lying. He basically just said, "Oh, I just realized that pi is the ratio of the circumference to the diameter". I'm sorry but there's just no way.
[deleted] · 1 points · Posted at 15:40:34 on January 10, 2016 · (Permalink)
The vast majority of science/engineering/CS grads memorize and plug&chug equations for tests. Then they do a core dump to be fresh for the next semester. Actually understanding is tough. I knew straight A students who didn't understand a damn thing.
[deleted] · 1 points · Posted at 04:12:54 on January 10, 2016 · (Permalink)
I am a (former) straight A student with a masters in engineering. Yeah I can memorize the process behind Cauchy's Integral Theorems and know how to use them to solve complex differential equations... but understanding WHY they work is still kind of a mystery.
But like.. radians? This is like really really basic stuff. I understood this in like 10th grade
42 year old EE here. I use the math basically never. But I use the concepts every fucking day.
I'm fairly successful, and try to surround myself by other successful people. I've had lots of conversations where we say " I wish I had paid more attention in my ______ class". Not once have I heard an associate say they felt they over-learned a subject.
There is no way you will use everything you learn in school. But you won't know for another 10 years which topics will turn out to be useful. So study your ass off, and do the best you can in every class.
You are setting your career for the next 40 years. Set yourself up for success!
The thing is that "I wish I spent more time doing x" does mean that they wish they spent less time doing something else.
Sometimes you might find that the rocketry club (for example) is more interesting than your degree and you are doing your degree so you can keep doing that. In university sometimes the degree isn't the important bit.
I would argue that usually the degree isn't the important bit. It's everything surrounding the university experience and how that shapes you as a person that is the most defining portion.
That's great advice, and also learn as much as you can outside of your field. I roomed with a bunch of engineers in college, and work with them all the time in my career. It takes them a few years beyond college to realize they are not the smartest people in the world, and they they don't know everything. I'm getting a kick out of some of these responses.
My friend in civil is laughing so hard at his classes. The physics is almost not existing and if you can learn good from books you don't have to spend a lot of time learning.
Hmm shame, but yeah if you say it's necessery haha. It's still quite easy for me but I really do need to my homework because I now do it just the week before the test.
yeah I know that I need to get good study habits and it's not like I don't do anything but I'm just saying that I'm having it quite easy at the moment, yes I have to do something for it but it's not overtaking my life or something.
[deleted] · 1 points · Posted at 12:57:56 on January 9, 2016 · (Permalink)
I'm having it quite easy at the moment
Don't slack: Use this to your advantage. Study that shit and nail it. Get them A's.
in my 3rd year doing Engineering. If you can learn eigenvalues + eigenvectores inside out, such that you'll never forget it. They pop up all over the place :). Some bits of the math you won't use (the more abstract stuff), but lots of it you will. Unfortunately it's hard to know which bits are and aren't relevent (some bits are more relevent to those who will study pure maths, and some more relevent to engineering/physics).
I recently used calculus at my job, 24 years after I finished my undergrad EE degree. I'm a SW engineer now and was working on an optimization for an extremely high precision positioning system. But it was only basic differentiation. I have yet to use integration, but I have some colleagues whose job it is to do high-level math stuff like modeling random processes.
So ... I concur with laseralex. You never know what you'll need at some point down the line. If I had slacked during my calc classes I most likely would not have figured out the issue I mentioned above.
Do you mean solidworks with sw? If so can you really trust the calculations solidworks makes? To a noob engineer like me it seems impossible that it can calculate a simulation the way it will behave in the real world.
Nope no solidworks going on for me. A bunch of much-smarter-than-me types came up with a characteristic function that described the position error based on a few other parameters. I had to figure out how to use this in an application.
I too am amazed with some of the SW tools available. The ones that I see used "in the shop" do a pretty good job of approximating sensor signal traces and such, but of course the real-world signals aren't quite as "neat".
I don't mean to be rude but how on earth did you get 3 years into any relevant engineering field before being able use radians and understand them. We had to learn them and be tested on full understanding a year before even applying to university. Crazy
I don't think s/he meant s/he didn't know how to use radians in mathematics. The gif visualizes the "length" of one radian. I didn't actually make the connection until just now either. I am also in my third year of my engineering education, and I've been plenty successful in my use of radians in my math courses regardless.
EDIT: For the people who are telling me I have no idea what I'm doing in math, it's fairly clear that this entire string of comments is relating to the ORIGIN of the radian not how they're actually used. But please continue to tell me how I don't actually understand math and am somehow just breezing through my university courses without actually knowing my shit.
EDIT 2: since I'm still getting comments telling me about when they learned about radians (hint: I don't care) what I meant when I said it clicked for me was that I hadn't thought about the arc length of a radian since I learned it and since must have forgotten the connection. That's all... now please stop telling me about how good you are at geometry.
If you didn't know or understand the definition of one radian then you really didn't know what radians were, you just learned by rote how to use them in certain contexts.
It's like in pre-calc physics, where you're presented a whole bunch of projectile equations that you essentially have to memorize because you don't know calculus. A waste of time IMO. What's the point in teaching memorization? Just wait til you have the proper framework to understand more thoroughly and it becomes much easier.
Seriously. Calc should be a prerequisite for any physics course.
Rebmes · 1 points · Posted at 17:43:05 on January 9, 2016 · (Permalink)
I would say that spending a year using those formulae without calc was absolutely beneficial. I wasn't ready to understand the calculus but I got all of the conceptual stuff down.
I'm not sure how you can really conceptually understand force =ma, momentum, etc. without understanding the mathematical relationships between distance, velocity and acceleration and force and momentum. Sure, you can give something a force it accelerates, but to start calculating motions means you are either blinding using equations from a book or you know calculus. There's a reason the man behind F=ma was also one of a couple behind the formation of calculus.
Rebmes · 2 points · Posted at 20:05:58 on January 9, 2016 · (Permalink)
I'm not talking about necessarily understanding conceptually the equations, I mean understanding what acceleration or velocity is, how basic vectoral operations work, etc. We tended to not focus on the math as much as reasoning and understanding very basic kinematics and electromagnetism. Of course knowing the calculus behind everything would make it easier and a bit more clear, I'm not denying that.
Calculus really isn't that hard if taught well. I remember when I first learned it so many of my questions about the world were answered and I wondered why they didn't teach it to everyone (at least on a rudimentary level).
Rebmes · 2 points · Posted at 00:35:58 on January 10, 2016 · (Permalink)
That's true but there really isn't enough time anymore (at least for AP Physics I) to teach the calculus and the physics when most of the students are only in precalculus. What you're advocating certainly makes more sense if it's all or mostly seniors in the class already have a good grip on precalculus and are learning calculus simultaneously but that's not the case anymore in AP Physics I. In AP Physics C that is the case so the College Board feels more comfortable introducing calculus. Is this the right way to go? I really don't know, but I see why they did it. I was the first year to take the new Physics I Algebra-Based course and it seemed that we were less crunched for time and able to go into greater depth when talking about a lot of things even if we were unable to do that math.
Well, that still seems better than my high school experience. It was a while ago, but there were only a few AP courses and none were in the sciences. I'm actually far enough removed from high school that I probably have no idea what's going on anymore, haha.
Which unfortunately is how you can get through calc 1-3, linear algebra and diff. equations. I mean, they're supposed to be the building blocks for higher math, but only if you actually understand the material. Getting through without much understanding is entirely possible, unless your professor is very, very proof oriented.
I didn't say I didn't understand the entire thing. You're making assumptions about what part I meant I said "clicked" when I watched it.
But I don't need to justify myself to you. I'm doing quite well at a prominent American university and have no desire to continue justifying my math skills to you.
But your original comment is explicit about the fact that you didn't understand how one radian is defined and how it relates to arc length. And that you simply knew how to use them in practice. All my comment says is stuff that you later edited into your own comment. Stop being a manbaby, it's really tedious.
That is really surprising. Because I learnt about radians in second year of high school and this gif is basically the physical interpretation of the mathematical definition. You divide the circle into "2π parts" each of which subtends an equal angle (1 rad) at the centre.
I don't think you understand what he (and I) are saying. We know that a circle is 2pi radians and we can use them in math, it's more about the origin of the radian than anything else.
And I'm saying that I (and most of my class) understood the "origin" before being able to use radians as well as degrees. A lot of things fit beautifully together. The circumference is 2πr. π is the ratio of of the circumference to the diameter (same as the previous, I know). Radians are called RADIans because its the angle subtended by a portion of circumference equal to the RADIus. I'm saying that all these things (for me, at least) clicked the moment I was introduced to radians.
Well congratulations, you're better at radian history than me, is that what you needed to hear? I probably was told that at some point and just let it slip away after it became irrelevant; because let's face it, as engineering students it's much more important to know how to use math than to understand its definitions. The theory is for the mathematicians to sort out.
That's the problem with engineering school. It throws a ton of concepts at you without explaining any of them and then rushes you through all of them so everything just becomes words on a page. I used to hold math tutoring for lower class men and I'd draw this stuff out. It only clicked for me then.
That's a really broad generalization. When I took engineering in college the curriculum went deeply into the theory and origins of concepts. Professors regularly took the time to show derivations in lectures (or at least tell you where to find them).
Fair enough. I can only speak for my time at a highly rated engineering school, but our professors were so concerned with their research, the classes were an afterthought for them and they regularly were not available during office hours. They would just throw concept after concept out in class with no explanation of where it came from. We used to joke electricity was just a magic thing in a box from a wizard because we barely understood the concepts.
[deleted] · 1 points · Posted at 19:14:02 on January 9, 2016 · (Permalink)
Congrats, I'm doing quite well without knowing the origin of radians thanks ;)
[deleted] · 1 points · Posted at 05:28:19 on January 10, 2016 · (Permalink)
I'm just curious - how was the concept of a radian introduced to you then? Did they just say "here's a new unit we're using now" and leave it at that, no questions asked? Or pi? Surely someone at some point explained that it wasn't just a random assortment of numbers?
I'm just not sure how the radian gets brought up without an explanation of what it is in relation to a circle.
I have no idea, it's been nearly a decade since I first heard the word radian. I was probably told what they come from and let it slip away because it's irrelevant to your ability to use them in mathematics.
Well then you must both be taught pretty poorly if you are only told how to use them and not what they are.
That's no way to learn maths
Jora_ · 3 points · Posted at 13:00:27 on January 9, 2016 · (Permalink)
That's no way to learn maths
Which is probably fine because s/he is studying engineering.
I would argue that an engineers ability to assess stress, fatigue, shear etc. of materials does not depend on having a fundamental understanding of the chemical interactions of that material at an atomic scale. Sure it might help, but it is not essential and certainly not indicative of poor teaching.
Similarly the theory behind radians is not an essential prerequisite to using them as a tool in engineering.
Same with biology, I use math to model population dynamics, I use the logit tranformation to keep changes to a survival rate between 0 and 1 as a function of shocks, I have no idea how exactly it does that but hey it works, and the math guys say it's legit.
As an engineer I beg to differ. An engineer might be able to get by blindly using sets of equations as tools, but that's just asking for problems. IMO a firm understanding of how and why the math works is critical to understanding how to apply it.
Jora_ · 1 points · Posted at 02:02:53 on January 10, 2016 · (Permalink)
I'm an engineer myself. Day-to-day, I do not need to know the fundamental principle behind every mathematical tool I use, in the same way I don't need to know the source code for the programs I use.
Engineering is about practical application of theory, not necessarily theory itself.
I suppose it depends on the type of engineering. I work in a field where fundamental understanding is often critical. I also frequently do need to the know the source code for the programs I use, because I often have to write them myself.
I view it as a requirement in my area, and honestly can't think of any others where it wouldn't be at least a distinct advantage.
Which is probably fine because s/he is studying engineering.
Then it isn't relevant was only put in to make them sound smarter. If you don't need this stuff in your life then why are you mentioning it? It's like saying "Well I graduated from law school last year but only now do I understand the sine rule"
It just reads as "I know this is going to sound stupid but honestly I'm a really smart person; look, here's proof!"
In an ideal world you're right. No one explained what radians were to me until it randomly came up in my calc 2 class a few semesters ago. No one every bothered. I memorized the unit circle but no one taught me that 1 radian was just the arc length of the radius length.
Some people understand some concepts of math better than others. I agree though, and the US is actively trying to change this.
[deleted] · -1 points · Posted at 12:59:49 on January 9, 2016 · (Permalink)
I have to agree... this is a basic concept I learned in middle school. It really is something that is easy to visualize and could give people a better insight in how the principle works, so I don't understand why some education systems or schools don't employ such tricks.
I'm glad you agree, maths should be learnt by understanding how things happen. That's why maths lessons are built up over years and not taught at complex levels at a very early age. Because it gives you knowledge of how the stuff you learn one year will influence you the next.
You know nothing about what I know and don't know, unless of course you are gifted with telepathy through the internet as well as your glorious 'maths' education.
It's the difference between understanding and comprehension. He probably understands radians and how they work fairly well. But perhaps the visualization helped it click in his brain, and now he comprehends the concept.
English is not my primary language, so I suppose I may be wrong. What I've been taught is that comprehension, due to its Latin root, has the meaning of grasping/encompassing. Thus, to comprehend is to fully internalize a concept, compared to the perhaps shallower knowledge implied by understanding.
It's not even remotely necessary to understand the origin of the raidan to use them in calculations. More to the point, understanding this concept doesn't get you anything.
You probably learned how to use the fundamental theorem of algebra a long time ago.... can you prove it?
Gripey · 1 points · Posted at 14:51:18 on January 9, 2016 · (Permalink)
I reluctantly agree, but I would add that I only understood pi was "just" the ratio of the diameter needed to go around the perimeter of any circle in my fifities. Lights went on all over my maths history. It gives you the confidence to work things out instead of just remembering. I used to think pi was a magic number...
You probably learned how to use the fundamental theorem of algebra a long time ago.... can you prove it?
This isn't anything even close to a proof, it is just how something works. It is a poor way to teach maths what happens instead of how. Understanding how is the key to understanding what, and without knowing how it's very hard to accurately and efficiently use the what.
You could spend all your time exploring the origins of every single concept you need to use in math. And then you'd get literally nothing done.
Well technically you'd be a mathematician and might further the knowledge of others, but that's not the point.
You are trying to claim this obfuscates some deeper insight and that is just false.
No it's a bad way of teaching and a bad way of learning. It sets bad standards
MyButtt · 0 points · Posted at 12:47:42 on January 9, 2016 · (Permalink)
It's not like everybody wants to or is going to be a great success in math, science or engineering like you.
[deleted] · -1 points · Posted at 13:00:56 on January 9, 2016 · (Permalink)
He never suggested anything like that.
It is poor teaching, especially since it's such an easy concept. I learned this in middle school and understand it to this day and I don't even study anything remotely similar to math.
MyButtt · 0 points · Posted at 13:13:20 on January 9, 2016 · (Permalink)
It is poor teaching, especially since it's such an easy concept.
And what I'm saying is that he would know since he's so very smart. Look, different people learn things differently and for some even the most succinct explanations and diagrams might not get the concept to click in the way a 30 second gif will.
[deleted] · 0 points · Posted at 13:43:37 on January 9, 2016 · (Permalink)
for some even the most succinct explanations and diagrams might not get the concept to click in the way a 30 second gif will.
Perhaps. Does that mean we shouldn't try to include frame-by-frame like diagrams in textbooks? Because with a few frames, the concept will become clear even without animation.
MyButtt · 0 points · Posted at 13:47:49 on January 9, 2016 · (Permalink)
Perhaps. Does that mean we shouldn't try to include frame-by-frame like diagrams in textbooks?
Nobody is suggesting that or anything close to that.
Because with a few frames, the concept will become clear even without animation.
For most people. For some it will take an animation and others maybe something else.
You can but it's not a good way of learning, especially in maths. You can fix a car without doing any mechanical qualifications and you can fly a plane without a license, but good luck trying to get a job in a relevant field without being able to show you have the understanding
I only understood these because rotating images in the framework i use is done in radians, not highschool, not university, nothing else made sense besides practical experimentation i guess.
[deleted] · 2 points · Posted at 21:22:26 on January 9, 2016 · (Permalink)
Also in 3rd year of engineering school. Someone could have told me radian is called a radian because it's the length is the circle's radius. Is it that so hard? When I first had pre-calc (covers trig at my school) I was happy the professor showed a gif that described pi.
[deleted] · 1 points · Posted at 14:38:01 on January 9, 2016 · (Permalink)
Well, the circumference of a circle is pi times the diameter (D), or pi times 2r since 2r = D.
We learned that, but that's not where radians come from. Arc length only showed up formally in freshman geometry, and the word radian was not uttered until Junior year pre calc.
You would be surprised how common that is. I remember it took me quite sometime to realize some simple relations trigonometric functions . . . to embarrassed to say what they are though!
Let me guess, your teachers did a lot of "just accept it, that is how it is." I had a really good calc professor in college (Calc 1&2) who actually didn't hand waive anything. I always respected that he would show us as much as out level of math taken would allow.
This isn't something that clicked in high school math? I thought it was pretty instrumental to even pass the most basic questions of it?
[deleted] · 1 points · Posted at 17:28:11 on January 9, 2016 · (Permalink)
What engineering are you going for?
bitwaba · 1 points · Posted at 17:29:09 on January 9, 2016 · (Permalink)
I was a math major in college. It wasn't until I was about 26 that I realized a radian is the measure of the Arc Length drawn by that "radian" on a unit circle.
With a unit circle, your radius is 1. The circumference of that circle is 2 * pi * r = 2pi. Just to keep it simple, if you were to measure 90 degrees angle, the length of the arc on the unit circle would be 1/4th of that 2pi. So, (1/2)pi. Guess what the 90 degrees is in radians? Yep! (1/2)pi. Just for reference, the formula we used when all put together is (frational portion of circle you wish to travel around) * 2 * pi * r.
How is it useful? Say you're about to drive on a roundabout with radius 12 meters, and your exit is 7/16ths of the way around the circle. How what would your odometer measure your distance as when you get to the end of the roundabout? (7/12) * 2 * pi * 18 meters = 21*pi meters, or ~0.065 kilometers
When that clicked in my head, I felt like the universe had opened up to me... or at least 10th grade trigonometry.
[deleted] · 1 points · Posted at 17:29:41 on January 9, 2016 · (Permalink)
How was everyone not taught this the first time radians were mentioned in 10th grade? It's such a core concept, I couldn't have gotten through HS math without it.
Not an engineer but my son is in a Montessori school. When they taught the Pythagorean theorem they actually laid out a large right triangle on the floor and had the kid stack cubes along each side to form a square so they could physically see A2+B2 =C2. Mind blown, I just had to memorize the formula I never visualized it or understood it like that. Why isn't all math explained that way?!
Rebmes · 1 points · Posted at 17:41:03 on January 9, 2016 · (Permalink)
Halfway through AP Calc. Just clicked for me too.
Arusht · 1 points · Posted at 17:49:20 on January 9, 2016 · (Permalink)
Don't worry, I first saw this gif half way through engineering school, as well. How is it that we can make it so far in math, without ever being shown this?
I dropped out of highschool then got my shit together and dropped out of Oregon state I have literally no clue what's going on or what this represents. I come to explain like I'm five so that I might learn something new and even though I can't appreciate this .gif I appreciate that you appreciate this .gif.
Your mind is really going to be blown when you start work with phases (of electricity and electromagnetism) and realize that Pi doesn't belong to circles at all, but to the trig functions.
Halfway through my 3rd year of engineering school, it just clicked.
More evidence that engineers are retarded.
[deleted] · 1 points · Posted at 09:37:57 on February 1, 2016 · (Permalink)
?
[deleted] · 1 points · Posted at 15:10:06 on January 9, 2016 · (Permalink)*
[deleted]
dunk_hs · -1 points · Posted at 15:35:02 on January 9, 2016 · (Permalink)
If you were an employer/customer would you hire an engineer who doesn't understand basic engineering math?
The fact that this guy got through 3 years is either a miracle or a failure on behalf of his teacher(s).
[deleted] · 1 points · Posted at 15:57:27 on January 9, 2016 · (Permalink)
[deleted]
dunk_hs · 2 points · Posted at 16:14:28 on January 9, 2016 · (Permalink)
I would never ask them to show me precisely what a radian is.
Yeah, that's exactly the problem. People get degrees that prove they know stuff they actually don't. In one year this person will be out in the wild designing bridges/electrical/mechanical systems or who knows what other things without knowing what a radian or sin is. It's dangerous to say the least.
Ebolinp · 0 points · Posted at 13:35:31 on January 9, 2016 · (Permalink)
I graduated from Engineering school 10 years ago and I just got it...
dunk_hs · 0 points · Posted at 15:32:24 on January 9, 2016 · (Permalink)
Am I just weird then? Why is it so damn difficult for people to understand this shit? It's not difficult at all. It's either people are way dumber than I thought before...or maybe I'm actually learning a fuckton in my degree program without realizing it (math major)
eeeeeep · 0 points · Posted at 13:29:35 on January 9, 2016 · (Permalink)
Don't know how to ask this question, but what are we adding for pi? The number of pi? So its 3 rads + 3.14 to make half a circumference? What unit is pi in, cm? So sorry I suck at maths.
How to you get in your 3rd year of engineering without needing that info? I'm in my 2nd year and I have used that so many times.
BBrown7 · 0 points · Posted at 15:12:10 on January 9, 2016 · (Permalink)
Can confirm. Saw this in highschool and basically shit my pants with the sudden flow of calculus I now understand. Am now almost done with my second year of engineering.
Now that's what I call getting off on a tangent...
[deleted] · 1 points · Posted at 13:02:10 on January 9, 2016 · (Permalink)
LOOK AT THEM CURVES
[deleted] · 1 points · Posted at 02:32:10 on January 10, 2016 · (Permalink)
Yo dawg I heard you like derivin' so I put a function in your function so you can derive while you derive.
[deleted] · 41 points · Posted at 11:56:50 on January 9, 2016 · (Permalink)
Interestingly, this is a wonderful demonstration of how epicycles work, and the reason why the geocentrists were able to keep their model by adding more and more epicycles (orbits within orbits within orbits) - they were essentially performing Fourier decomposition of the orbit by hand. It was inelegant and ultimately useless because Kepler showed you can think of it in much simpler terms as an ellipse - but it was mathematically correct.
[deleted] · 14 points · Posted at 12:15:00 on January 9, 2016 · (Permalink)
Yep. Epicycles are virtually complex Fourier analysis. Any smooth curve on the complex plane can be approximated with arbitrary precision.
Just goes to show how overkill and desperate geocentrism is.
Initially heliocentrism still needed epicycles to account for the fact that the orbits aren't perfect circles. Its main advantage was that it needed less of them.
mwobey · 3 points · Posted at 12:53:42 on January 9, 2016 · (Permalink)
I don't know, I think they make some pretty good points. I think we should teach both sides in science class, and let children come to their own conclusion.
Drasern · 8 points · Posted at 13:20:08 on January 9, 2016 · (Permalink)
And then mock them when they reach the wrong one.
DXPower · 3 points · Posted at 14:13:28 on January 9, 2016 · (Permalink)
Then we might as well teach spontaneous generation, steady state theory, intelligent design (already proved to be not science). When you have mountains of evidence and suddenly you have a few people with no formal education that say it's wrong, they don't have any credibility in any academia field. Why should we teach their babbles that often form unnecessarily ad-hoc explanations and make no useful predictions. The reason why we teach only one side in science classes is because the other side can't make any predictions based on a mathematical model, and thus is pseudoscience because it cannot be tested.
There is a great (albeit long) series on YouTube called Testing Geocentrism if you want to learn more about its problems (and it's fairly entertaining as well)
mwobey · 5 points · Posted at 15:51:10 on January 9, 2016 · (Permalink)
I remember when it first clicked in my mind, I had to just sit there for a couple of minutes whilst everything I learnt about the frequency domain clicked into place.
[deleted] · -5 points · Posted at 16:17:43 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 3 points · Posted at 16:53:34 on January 9, 2016 · (Permalink)
What a useless comment. And how fucking rude.
There are many ways of considering, visualising and using mathematical constructs, and contexts within which to apply them. To see them in a different way is just that. It doesn't make the work I've done with them so far useless or invalid. To try to belittle someone for not seeing them the way you perhaps saw them is petty and belies deep insecurity. Seriously, what value did you add to this? What is the point of anything you said? Nothing.
Take your rude, condescending and needless insult and fuck off back to your sperglord mindpalace.
I use a custom-drawing library for 2D/2.5D and POV-Ray for the fancy 3D stuff. The drawing library was cumulatively developed over the years on top of GD in PHP, due to historical reasons.
Most existing software are too specific and/or too cumbersome to do the kind of stuff I want to do. I always need some artistic freedom they didn't offer, or which is pretty hard to achieve. So I had to use a drawing library. Check the FAQ for more on this.
Now, I've been working on a similar library using OpenGL and Python, but I'm having problems getting the hang of shaders. Looks like I'll have to roll out my own line and polygon drawing stuff too, which I'm fine with since it'll be a good way to learn OpenGL.
I'm doing this because I've been working on a YouTube channel where I'll use more technical animations and narration to explain math and physics concepts to a general audience.
Most YouTube channels are superficial about math and physics ("an electron is a particle... AND a wave! wow!", and then the video ends) or too technical (some dude boringly writing on a paper/chalkboard, pretty much a formal lecture, an ancient format that isn't trying anything new).
I think there's room for improvement. But for the videos I'd need a larger amount of frames at 1080p and my current setup isn't going to work.
H2C2O4 · 5 points · Posted at 22:10:12 on January 9, 2016 · (Permalink)
I recognize a large portion of your illustrations from reading various Wikipedia-articles over the years. Only yesterday I saw your scalar field png! It's amazing how much a good illustration can aid the understanding of a concept, and it's so easy to forget that there is a person behind every line of text and every picture. I'm almost as star struck right now as when the guy who made solitaire for Windows showed up on reddit not long ago.
DXPower · 3 points · Posted at 14:49:05 on January 9, 2016 · (Permalink)
You should look at King Crocoduck's Quantum Theory Made Easy series, he goes over the history and math of duality without boring you and making it easy to understand, great videos if you want some ideas on how to structure it
lucasvb · 3 points · Posted at 14:53:54 on January 9, 2016 · (Permalink)
Cool, I'll take a look. Thanks for the suggestion!
optigon · 2 points · Posted at 17:08:06 on January 9, 2016 · (Permalink)
Curious, but have you looked at Processing as a language to help you with your animations? It's largely designed for visual representation.
lucasvb · 3 points · Posted at 17:21:42 on January 9, 2016 · (Permalink)
Yes, but the real time paradigm is not acceptable for me. It's also very difficult to deal with certain high-level features I need to add.
Processing is great for non-realtime usage too - I've seen examples of people generating images over time using genetic algorithms for example, or making movies/gifs by rendering out a series of jpgs etc. For example, this Hypercube gif is probably somewhat along the lines of your explanation circle gif (though obviously I've no idea what you've got planned for the future!). The author has a lot of neat geometric gifs: https://twitter.com/bigblueboo
I'd also recommend checking out OpenFrameworks - there's a huge amount of extensions/plugins available for things like editor interfaces, UI, post-processing effects etc. Processing has those too, but for some reason I find myself more productive in OF. Either way, good luck with the project! I'm definitely looking forward to the Youtube channel :)
nfsz · 3 points · Posted at 15:17:53 on January 9, 2016 · (Permalink)*
You could start an indiegogo campaign to crowdfund a better computer setup. Ill help and i'm sure many others will be willing to help
lucasvb · 10 points · Posted at 15:27:59 on January 9, 2016 · (Permalink)
Thank you for the suggestion. But it's not the computer setup. It's really a matter of expanding the range of stuff I can do and how fast I can make animations. It's a software thing.
With my new Python+OpenGL engine I'll even have real time interactivity that will help me choose angles and adjust parameters before I make the final, high quality renders. Right now, I have to adjust and re-render all the frames, which takes a long time sometimes. A new engine will speed up things immensely.
I also don't want to disappoint anyone at this moment, so I'm taking things in my own pace. I know there's a lot of interest for this sort of material out there, and I'm excited to be able to provide it, but I wouldn't want to leave people who made a monetary investment waiting for too long. I have a lot of other personal stuff going on in my life that could get in the way.
Once my YouTube channel is going, I'll set up a per-video Patreon account so that I can keep things fair, and so people can show their support.
nfsz · 3 points · Posted at 15:39:27 on January 9, 2016 · (Permalink)
I completely understand. And as an aspiring programmer, I love how you don't settle with the limitations of the design tools already out there and craft your own solutions!
lucasvb · 5 points · Posted at 15:43:16 on January 9, 2016 · (Permalink)
Hah, I'm just a stubborn bastard. But I wouldn't have done if I wasn't into developing low level stuff. It's fun to work with the basics. Big applications are not for me.
EliteTK · 1 points · Posted at 19:33:15 on January 9, 2016 · (Permalink)*
Will this library be released under a permissive license as open source?
If you put your code on github I would be willing to help with the shaders.
Simply do as most other projects do, include a TODO for each directory explaining what needs to be done or create a list of issues for people to post PRs against.
Edit: Now I know where all those wikipedia GIFs come from.
lucasvb · 1 points · Posted at 19:35:14 on January 9, 2016 · (Permalink)
Yeah, I hope to release the Python+OpenGL library at some point. But I'm super inexperienced with OpenGL so this is probably going to be a disaster. I don't think I'm a particularly good developer.
EliteTK · 2 points · Posted at 19:57:56 on January 9, 2016 · (Permalink)
Even more reason to release it, you can learn a lot more from people criticising your work on a public platform than you will from trying to discover your own mistakes and solve them.
The point is, if your tool in any way actually solves a problem (it solved a problem for you) even if it's not particularly well written, it will attract developers who will first help put it in shape and then continue to make it better.
Consider myself subscribed to your channel. Hope to see your content in there soon :)
blbd · 1 points · Posted at 19:10:17 on January 9, 2016 · (Permalink)
You seem like the type of guy they could really use on a temporary posting to the CTO's office in the White House. I an hoping to do one someday if I can get some money from options at a startup at some point in my career.
Even though he eventually discarded Processing for his own usage, if you wanted to learn how to do this kind of stuff you could do far worse than learning how to program in Processing.
Also see /r/loadingicon and other subreddits where this kind of animation is sometimes posted.
lucasvb · 1 points · Posted at 19:31:29 on January 9, 2016 · (Permalink)
Not sure what "this kind of thing" is specifically.
Khan Academy have a whole slew of videos focused on teaching in a straightforward manner. Geometry & trigonometry are covered, but they cover a whole lot ranging from basic arithmetic to calculus.
As for the rest, things are a little bit trickier. For one, the animations are created using a custom library that’s ever changing, so compatibility is often broken with time. While I am trying to publish the library sometime in the future, I’m not terribly enthusiastic about it because I’m probably the only person who would use such a thing for PHP.
Do you keep your code under version control (like Git)? If not, you should.
In any case, you could just dump the code as-is to Github or something, even if nobody would use it.
And if you have both the code and the images under version control, that's already useful (it doesn't matter if the code is constantly changing if you can match each image to the source used to render part of it)
deshe · 1 points · Posted at 21:30:56 on January 9, 2016 · (Permalink)
Hi, I am a math Ph.D student and a TA, and I often get ideas for animations which I think could be pedagogical and fun. Are you open to suggestions?
lucasvb · 1 points · Posted at 21:47:17 on January 9, 2016 · (Permalink)
lucasvb · 3 points · Posted at 21:47:33 on January 9, 2016 · (Permalink)
I major in physics.
Vacster · 1 points · Posted at 00:38:14 on January 10, 2016 · (Permalink)
Oh man, OpenGL shaders are hell, the first time I dived into them I spent like 8 hours trying to dynamically change the color, I feel you man. Good luck with your project!
[deleted] · 1 points · Posted at 00:40:29 on January 10, 2016 · (Permalink)
POVRay! Holy hell that brings back memories of ~1996, starting a render on my 386 in the morning and going to school, hoping that it might be done before bedtime that night...
[deleted] · 1 points · Posted at 03:23:10 on January 10, 2016 · (Permalink)
You do sexy animations. Could you please do animations of common sorting algorithms as well? :) I mean, there are of course animations, they just aren't satisfying like eg. your radians one.
lucasvb · 12 points · Posted at 13:50:12 on January 9, 2016 · (Permalink)
Yes. I've been thinking about alternative visualizations of several algorithms in computer science and computer graphics. Keep an eye out.
Godd2 · 3 points · Posted at 15:01:11 on January 9, 2016 · (Permalink)
Mike Bostock (creator of d3.js) has a whole page of amazing algorithm visualizations. If you haven't seen them, they might be good reference/inspiration. (My favorite is the maze turning into a binary tree on the bottom)
lucasvb · 1 points · Posted at 15:04:48 on January 9, 2016 · (Permalink)
I've seen them all, it's a great source of inspiration. I intend to use d3.js for some interactive stuff to accompany my YouTube channel.
Holy crap, you basically made most of the educational gifs I love !
Thank you so much!
lucasvb · 7 points · Posted at 13:48:16 on January 9, 2016 · (Permalink)
Thanks for the appreciation! And you're welcome.
[deleted] · 5 points · Posted at 12:38:40 on January 9, 2016 · (Permalink)
Your animations make me believe I could almost not suck at math.
lucasvb · 8 points · Posted at 13:52:13 on January 9, 2016 · (Permalink)*
I'm glad I can give you that impression. I do believe animations and interactive illustrations, paired with a proper and new teaching strategy, can really make a huge difference in math and physics education.
Not sure if my maths is on the right track here but the "Converting from Cartesian to Polar coordinates" animation, would that be how Radiation plots are calculated?
My thinking is that in the instance of a radio antenna sending out RF energy, the frequency and the power and modulation etc would be relevant to the pattern that it would propagate within?
This way sin and cos are related to the exponential function without any ugly conversion factors in the arguments. If our angle x is measured in radians, then cos(x) = (eix + e-ix )/2.
If x is measured in degrees, it becomes cos(x) = (eixpi/180 + e-ixpi/180 )/2
Where you're more likely to meet the distinction explicitly is in calculus, where if x is measured in radians then d/dx sin(x) = cos(x) and d/dx cos(x) = -sin(x), but if x is measured in degrees you have to include a conversion factor.
Not in gif format, but I quite like this image. Definitely not ELI5 though.
Rangsk · 35 points · Posted at 11:16:57 on January 9, 2016 · (Permalink)
Radians are the only measurement of angle that is unitless. Radians are defined as the ratio of the arclength (s) and the radius (r), which is s/r. Since s and r are the same unit, it doesn't matter which unit you use for the length, as it cancels out.
Any other way of expressing angles is going to require using a unit, such as degrees.
Why is this beneficial? Well, if you have to use a unit for an angle, then random annoying constants start appearing due to the need to do unit conversions. Here's one example:
In radians:
d/dx sin(x) = cos(x)
In degrees:
d/dx sin(x) = (π/180)cos(x)
If you were to use degrees, you'd have to keep sprinkling this (π/180) constant everywhere, which is annoying and unnecessarily complicated.
Kayyam · 53 points · Posted at 12:55:59 on January 9, 2016 · (Permalink)
You're wrong. Radian is not unitless since Radian is an unit. The word you're looking for is "dimensionless".
And degrees is also a unit which is also dimensionless.
The only reason the derivative works better in Radian than Degrees is not because of one being a unit and the other not, but because Pi is at the heart of mathematics while 360 (an arbitrary number inherited from Babylonians diving stuff in 60 parts instead of 10 or 100) isn't.
Akijojo · 10 points · Posted at 14:42:42 on January 9, 2016 · (Permalink)
This comment made me realize how weird "an unit" sounds.
There are all sorts of units which could be dimensionless.
I could just as easily have a single unit which is the full rotation of the circle.
The advantage of using radians is that it makes (sinx)/x =1 for very small values of x, this means that it has a gradient of 1 and a derivative of cos(x).
Well 360 isn't arbitrary, it's a highly divisible number. Whereas using 2pi as a unit isn't divisible at all, and all measurements will have infinite nonrepeating digits.
Kayyam · 1 points · Posted at 22:27:07 on January 9, 2016 · (Permalink)
SI treats radians as dimensionless. When you calculate an arc length, the product of a length and an angle is a length. It doesn't always make the most sense, though.
Kayyam · 2 points · Posted at 22:26:12 on January 9, 2016 · (Permalink)
Isn't that exactly what I'm saying? Radians are dimensionless. The product of a radian by a length is obviously a length. Why doesn't it make sense?
It's probably derived from Babylonian mathematics, their number system was based on number 60, similar to how ours is based on 10. I couldn't find any hard source for how 360 came about, though.
60 is a nice number because you can divide it evenly by all the common factors, 2, 3, 4, 5, 6, 8, 10, 12, 15. Allows you to do math with integers longer even if you have to deal with division.
[deleted] · 1 points · Posted at 13:06:42 on January 9, 2016 · (Permalink)
Also 60 minutes in an hour, 60 seconds in a minute, etc.
diakked · 1 points · Posted at 14:09:51 on January 9, 2016 · (Permalink)
60 is a nice number because you can divide it evenly by all the common factors, 2, 3, 4, 5, 6, 8, 10, 12, 15.
This. 12 is magic. Same reason we have 24 hours in a day (12 am, 12 pm) and 60 minutes in an hour. 10 and powers of 10 don't divide nicely into thirds or sixths or eighths.
[deleted] · -3 points · Posted at 11:27:02 on January 9, 2016 · (Permalink)
That's related to base 60, yeah, because you have 60 minutes in hour and 60 seconds in a minute, and 1000 meters in a kilometer.
However, circle is divided into 360 degrees, and each degree is divided into 60 arc minutes, which are further divided into 60 arc seconds. You type them out 180°45'1" for 180 degrees, 45 arc minutes and 1 arc second. Minutes and seconds are in the wrong place there. I mean, it seems to relate to 60-base number system, but I can't really see any big singular reason why 360 precisely.
That's not strange. It's a very perishable skill. Most math is, but I found trig to be the most perishable. The less you use it, the less likely you are to remember it.
Well, it's not exactly the reason why. I might be getting a little Platonic here, but circumference is 2pi x r because it's just a fact that can be measured or calculated. More accurately, circumference being 2pi x r is the reason why a radian is defined the way it is.
That too, but I fully intended to write "Platonic." As in, I believe abstract numbers actually exist in the physical universe. Otherwise, it might not make sense to say that "one math thing is the reason why another math thing is". You know, people who believe math is a collective figment of human's imaginations might have an issue with that.
What's the difference between pi rad and 1/2 circumference?
Minkar · 1 points · Posted at 17:44:23 on January 9, 2016 · (Permalink)
Well, the difference is that pi radians is an angle, where as 1/2 circumference is a distance. Though they are intimately related, as an angle of pi rad (180 degrees) produces an arc which creates a semi circle, or half the circumference.
samsg1 · 7 points · Posted at 11:49:03 on January 9, 2016 · (Permalink)
I have a degree in physics.. I finally got radians. Thank you!
[deleted] · 1 points · Posted at 20:24:21 on January 9, 2016 · (Permalink)
I'm confused how you couldn't get it before
C = 2πr
so if you say there are 2π radians in a circle then the length of the arc subtended by 1 radian (ie 1/(2π) of a circle) is 2π.r/(2π) which is simply r.
C/(2π) = r
What's more helpful is that all the relationships are simplified by the 2π factor. It's just a substitution to make things easier. Look at that first equation:
C = 2πr
What are you going to pick to make this simple? That's right 2π.
[deleted] · 1 points · Posted at 20:25:38 on January 9, 2016 · (Permalink)
No
Brarsh · 1 points · Posted at 04:29:59 on January 10, 2016 · (Permalink)
Well, it's a hint as to what it is by having a similar name. The radius is used to travel that distance around the circle, and the angle that the starting point and ending point in relation to the center of the circle is 1 radian. The "pizza slice" that it makes has 2 straight sides 1 radius long and one curved side 1 radius long.
That is the biggest flaw in the education system, making you learn what the end result is and not how you get there and why. Never too late if you want to turn it round though!
Holy shit. I'm in my twenties, always excelled in Mathematics. It has never been explained to me like this but it all makes sense now! You're amazing thank you!
I'm a 25 year old man and this is the best explanation of circumference and pi that I've ever seen. Thank you so much for this. Really wish I had this lesson years and years ago.
Wait a minute. Math actually makes sense? They never told me this in high school!
boraxus · 2 points · Posted at 00:38:01 on January 10, 2016 · (Permalink)
My god. I am 39 years old and struggled with geometry in junior high/high school. A rectangle's area is the length times the height, therefor a square's area is either the height or the length squared. After seeing this, it is the first time I ever understood "(Pi)(r-squared)" and how it makes any sense. I've always just accepted it, and been frustrated not to know.
Wow too cool. I could have understood so much more with graphics like this to help my simple mind get it. (btw I still ended up aiming missiles by the stick...lol )
Your mistake is converting Pi into a decimal value. Not only is that not necessary, it actually complicates things. Just leave it as Pi. Why? Because often another Pi will pop up in your equation, and you'll either cancel it or square it. It is easier to cancel or multiply if you keep it as "Pi", and it is also much easier to write the Pi symbol than to write out 3.14159 . . .
We just use Pi and fractions of Pi, which is pretty much what you're suggesting with redefining the radian as 1/3 pi. But having an unit angle equal to unit length in circle with unit radius is very useful.
[deleted] · -1 points · Posted at 12:02:35 on January 9, 2016 · (Permalink)
Say you have a car with wheels of radius 0.5 m. The car is moving at a speed of 10 m/s. How fast is the wheel rotating?
With degrees, you gotta divide the car's speed by 2 Pi, divide by the radius (0,5 m) and multiply by 360. Try doing that.
With radians, you just divide by the radius! So, it is spinning at an angular velocity of 20 rad/s. Easy!
[deleted] · 2 points · Posted at 12:15:23 on January 9, 2016 · (Permalink)
Here's one advantage, if you define sin(x) and cos(x) in degrees. (e.g: sin(90)=1, cos(180)=-1,cos(270)=0...)
Then the derivative of sin(x) is (2pi/360)cos(x), and the derivative of cos(x) is -(2pi/360)sin(x)
On the other hand, if you define them in radians (e.g: sin(pi/2)=1, cos(pi)=-1, cos(3pi/2)=0...0
Then the derivative of sin(x) is cos(x) and the derivative of cos(x) is -sin(x)
aianus · 2 points · Posted at 12:15:49 on January 9, 2016 · (Permalink)
If given an angle in radians and the radius of the circle, then the arc length is exactly the angle times the radius.
Degrees are like inches and feet, they don't naturally relate to anything.
Radians are the distance around your circle. How much rope do you need for this circle? You need 2piR.
Don't convert to decimal ever until you absolutely need to. Think of pi as a unit like inches. So how much rope do you need to go around the circle 100 and a half times, 201piR. Had you converted in the previous step you would have a less accurate number now.
Going around a circle a half is pi, a quarter is 1/2pi generally written as fraction instead of a decimal when going fraction ways around a circle.
lucasvb · 3 points · Posted at 11:57:20 on January 9, 2016 · (Permalink)*
The point is that we need an angle unit that is inherent to the circle. Radians do that.
But the fact there are 6.283185... radians in a circle doesn't matter. The number is not important, that's why we have a constant for it (2π = τ). We don't care about it.
What we would use most of the time is a ratio of that number, so τ/4 = 2π/4 = π/2 is a quarter of a circle, and so on. That means the constant makes it human-readable, and the fact we're using radians as a unit makes it mathematically sensible.
(By the way, before someone complains, radians ARE a unit. They're a dimensionless unit, but a unit as well. A degree is also a dimensionless unit which is 1/360 of the angle around a circle, as opposed to 1/2π around a circle.)
Cerxi · 1 points · Posted at 12:35:55 on January 9, 2016 · (Permalink)
Because part of the use of it is that it is equal to the radius. If you added 1/3pi to each radian, than near every use of a radian in your equasions is going to look like "r - 1/3pi". Plus, it makes the definition of a radian from "the length of the radius, wrapped around the edge" into "the length of the radius, plus one third of pi times itself, wrapped around the edge". Neither is elegant or especially useful.
[deleted] · 1 points · Posted at 13:07:53 on January 9, 2016 · (Permalink)
Woosh. Go back to 9th grade.
(Edit: I don't know whether it's taught in schools at that age, it was in mine)
I was never taught radians in high school hence my questions and confusion but it seems like asking things is against the spirit of /r/eli5 so nevermind.
Holy crap, nobody has ever told me this! Every one of my teachers has just told me there are 2pi rads per 360 degrees and made us learn by repetition. Thank you for this!
I used that to save this comment. I'm fully aware of reddit's save feature, but windows phones are literally the foul excrement of Satan himself, and there is no comment save feature on my app.
myhf · 1 points · Posted at 15:19:12 on January 9, 2016 · (Permalink)
rad
Zadoose · 1 points · Posted at 15:23:57 on January 9, 2016 · (Permalink)
holy shit i never understood the meaning of that and have been using pi and rad for years and only til now do i know where this comes from, that was amazing
In 2d graphics programing there is no circle command, only lines and arcs, so to draw a circle you just tell the computer to draw an arc with an angle of Pi x 2.
I never understood how that worked until just now, thanks!
Nope, pi is that little bit and the others.
180 degrees is made up of 3 radius lengths wrapped round the circles arc + a little bit more. That little bit more is 1 radius length * 0.1415926535897..... and so on.
Wow. Who works this shit out? Especially Pi which only ever has an approximate value. Oh yeh, some stoned beardy togaGreeks. Anybody know what exactly they smoked back then? I want some so I can figure out all kinds of unanswered shit. Wow, some kids just built a little snowman outside my coffee shop. Oops, sorry, #shortAttentionSpan
But surely there'd have to be a number of how many radians are in pi, right? It can't go on indefinitely.. Can it? For the fourth piece of that gif once r starts going around the circle to make one pi, if it is a definitive space needed for what is supposed to be the 3+.1415..... How is it possible that to find the length it is all repeating?
If you can work that out you will get a butt-load of money as it is crazy hard to calulate, those these guys did 12 trillion and it took them 94 days of computation to do so.
It is not definite that it never repeats itself but proving that is hard as hell. In this case, you'd have to get to the infinite digit to prove it never repeats and that is impossible due to infinity being larger than everything, meaning that as soon as you get to the 'last' digit there will be even more.
Hey non-STEM person, 3 rads make up very very nearly a full half (180 degrees) of a circle.
The little bit left over is the fractional part of Pi and that is 0.14159265358979... * 1 radius length. This fraction is flipping annoying as it never repeats itself (as far as we know) and is only needed to make the whole thing work.
And there was me thinking rads were what you got for standing in poop in fallout
80Eight · 1 points · Posted at 17:01:13 on January 9, 2016 · (Permalink)
If PI Rad hadn't jumped out of no where I might understand it...
Where did that come from? What's that tiny slice called? Is a half a sphere a rad or half a circle... Is it 3.14 of a circle a PI Rad? Is that .14 the tiny amount and all the others are 1.00?
So one radian is formed by wrapping 1 radius length about the edge of a circle.
3 of these wrapped together gives you a 3 radian arc.
However, there is a little piece left and that little bit is the fractional element of Pi. So 180 degrees is half a circle which is 3 radians plus a little bit extra.
[deleted] · 1 points · Posted at 17:02:09 on January 9, 2016 · (Permalink)
As someone who has the mathematical abilities of a toddler, this gif confused the ever living shit out of me
it's worth noting that radians aren't arbitrary - an angle of 1 radian is defined by the properties of a circle rather than being an arbitrary number of slices.
well, the definition of pi as 'the number of radians in a straight line' or 'the ratio between a circle's circumference and diameter' is correct and absolutely true, so the way we define pi isn't 'arbitrary' or 'wrong'. in that video, Vihart is arguing that its use is less intuitive or practical than the use of tau. deciding whether you want to use pi, tau, or some other constant like pi/2 or pi/12 is the arbitrary part. you could argue that pi/12 (let's call it mu) is a good one because then you have 24mu in a circle, which divides up very easily into subsections (1/2, 1/3, 1/4, 1/6, 1/8, 1/12, 1/24) of the circle without having to use fractions, which some people prefer for aesthetic reasons. tau on the other hand lets you use the fraction of tau as the fraction of the circle you're dealing with. pi, also, comes up in a lot of equations without a factor of 2 (for example, the area of a circle) and is neater in those instances. so they both have advantages and disadvantages.
I'd guess that pi was preferred by people that measured diameters by hand to use in calculations. Tau is like the idealized pure version where no physical measurements will need to be done because you just specify the radius.
Yeah exactly, so it more depends on what you're doing that anything else. I like tau because of the whole fractions of a circle thing, but if I've measured a diameter, I'm not going to then divide it in half just for the sake of using it.
Pi is arguably the more pure version because of how often it comes up in mathematics. For an example, the integral of the Gaussian is the square-root of pi.
[deleted] · 0 points · Posted at 18:29:32 on January 9, 2016 · (Permalink)*
[deleted]
algag · 1 points · Posted at 18:51:45 on January 9, 2016 · (Permalink)
I don't think you know what diameter means. Lol jk. But for real, it just depends on if you consider the diameter or the radius more important. I could say that that I prefer tau because "ratio of radius to the circumference" is more intuitive than " ratio of half the diameter to the circumference "
The main reason people think that this is the case is because there are videos and infographics and everything made by people who want to push for tau, while not many serious people actually care to defend pi because of how futile it is.
I suggest you read a well-written answer to all of this noise about tau, like http://www.thepimanifesto.com/ for instance. I'd be surprised if, after reading that, you still think tau is better than pi in "just about every way".
Amablue · 5 points · Posted at 17:35:47 on January 9, 2016 · (Permalink)*
That page is not very convincing. Tau is still clearly better to me.
The main points seem to be (1) that basing our constant on the diameter makes more sense because it's easy to measure and (2) that just as many equations are made simpler by pi and that the equations that tau makes simpler were carefully selected.
I disagree with both of these points. In math, we don't measure circles, we create them. A unit circle is a circle with a radius of 1. We do all kinds of math based on a unit circle. The radius is the fundamental value that describes the circle. We should use that when making our definitions. Arbitrarily switching between radius for some thing and diameters for others only confuses the relationships between things.
The page uses as an example the area of a unit circle. They claim that tau is only more intuitive measuring angles while pi is much better for areas. This is silly, of course tau is better for angles, that's what it's measuring. They claim as an example that the area of a unit circle, pi, is beautiful and simple and thus a point in pi's favor. The result of pi is simpler, but it's not better. You've lost the relationship between the angle and the area. When you express the area in terms of tau the relationship between angle and area is preserved.
Let me expand on that a bit: Consider the case where you're trying to find the area of a circle by integration. You have the equation ∫ τ r dr, which we can integrate to find τ r2 / 2. That extra division by 2 isn't arbitrary - it's there because we have an integral. Its part of the relationship that we obscure when we use pi.
Most of the rest of the arguments are variations on the area argument - that some equations work out 'prettier' when you use pi instead of tau. The main difference between the two constants is that you end up adding or removing a 2 somewhere in your equations. In the case of tau though, those 2's are meaningful and help demonstrate relationships between various areas of math. In the case of pi, they're just thrown in and meaning is lost. It's not about what gives us simpler equations, it's about what gives us equations that demonstrate relationships and express the most meaning.
In math, we don't measure circles, we create them.
I'm not sure I agree with this, considering that I (and probably a good number of mathematicians) don't really do either, but regardless, when he makes this point, he's responding to a part of the Tau manifesto that discusses the genesis of Pi in ancient Greece, and clearly Greek mathematicians were interested in measuring things (including "circles", e.g. here).
Let me expand on that a bit: Consider the case where you're trying to find the area of a circle by integration. You have the equation ∫ τ r2 dr, which we can integrate to find τ r2 / 2. That extra division by 2 isn't arbitrary - it's there because we have an integral. Its part of the relationship that we obscure when we use pi.
I don't get where you're going with that. If you have two quantities, one of which equal to tau=2pi, one of which equal to tau/2=pi, and there is a way to go from the first to the second to "justify" the factor 1/2 in tau/2 in the second quantity, then it also explains the factor 2 in the 2pi of the first equation. It's just a matter of point of views.
In the case of tau though, those 2's are meaningful and help demonstrate relationships between various areas of math. In the case of pi, they're just thrown in and meaning is lost.
All of that only holds based on the assumption that tau is a better constant. You're not adding another argument in favor of tau by saying that: you're just restating that you think it is better.
It's not about what gives us simpler equations, it's about what gives us equations that demonstrate relationships and express the most meaning.
Well, I find more meaning in writing the Gaussian integral with pi than with tau. Same things with the links between the Gamma function and pi or tau. Same with Euler's identity (I mean, "exp(i*pi)=-1, therefore exp(2*i*pi)=(-1)2" is nice, while you lose something if you try to start from tau by saying "exp(i*tau)=1, therefore exp(i*tau/2)=±11/2). And I really think that having simpler expressions is a good thing: readability is probably just as meaningful as having the best content, if you're trying to teach math.
Amablue · -1 points · Posted at 18:55:37 on January 9, 2016 · (Permalink)
I don't get where you're going with that.
The integral of x is 1/2 x^2. Whenever you see that form come up in an equation, that's a big hint that you're looking at an integral.
There was this great moment for example when I took both physics and calc in college where we were looking at an equation for moving objects, y = 1/2 a t^2 + vt + x, and I thought to myself "Man, that really looks like an integral". Just a few days later, we did the integral that produces that equation, which connected those two concepts in my mind.
The form of the equation can be used to carry meaning. It demonstrates the relationship. The 1/2 a t2 is an integral, which is why it has the same form as 1/2 τ r2. That 1/2 isn't arbitrary, and it's not better to just remove it. It connects the concept of the area of a circle to the concept of the integral of x.
I'll post more later, I have to head out and take care of an errand.
You do know Vi Hart is a serious mathematician, right? I think most mathematicians would agree that Tau would probably be the better fundamental constant, but don't make it their vendetta. However, it would make teaching trigonometry so much easier, that I think math educators should care a ton about the distinction.
[deleted] · 14 points · Posted at 16:11:35 on January 9, 2016 · (Permalink)*
You do know Vi Hart is a serious mathematician, right?
What? According to herself she's a "recreational mathemusician". I'm talking about actual mathematicians, you know, the ones who work in a university or a research institute. As far as I'm aware, she isn't. I'm not saying I don't like her videos or anything -- but she isn't a serious mathematician anymore than the guys from mythbusters are serious physicists or serious chemists.
I think most mathematicians would agree that Tau would probably be the better fundamental constant, but don't make it their vendetta.
I'm a mathematician (I work at a university and I'm paid in part to produce mathematics research, something that occupies a very large part of my awake time, in case I really need to make clear what I mean by that...), and I don't think that. The topic has come up a few times talking with my colleagues, and no, they simply think (like me) that the whole tau thing is silly, that it wouldn't change anything at all to mathematics, and it's not worth wasting time about. It's my impression that it's the general sentiment among mathematicians everywhere, though there are probably exceptions somewhere.
However, it would make teaching trigonometry so much easier, that I think math educators should care a ton about the distinction.
It's not even clear that it would make teaching trig any easier. If you want, here's a Q&A at matheducators.SE, it's mostly people with actual interest in math education (as opposed to armchair math educators). Here's the pi manifesto too. As for myself, I simply don't care. Pi is the standard, and the minute benefit (if any!) gained by changing are not worth the notational upheaval.
She publishes regularly, which seems substantially more relevant than who signs her paychecks. You wouldn't say James Simons isn't a mathematician because he makes his money at a hedge fund.
I think most mathematicians would agree that Tau would probably be the better fundamental constant
When I was in high-school and didn't know any higher math, I thought tau was the shit -- I told everybody about it. Now I'm currently in my senior year of an undergrad math degree, and it's honestly a meaningless debate. If you tried to bring up this debate in the math department, you'll get eyes rolled at you.
I'm not trying to discredit those who have sparked this debate, because it's good that math is getting a little bit of spotlight in popular culture. I probably wouldn't have decided to major in math had I not been exposed to popular math first.
As for the education aspect of it, mathematics is as much tradition as it is rigor. A good mathematics educator, in my opinion, would teach the history of mathematics along with the lesson plan, particularly in a geometry class. Using pi over tau is far from the problem why students have trouble understanding trigonometry. The problem is that many good educators do not bother to go into K-12 education (at least in the US), because the US does not respect the teaching profession.
I think most mathematicians would agree that Tau would probably be the better fundamental constant
I consider myself a young but somewhat serious mathematician (published in several good journals in my field of study), and I disagree. Of course, if tau had been the constant forever, and people were pushing to make pi the new constant, I'd find it pointless too. But still, I prefer pi over tau regardless of the history of things.
People who advocate for tau tend to pick examples that they like, mostly from very basic math. That makes sense because they want to reach a greater public, but it's also a bias as their arguments hold much stronger there than if you also consider broader topics (series, probabilities etc). http://www.thepimanifesto.com/ summarizes that pretty well.
But to be fair, one of my major concerns is that when manipulating pi, you encounter a lot of nπ, 2π, 2π/3, π, π/2, π/3, π/4, π/6, π2/6 etc. Write these expressions with tau instead, and you get nτ/2, τ, τ/3, τ/2, τ/4, τ/6, τ/8, τ/12, τ2/24. Out of these common examples, only two are (slightly) simpler with tau: τ instead of 2π, and τ/3 instead of 2π/3. However, most are more annoying to write with tau, including in some cases having to write a fraction where there wasn't one when we used pi. Of course, people doing math in different domains are going to encounter all of these expressions with varying frequencies, but in my experience, the only domains in which you see "2π" so often that abbreviating it into "τ" counter-balances the scenarios in which using pi makes an expression simpler to write (and potentially removes a fraction) is when you're working with Fourier transforms, or in general when you use exp(2πi) a lot, and in that case, your meaningful constant isn't 2π, but 2πi, meaning that tau isn't the appropriate choice here either.
narp7 · 5 points · Posted at 17:15:59 on January 9, 2016 · (Permalink)
This doesn't show that there's anything wrong with pi, or that it's arbitrary. Pi is not an arbitrary value at all. To claim that it's arbitrary is demonstrably false.
This is just someone who is bad at math ranting because there are 2pi in a pie and not one, as someone with no mathematical background at all would guess.
Seriously, she bakes a pie and then is upset when 1/4 of the pie, is not 1/4 pi radians. Well no shit. No one decided what a radian was. That's the natural unit!
Basically, this video is the dumbest shit I've seen all day. It's a video by ignorant people, for ignorant people. It's like a circlejerk of people celebrating how bad they are at math, then trying to say that because they don't understand it, it doesn't make sense.
There is nothing wrong with the concept of pi. You just can't assume that there is 1pi in a cherry pie. I'm sorry, but math is not based around the convenience of cherry pies.
She's a mathematician, she understands the principles just fine. Vihart is proposing that tau is better than pi, because many people find it easier and more intuitive to learn. Half a circle is 1/2 tau, very straight forward.
Using pi as the basis is because humans started with physical round objects and then created mathematics to suit. You can measure the diameter and the circumference of a pipe, and therefore you can determine the ratio pi. However, if we started with mathematics as the basis there is no doubt tau would be the logical choice since the radius of the circle is the primary feature and used much more frequently throughout math and engineering.
ivalm · 2 points · Posted at 21:42:34 on January 9, 2016 · (Permalink)
VI Hart is a YouTube educator, not a mathematician. She hasn't done much meaningful mathematics research, heck, she only studies as an undergrad. As someone coming from physics (as in science, not an undergrad taking classes), and having worked and know people who work in theory (again, as in science, not cool YouTube demonstrations for general audience) I really don't know any serious person who has a preference for tau over pi. The entire discussion is a joke. They are equivalent and since pi has been around longer switching from it would just introduce unnecessary confusion.
Completely agreed that switching from pi to tau would be a difficult process and not worthwhile, but I definitely think using tau would make trig easier for the average student.
Soviet army used 6000 standard. Russian Wiki says it's for the quickest divisibility and for quickly estimating angles in mils in the field directly from distances in your head. Then, if you want to raise the precision for particular tasks, you throw in a 5% offset. The traditional military name for this unit is "thousandth" (тысячная).
[deleted] · 1 points · Posted at 19:28:13 on January 9, 2016 · (Permalink)
Has to scroll down a long way to find mils mentioned...I spent some time doing survey for the artilley...Loved the fact that the main thing I surveyed for was radar that only needed to be roughly sighted in, considering that our measurements were down to .05 mils (less than .003 degrees).
zilti · 11 points · Posted at 14:14:54 on January 9, 2016 · (Permalink)
We use 6400 in the Swiss military as well, it's called "Artilleriepromille" (artillery per-mille)
Just yesterday I was wondering why we used such a fucked up arbitrary segmentation of a circle and didn't use decimals of degrees. Now I know it isn't arbitrary. Wow.
bejean · 1 points · Posted at 15:35:44 on January 9, 2016 · (Permalink)
Mils are great for optics because of the small angle approximation: for very small x in radians, sin(x) ~= x.
If you have a scope marked in mils and you see and adult that is 2 mils tall in your scope, you can estimate that they are a kilometer away. Sin(.0002) ~= .0002 = height of person/distance, and adults are ~2m tall.
dropping shells... adjust aim 10 mils to the right
This won't work, adjusting left or right is going to change the azimuth to the target less then that, and it will also change the range some.
Think of a circle, and the point you hit is on the circle. If the point you intend to hit is 100 meters to the right of it, it may be the same distance as 10m on the circle, but it doesn't follow the circle, the new point is either ahead of or behind it, depending on the perspective of the observer.
Even if it was that simple nobody would ever do it because they don't want to be the guy to say 'ah forget a new firing solution we can just fire the same mission again but adjust the deflection by 10m' because he is the guy who is going to be in deep shit if the round hits a walmart parking lot.
I have a Mils compass. Wasn't aware of the specific attributes you've described here. I just thought it meant you didn't have to talk in fractions so soon!
I should add that the Radian is the natural unit of angles - if you use degrees, you'll get factors of 360/2π (or its reciprocal) everywhere, for example in calculus. They are the only non-arbitrary unit.
It's the ratio of the length around the arc, to the radius, for a given segment. Since a circle has a circumference of 2πr, you get 2π radians in a circle.
The radian is of course not arbitrary. It is actually a rather natural way to measure the curvature of things which does not vary with the size of the thing being measured.
And (I have been told) that 360 was chosen because there are so many dang ways to divide it evenly. 360 is divisible by your friends 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20... it goes on.
Good to know this. In grade school one time when I first learned about this 360 degree crap I actually caused a scene because I thought it was so fucking stupid.
[deleted] · 1 points · Posted at 17:14:56 on January 9, 2016 · (Permalink)
TIL 5 year olds could understand this.
How does this get so many upvotes lol it has nothing to do with this sub.
Just like to add that the 360 came from the ancient egyptians, who believed the sun completed one full rotation around the earth in 360 days (they were only off by 5 days or so, also by the sun not actually moving around the Earth).
And so they saw the number 360 as the number of the full rotation. In other words its totally arbitrary.
Radians are a mathically consistent manner of dividing a circle, but also useless in colloquial terms. A 90 degree angle, a 180 turn, a 360 flip, a 540 snowboard move.... These are terms radians have a hard time replacing.
I purchased a compass at a flea market many years ago that was divided into 400 parts. I was told by some WW2 vets that it was a "gunnery compass". I don't know if that's true but it made sense to me, especially if you were training people without a math background; "0" is behind me, "100" is on my right, "200" is in front of me and "300" is to my left.
[deleted] · 1 points · Posted at 19:05:01 on January 9, 2016 · (Permalink)*
As a programmer this is often annoying because we're used to thinking most of the time in degrees but many libraries use radians. So it's always "here, I'll use degrees" and the result is a mess.
emdio · 1 points · Posted at 19:50:10 on January 9, 2016 · (Permalink)
Well, it's arbitrary in the sense that could exist -and of course exist- other ways to divide a circle, but calling it "arbitrary" is a bit unfair IMHO. For example;
[deleted] · 1 points · Posted at 01:35:01 on January 10, 2016 · (Permalink)
If it's of further interest, there has been debate about replacing 2Pi with Tau (which looks like a T), because a circle being 2 of something is notoriously confusing for students to learn. Think of how easy it is for anyone to imagine 90, 180, 270, 360 degrees. Yet even as a 2nd year undergrad who has used them for years, 3/2 Pi radians doesn't naturally or immediately mean anything to me, and when it does it's normally because I've converted it quickly to degrees in my head. So yeah. :)
The Babylonians used a base 60 numeral system because 60 was easily divided by most everyday numbers, and is why a minute has 60 seconds, an hour has 60 minutes, and a circle is most commonly referred to as 6 x 60 degrees.
You also need, at a minimum, a time and energy or mass unit to form a unit system. I wonder how long Oliver Smoot can hold his breath and how much he weighs.
RotWS · 1 points · Posted at 03:14:39 on January 10, 2016 · (Permalink)
And finally I know what the hell the grad button on my calculator does.
If not doubling a variable makes it much easier you should reconsider doing anything with math ;)
There is a genuine movement to remove pi from mathematics and engineering. It's based on the cherry picking of certain formula to suggest that τ is a "more natural" constant. However, the movement has gain recognition among serious mathematicians due to the only benefit of writing one symbol rather than two is "a saving of ink."
If you look at the circumference of a circle, the unit circle has a radius of 2π or τ. τ may appear more "natural" in this case. However, when you consider the area of a circle, a unit circle has an area of π or τ/2 making π appear more "natural". There is no way to get rid of the factor of two from the nature of π, because it relates to both the circumference and the area of a circle. Any attempt to suggest otherwise is just cherry picking of formulae.
However, when you consider the area of a circle, a unit circle has an area of π or τ/2 making π appear more "natural".
A circle of radius a has area:
int(int(1 * r dr dtheta)), with bounds of r from 0 to a and theta from 0 to {2pi or tau}.
Call the upper bound of theta k.
This isn't to say tau is better than pi, but the derivation "naturally" includes a factor of 1/2. One can choose the circle's proportionality constant to cancel with it, or one can leave it as is. The very idea of "better" - or even, as used here, "natural" - is subjective. It ties into the same question as what really counts as "simplifying."
It seems to me that, more than favoring pi or tau, we should be happy recognizing that the mathematics of circles doesn't change regardless of how one chooses to express the relationships. However, and for the record: Section 3 of the Tau Manifesto addresses precisely this issue, with Section 5 offering an extension for those with the chops.
TL;DR The beauty of math is that it doesn't really matter. That said, the example of a circle's area does not support your point.
[deleted] · 1 points · Posted at 13:31:57 on January 9, 2016 · (Permalink)
There's nothing wrong with tau, either. Getting up in arms either way is what's ridiculous. It's just a fun discussion which helps emphasize that mathematics is valid without regard to one's choice of expression and that there are often interesting connections across seemingly disparate areas.
It is, however, possible to offer arguments which are themselves flawed, regardless of which form of the constant one intends to support.
[deleted] · 0 points · Posted at 13:40:07 on January 9, 2016 · (Permalink)
All I know is I've never heard anyone say "I'll have a delicious slice of half-Tau."
It's not cherry picking. Take any formula that uses π and you'll find that it's more logically explained by using τ.
For the disk's area for instance (apparently the only counterexample that exists), if you derive its formula, you naturally get the 1/2 the same way you get it in e = m*v2/2 in physics.
[deleted] · 10 points · Posted at 12:28:01 on January 9, 2016 · (Permalink)
interesting fact, if you replace the word "logically" with "elegantly" in the above argument it's STILL not a mathematical one.
[deleted] · 0 points · Posted at 13:26:47 on January 9, 2016 · (Permalink)
Some formulas for areas or volume work better (as in, fewer constants) with pi, e.g. the area of a circle.
You don't "naturally get" the 1/2 at all. You're just putting Tau as your integration limit instead of 2π and saying it's natural that's completely ridiculous. Why is energy a gold standard for functions proportional to a squared power?
Additional counterexamples:
*Integral from -infinity to +infinity of e-x2 - you'd have some constant inside the root aswell as the π
*Oh yeah, you also ruin eulers formulae with a nasty fraction of 1/2 or lose the minus sign - often called the most beautiful equation in mathematics
Seriously the decision is arbitrary and it's really not worth arguing, it would be an unbelievably ridiculous decision to change it.
Although for my 2 pence go team π purely because it ruins Eulers identity.
Edit: The reason I prefer eulers with -1 is because it's another layer of abstractness in the formulae, the concept of negative one things isn't amazingly intuitive in the same way as i and pi aren't. That's why I think it's neater.
You don't "naturally get" the 1/2 at all. You're just putting Tau as your integration limit instead of 2π and saying it's natural that's completely ridiculous.
I did it with khere. You do get a factor of 1/2, thanks to the integration of r with respect to r. Whether it's "natural" to keep that factor independent or to want to simplify is subjective, but the factor does appear without regard to the use of pi or tau as a bound.
The whole beauty of math is that it doesn't really matter. It's all valid regardless of how one chooses to express the constants. The example of a circle's area, however, doesn't support the claim.
Whilst I agree by the same logic you could argue a 1/3 is "natural" for a sphere because of the dependence on a2 being integrated. I'm going to stop with this now because it's, as you said it doesn't really matter and it wasn't even you I was arguing with!!
Thanks for spending the time to chat!
[deleted] · 0 points · Posted at 12:26:07 on January 9, 2016 · (Permalink)
it's pretty easy to use tau in your math paper, just write at the top
No. The "heart" of mathematics is that it doesn't make any difference whether you choose to express relationships with pi or with tau.
Social inertia is not a valid mathematical reason for not altering something.
Subjective determination of elegance is not a valid mathematical for altering something.
The meaningful purposes of the discussion are (a) to further understanding of connections among apparently different approaches or results and (b) to better solidify understanding that mathematics' validity does not depend on the symbols used.
You'll also realize that 4pi crops up a bunch. Oh no! Now it's 2tau.
Seriously, changing which one is the 'mainstream' constant is more trouble than it is worth, mostly because it isn't worth much.
MPixels · 2 points · Posted at 12:10:53 on January 9, 2016 · (Permalink)
I wasn't proposing we overhaul mathematics to replace Pi. Just pointing out it'd be simpler if Babylonian mathematicians had arrived at Tau in the first place.
Kayyam · 3 points · Posted at 13:04:59 on January 9, 2016 · (Permalink)
Babylonians didn't arrive at Pi and radians. They are the one responsible for the 360 degrees clusterfuck though.
MPixels · 1 points · Posted at 13:30:23 on January 9, 2016 · (Permalink)
They were calculating using an approximation of Pi first.
[deleted] · 2 points · Posted at 13:33:05 on January 9, 2016 · (Permalink)
Just because one appears more than another does not mean it's the fundamental. Not by any stretch. In fact, they define each other on an equal unit basis, meaning they are equally as "fundamental" as each other.
I'll explain - the units of Energy are J = kg·m2·s-2 . I can define the kilogram, therefore, as kg = m2·J·s-2 ... but this does not make the Joule (J) a base unit.
In my current line of study, Joules come up much more than Kilograms. Base unit? Nope.
MPixels · 1 points · Posted at 13:55:09 on January 9, 2016 · (Permalink)
What I'm saying is that it's the difference between having grammes or kilogrammes as a base unit. The latter was chosen because it was simpler that way and you didn't have to multiply by a thousand all the time.
Yes, but there aren't 6 other equivalents to work with when we're talking about radians. In fact, the kilogram is more an issue of naming convention - it already existed pre-SI.
MPixels · 0 points · Posted at 14:25:35 on January 9, 2016 · (Permalink)
sigh I know... we're not really communicating properly here so nvm
[deleted] · 0 points · Posted at 12:29:11 on January 9, 2016 · (Permalink)
not sure what you've got yourself there is an argument. what does funamental mean?
MPixels · 0 points · Posted at 13:29:39 on January 9, 2016 · (Permalink)
Fundamental: "Forming the necessary base or core"
[deleted] · 1 points · Posted at 13:43:37 on January 9, 2016 · (Permalink)
sooo, if tau is fundamental and 2 is fundamental, then pi is fundamental because tau=2 pi and pi=tau/2
MPixels · 1 points · Posted at 13:52:56 on January 9, 2016 · (Permalink)
That's not how it works...
[deleted] · 1 points · Posted at 14:55:20 on January 9, 2016 · (Permalink)
well you were the one who defined fundamental as being "the core" or something. I took that to mean generators of some set under the standard arithmetic operations. pi and tau generate the same set, so they are equally fundamental.
[deleted] · 1 points · Posted at 14:57:12 on January 9, 2016 · (Permalink)
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[deleted] · 1 points · Posted at 16:47:55 on January 9, 2016 · (Permalink)
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[deleted] · 2 points · Posted at 16:57:42 on January 9, 2016 · (Permalink)
However, if you consider the visual part of things, sticking with π is much better than replacing it with τ. T and t are very widely used for other things, and both of them are visually similar to τ. However, π has no other closely similar common symbol, unless you count n. And I have never seen anyone confuse a π with an n.
I'm surprised you didn't mention computer programmers. Most standard math libraries have abandoned degrees at this point. Radians are far simpler to work with. The only reason people find them confusing is because they are taught degrees first and have that cemented in their minds before being exposed to radians. I teach some young children (grad 5-9) math, programming and some trig. The younger ones have absolutely no issue with radians. It's much more intuitive that turning around would be 1pi than 180 to them.
Yes, it's arbitrary. But very convenient since 360 = 2 x 2 x 2 x 3 x 3 x 5 (prime factorization) so that it's divisible by 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360 (yes, that's 24 divisors!). That is, if you divide a circular disc into 1, 2, 3, 4, ..., 90, 120, 180, 360 equally large sectors all of them will have an integer angle measured in degrees: 360, 180, 120, 90, ..., 4, 3, 2, 1 degree(s), respectively.
For comparison, if we divided a circle into 100 degrees, which is 2 x 2 x 5 x 5, it would only be divisible by 1, 2, 4, 5, 10, 20, 25, 50, 100 (which is only 8 divisors) giving us significantly fewer options.
It's arbitrary in the sense that the only reason 360 was used is that is has so many divisors (and isn't too large). And wasn't it the Egyptians (based on the Mesopotamians' base 60 system) that invented the 360-degree circle? (I mean, used by us today.)
Indeed, but one must also take into account that 360 is a larger number than 100.
[deleted] · 60 points · Posted at 12:56:08 on January 9, 2016 · (Permalink)*
Mils is another division. 6400 mils to a circle which is what the us army uses in some circumstances and has a beautiful relationship when relating to meters at distance so that 1 mil at a distance of 1km has a length of 1 meter and 2 meters at 2 km and so on.
Edit: 6400 mils. 1600 to a 90deg angle
[deleted] · 27 points · Posted at 13:14:16 on January 9, 2016 · (Permalink)
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[deleted] · 6 points · Posted at 13:44:35 on January 9, 2016 · (Permalink)
I forget what the soviets used for their mils, and I'm too lazy to google, think it was 6440 or something. Had to briefly learn it when teaching the d-30. Until I was taught it I had no idea what the reticle pattern in binos was for and can't believe pre22 he old me never thought to ask.
[deleted] · 4 points · Posted at 14:16:29 on January 9, 2016 · (Permalink)
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[deleted] · 5 points · Posted at 15:23:14 on January 9, 2016 · (Permalink)
Soviet Union used 6000, which makes sense, as their artillery was inherently less accurate and designed for barrages rather than precision. Lot of FIFI
[deleted] · 2 points · Posted at 18:10:15 on January 9, 2016 · (Permalink)
Unrelated, but I got to be part of a battery laid using the stars, supposedly through a method taken from some old Soviet manual. It was kinda neat.
[deleted] · 1 points · Posted at 14:48:45 on January 9, 2016 · (Permalink)
The AFATDS computes with the exact mil relation? I thought we used 6400 IOT bump with charts?
[deleted] · 1 points · Posted at 16:10:29 on January 9, 2016 · (Permalink)
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[deleted] · 2 points · Posted at 18:08:06 on January 9, 2016 · (Permalink)
That doesn't make sense, though. No one on the gun line cares about the actual value of a mil. To us, it's just a measurement - a little more convenient than degrees due to the size of the unit, but that's it. And with all of the redundancies and safety measures, why risk problems caused by defining a word two different ways?
I'm doing a service to point this out every time I see it in this thread. I only just learned this.
maladat · 2 points · Posted at 23:52:20 on January 9, 2016 · (Permalink)*
6400 mils in a circle is an approximation used to make certain types of ranging math easier to do in your head.
There really are 6283.185307.... mils in a circle, because "mils" is short for "milliradians," or thousandths of radians.
There are 2PI radians in a circle. There are 2000PI mils in a circle.
Also, the relationship you mention doesn't really have anything to do with meters at all. Being a thousandth of a radian, a mil subtends an arc 1/1000th the radius of the arc.
You gave the relationship of 1m at 1km (1000m), but it works for any units.
1 cm at 1000 cm. 1 foot at 1000 feet. 1 parsec at 1000 parsecs. All one mil. Units don't matter.
Aren't mils that line marks on long range weapons scopes?
qwopax · 1 points · Posted at 20:34:36 on January 9, 2016 · (Permalink)
Hah! The imperial mils is much easier, that's 1 foot at 1 mile. There's 33595 imperial mils to a circle, which is more natural than your arbitrary value.
More seriously, I would expect 2000∏ = 6283 mils to a circle. Your meter is actually 98cm, close enough that ease of use trumps precision.
Mils ftw. I'm sure there are a bunch of specialised reasons for the number. To me it just means you don't have to talk in fractions. Regular rads and you're expressing fractions of degrees as soon as you step beyond NE / SE.
It is arbitrary, but 360 is a number with a lot of factors so it is easy to divide.
For something less arbitrary radians are often used in mathematics/scientific applications, the whole circle is 2pi radians, which meshes well with the trigonometric functions (cos, sin, etc).
There's a slight difference between the mathematical usage of "arbitrary" and the everyday usage of that word. Mathematically, "arbitrary" typically means something like "can be changed without any real consequence: it's a human construct, not a fundamental mathematical fact".
Examples of mathematically arbitrary things are the fact that we use base 10, the fact that there are 360 degrees in a circle, and the the order of operations (BEDMAS/PEDMAS/whatever you call it). Examples of things that are not mathematically arbitrary are things like the Pythagorean theorem (in a right triangle, the sum of the squares of the two short sides equals the square of the length of the third side), the fact that pi is transcendental, and the fact that you can't square a circle.
Visell · -4 points · Posted at 17:36:06 on January 9, 2016 · (Permalink)
you can't square a circle
Tell that to fat nerds
[deleted] · -1 points · Posted at 15:43:11 on January 9, 2016 · (Permalink)
Degrees comes from old sailing navigation a degree is how much the stars would shift in a day or something like that. 360~365
On one hand, count the lines of your fingers with your thumb. 3 on each finger, 4 fingers
3x4=12
Each time you count all the lines, put up one finger on your other hand. 5 fingers, 12 lines, 5x12=60.
This is the 60 base counting system, and it was used by the babylonians/sumerian civilizations, and was adopted by a lot of math 'cults' from a long time ago.
60 minutes/hr
60 seconds/minute
ELI5: Ancient math wasnt based on 100, we did that because modern civilzations connect to it better because we count like barbarians using one finger per count and top out at 10. If you counted using a 12/60/144 based systems, we would be asking why metric is 10 based.
I never considered that method of counting, gonna use that now.
beeeel · 40 points · Posted at 16:00:06 on January 9, 2016 · (Permalink)
Try binary counting. By using each finger as a binary bit (0 when down, 1 when up), you can count to 1023 (210-1) using both hands. One hand will get you to 31.
[deleted] · 7 points · Posted at 19:18:39 on January 9, 2016 · (Permalink)
And now I am trying to binary count using knuckles. This will not end well.
Pretty hard to move all knuckles arbitrarily because of how they are articulated... but its fairly easy to have at least 4 positions (2 bits) per finger. Therefore 20 bits across both hands.
beeeel · 9 points · Posted at 20:25:20 on January 9, 2016 · (Permalink)
Put out your left hand, palm down, all fingers curled up. You thumb is worth 1, your index finger is worth 2, your middle finger is worth 4, your ring finger is worth 8, and your little finger is worth 16.
To represent 1, you just put your thumb up. For 2, you put your index finger up and thumb down. For 3 it's index and thumb. For 4, it's just middle finger.
By adding the fingers together it's possible to make all the numbers from 0 to 31 with a single hand. If you use both hands, then the first finger on the second hand is worth 32 (twice 16), and the second is worth twice that, until the last finger is worth 512.
This is exactly the same way that written binary numbers work- the furthest right digit represents 1, and then the next one on the left is 2, then 4, etc. It's not dissimilar to how decimal (normal numbers) work- the digit to the left of the decimal point is how many times 100 (1) you have, the next number is how many times 101 (10) you have, then 102 (100) and so on.
TLDM · 1 points · Posted at 20:34:50 on January 9, 2016 · (Permalink)
You can kind of do this in base 3 as well, if you can think of a decent way to represent adding and subtracting a digit (e.g. adding could be finger up, subtracting could be finger half up? That's quite difficult to do though...). You can go from -29594 up to 29594 on two hands with this method - but it's slightly useless. Still, an interesting concept.
beeeel · 1 points · Posted at 20:48:29 on January 9, 2016 · (Permalink)
It's unlikely that you want to subtract, anyway, since you're normally either counting up or down- do you could make it to 59048 with both hands, or 19682 with one.
But realistically, you're not going to do addition/counting beyound a few hundred on your hands, are you?
TLDM · 1 points · Posted at 21:08:57 on January 9, 2016 · (Permalink)
Not with base three - either you need one way to show adding and one for subtracting, or one way to represent a 1 and another to represent a 2.
But yes, this is a bit ridiculous.
Lanaru · 0 points · Posted at 18:33:02 on January 9, 2016 · (Permalink)
Glad to see someone mention the Babylonians here. While the use of dividing up a circle into 360 degrees is arbitrary today, there was a reason for its origins.
This. And to expand on how a circle was conceptualized in terms of sixty, a circle can be divided into six equilateral triangles. Each triangle has 180 degrees, with the center of the circle at the center of the points of six triangles.
The angles of the six triangles that are at the center are six times sixty.
Barbarians? I was sure we used base 10 to allow decimal math. Would decimals even be possible in base 60?
[deleted] · 9 points · Posted at 17:30:15 on January 9, 2016 · (Permalink)
Numbers after the decimal point simply represent fractional numbers. For instance, 0.124 means 1 of 1/10 plus 2 of 1/100 plus 4 of 1/1000. We could just as easily do this in any base.
In base 60, we would just have to use powers of 60 for the fractions. In fact, we could write some numbers as exact decimal points in base 60 that we can't write in base 10. For instance, 1/30 is 2/60 = .2 in base 60 expansion, while it equals .03333... in base 10 notation.
Technically, we wouldn't call them "decimals" though, since decimal literally just means ten or one tenth.
[deleted] · 0 points · Posted at 19:05:51 on January 9, 2016 · (Permalink)
Of course. Do you think math would be impossible if we had evolved with 12 fingers? Or 16? 10 is completely and utterly arbitrary, mathematically speaking.
No, base 10 isn't easier. It seems easy just because you're used to it.
In fact, base 12 arithmetic is easier than base 10. In base 10, it's easy to remember the multiples of 5 because they all end in 0 or 5 (e.g. 10, 15, 20, 25, ...). That's because 5 is a factor of 10. Now 12's factors are 2, 3, 4, and 6, whereas 10's are only 2 and 5. That means base 12 has a whole lot more numbers that are easy to multiply and divide than base 10.
Of course, there's a tradeoff. 24 has even more factors than 12, but memorizing a 24 x 24 sized multiplication table probably isn't worth it.
horneke · 1 points · Posted at 00:28:23 on January 10, 2016 · (Permalink)
Base ten. When you switch base numbers, your digits change. In base twelve, 12 becomes 10, 144 becomes 100, etc. You just need more, or less, digits depending on what base you are using. Binary is another example where 10 doesn't equal ten.
[deleted] · 1 points · Posted at 03:04:08 on January 10, 2016 · (Permalink)
No, for serious... It's only because we're used to it. And we're used to seeing the digits 0-9. But if you here up with 12 squiggly digits, or 8, or 16, you would think it just as easy, and math would work the same. Multiplication, fractions, it would all basically be the same.
Or do you think we just coincidentally hit on the exact right number of fingers to have to make universal math easier?
No, I think that we used many different bases as needed, but that for modern accounting to take off, base 10 was settled on. (I mean, our verbal language even has unique numbers to 12 before going into a pattern, so it isn't about fingers at all, in any way)
[deleted] · 1 points · Posted at 15:25:31 on January 10, 2016 · (Permalink)*
I'm really having difficulty understanding how you're not understanding this, with several different people telling you that's simply not the way things are.
for modern accounting to take off, base 10 was settled on.
You're simply making up whatever comes into your head, but that isn't the way history works. What evidence do you have for this assertion, or does it simply "feel right" to you, based on a few comments you've read in this thread?
Great, you heard that the Babylonians had a base-sixty system. Are you aware that they actually counted their values below sixty in bundles of ten? And that all our records of counting for thousands of years before them were in base-ten? That there is no ancient Indoeuropean counting system that doesn't involve sets of ten?
Unique names until 12 has nothing to do with what you think it does. No Indoeuropean system was base-twelve, even in words. The words for eleven and twelve come from Proto-Germanic *ainlif and *twalif (respectively one left and two left), both of which were words using a decimal notation.
And you still seem to be failing to understand the basic point: do you really think it's a coincidence that we evolved ten fingers -- which even you must understand had nothing to do with counting -- and the fact that all ancient counting systems involve bundles of ten?
Nor have you given any evidence of your assertion that base-ten is easier for modern accounting than base-eight or base-twelve would be, had we evolved with eight or twelve fingers.
Yup. Completely arbitrary. The Sumerians and Babylonians used a sexagesimal counting system, or base 60 (as opposed to our decimal, base 10, system). They said a circle could be divided into 6 60-counts, or 360 degrees, and we have stuck with that since.
That's also why we have 60 minutes in an hour and 60 seconds in a minute.
Cool thing to know: Thats also the case why much languages have specific names for 11 and 12 (eleven,twelve,onze,douze,elf,zwölf) if you want to know more just google: "duodecimalsysten".
I've heard the reason 360 was chosen is because in history it was thought it took 360 days to circulate the sun. Wound up being 5.25 days off.
[deleted] · 31 points · Posted at 09:36:41 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 67 points · Posted at 12:44:22 on January 9, 2016 · (Permalink)
Arbitrary means based on randomness or whim rather than any reason or system.
Arbitrary and random are two completely different things, and while something surely can be arbitrary if it's random or whimsical – the opposite often isn't true.
In essence, "arbitrary" can be thought of as "for any or no reason".
Example: When asked my favourite number, I answer 17 because I think it's the best number. I've always liked 17 the most, so it's not whimsical. I'll also always answer 17, so it's not random. It is, however, arbitrary.
hirjd · 1 points · Posted at 18:17:00 on January 9, 2016 · (Permalink)
I choose 30. The average of 29 and 31, both prime. Also the average of 23 and 37, next pair both prime. And it's like that for 5 pairs of primes. A small number for such a claim.
No, arbitrary isn't for any reason. If so you could say any decision at all is completely arbitrary, as they exist for some reason or it is made for no reason.
Something which is arbitrary is something which is decided randomly, at a personal whim, or otherwise such that though it may make sense for the person who decides it appears random or whimsical to others. The comment you are replying to more closely captured the definition then your own, though your example hits it right on the head. You had a reason for choosing 17 as your favorite number and maybe even one for considering it the best number, but to anyone else it seems like a random or whimsical choice.
choosing 360 is so that it is divisible by 2,3,4,5, and 6.
Very important when dividing a pizza with friends.
[deleted] · 2 points · Posted at 14:41:10 on January 9, 2016 · (Permalink)
arbitrary means based on randomness or whim rather than any reason or system
According to who? Your own personal dictionary that nobody else uses? In this day and age I'm baffled that someone can dare make such blatantly wrong statements without even checking in an online dictionary or something like that... Here's what "arbitrary" means according to Merriam-Webster:
Full Definition of arbitrary:
depending on individual discretion (as of a judge) and not fixed by law <the manner of punishment is arbitrary>
a. not restrained or limited in the exercise of power : ruling by absolute authority <an arbitrary government>
b. marked by or resulting from the unrestrained and often tyrannical exercise of power <protection from arbitrary arrest and detention>
a. based on or determined by individual preference or convenience rather than by necessity or the intrinsic nature of something <an arbitrary standard> <take any arbitrary positive number> <arbitrary division of historical studies into watertight compartments — A. J. Toynbee>
b. existing or coming about seemingly at random or by chance or as a capricious and unreasonable act of will <when a task is not seen in a meaningful context it is experienced as being arbitrary — Nehemiah Jordan>
I highlighted the definition that I think is the most relevant here. There's nothing intrinsic about 360°, but we chose it because it's convenient. It very well fits the definition of "arbitrary".
360 still isn't arbitrary. It's based on counting all the digits of your fingers from ancient Mesopotamia
[deleted] · -2 points · Posted at 16:23:13 on January 9, 2016 · (Permalink)
It's like you didn't even read what I wrote. Here, I'll paste the definition again:
based on or determined by individual preference or convenience rather than by necessity or the intrinsic nature of something
Is 360° based on necessity (will the world end if we choose 12345° instead?) or on the intrinsic nature of the circle? No. Was it based on the convenience of being able to count on your fingers and divide it into many pieces? Yes. I can't make this any clearer...
You're stuck on semantics. Move past it, to understanding. "individual" is the word you need to focus on. Like it's neither individual nor arbitrary that we all have the same number of fingers.
So will the world end? No, but it's not convenience but consistency. Not individually, but as a civilization
Anger leads to the dark side
[deleted] · 1 points · Posted at 18:47:17 on January 9, 2016 · (Permalink)*
Please spare me this drivel. The question is about semantics since the beginnings. You can't start arguing about semantics (e.g. by saying "360 still isn't arbitrary") and then when things don't go your way, start speaking like a stoner for unknown reasons and backpedal.
So, you'd rather argue that radians is an intrinsic and nonarbitrary system and 360, is arbitrary based on convenience.
[deleted] · 1 points · Posted at 19:04:55 on January 9, 2016 · (Permalink)*
Yes, radians actually are intrinsically defined. For example d/dx sin(x) = cos(x) when x is in radians, but it's something like 180/pi cos(x) when x is in degrees. Similarly exp(x) = 1 + x + x2/2 + ... in radians, with degrees you need a factor pi/180 in front of every x. And so on.
But it's not my freaking point. That radians are intrinsically defined doesn't change the fact that 360° per turn is completely arbitrary.
I was suggesting that in contrast to radians, you're saying that degrees are arbitrary.
Because, that wasn't clear before and you're proof further obfuscates your point. So, i guess I have a better understanding of why you're so frustrated.
Is 360° based on necessity (will the world end if we choose 12345° instead?)
Then according to you, everything is arbitrary since no reason is ever good enough unless it literally saves the world from ending. Thus, the word loses all meaning.
Arbitrary is a judgement call. Something Reddit has problems with, as evidenced by your comment.
[deleted] · 2 points · Posted at 18:05:01 on January 9, 2016 · (Permalink)
Then according to you, everything is arbitrary since no reason is ever good enough unless it literally saves the world from ending. Thus, the word loses all meaning.
You've never heard of hyperbole before...? I'm done with this shit, believe what you want. I don't care if a few idiots are wrong on the internet.
Ok, when what reason is good enough in order to not be considered arbitrary by you? We've already established that "saving the world" will be a good enough reason, but "divides evenly by many numbers" is not.
So, according to you, we need something that's between those two levels of awesomeness. What if instead of saving the world it just saved a town? Would that be good enough?
How much utility does something have to have before it's not arbitrary?
[deleted] · 1 points · Posted at 18:12:16 on January 9, 2016 · (Permalink)
Are you illiterate? I wrote "I'm done with this shit, believe what you want." What could have made you think I had an interest in continuing this discussion? Look up the definition of necessity if you want, as I said I don't care.
Yeah, my bad. I should have expected that backing you into a corner with no way out except admitting that you're wrong would make you want to be "done" with the conversation.
[deleted] · 1 points · Posted at 07:55:32 on January 10, 2016 · (Permalink)*
Uh? You're sorely mistaken. "Necessity" is not a very complicated word. It means that we couldn't possibly have chosen anything other than 360 to divide the circle. This is obviously not the case, hence it wasn't necessary. Does this get through your skull? I didn't want to stoop to this level of explanation, hence why I didn't want to continue this discussion. If you're still confused, maybe ask another question on ELI5 about the meaning of "arbitrary".
Ok, so... first, something had to "save the world" in order to not be considered an arbitrary decision. Then it turns out "save the world" was hyperbole, and it merely has to be the case that the decision had "no other choice."
Again, I'm not really clear on how much utility a decision has to have before you'll consider it "not arbitrary." Also, your comment is uncivil (ctrl+F skull) and I considered reporting it. Finally, I'm not sure why you're messaging me about this a full day after you said you were done with the conversation.
[deleted] · 1 points · Posted at 14:10:02 on January 10, 2016 · (Permalink)
"A full day" = "11 hours". I was asleep, moron. Time zones, how do they work?!
It's only tiring because you're not answering my question.
How much utility must a choice have before you don't consider it an "arbitrary" choice?
If your answer is that the choice must be "necessary" then define necessary. Necessary to what? To saving the world? To my mood? If I make a choice that is necessary for my mood to be satisfied but it doesn't have any rational utility to a reasonable person, than isn't it arbitrary?
[deleted] · 1 points · Posted at 17:09:28 on January 10, 2016 · (Permalink)
a : of an inevitable nature : inescapable
b (1) : logically unavoidable (2) : that cannot be denied without contradiction
c : determined or produced by the previous condition of things
d : compulsory
This whole thing could have been avoided had you opened a dictionary.
Not really, because it's still a judgement call, isn't it?
Dividing a circle into 360 degrees is "necessary" if you want to have factors of 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360. This has practical applications because it makes certain kinds of math easier.
Likewise, destroying an asteroid is "necessary" if you want to save the world from an astroid.
But if you don't care about that stuff, then both of those decisions could be said to be "arbitrary."
So again, how much utility is needed, and who defines it?
atte- · 4 points · Posted at 12:07:03 on January 9, 2016 · (Permalink)
Probably just because it goes hand-in-hand with base 2, base 4 (never used), base 8 and so on. It only really makes a difference in computer science where binary (base 2) is used a lot.
[deleted] · 1 points · Posted at 13:04:22 on January 9, 2016 · (Permalink)
When working with computers base 16 would be called Hexadecimal. In Hexadecimal you can use the values 0 - F to represent each "hexit." This makes the hexit F equal the base 10 number of fifteen. What makes hexadecimal so handy for computer science is the fact that it can be converted straight into binary without a lot of overhead arithmetic. Say you have a single byte of data that's represented in binary as 1010 0101. Each group of four bits is a nibble. We know that the 1010 nibble is ten in decimal, and we know that ten is represented as A in hexadecimal. The 0101 nibble is five in decimal and in hexadecimal. Knowing both of these things we can then convert 1010 0101 into the hexadecimal value of A5. We can indicate that this is a hexadecimal value by writing 0xA5. What makes hexadecimal great is the fact that we can use it to represent a large amount of binary information in a human readable form that won't melt your eyes.
atte- · 1 points · Posted at 13:56:38 on January 9, 2016 · (Permalink)
You meant to reply to thenextbus and not me I assume?
risot · 1 points · Posted at 03:39:20 on January 10, 2016 · (Permalink)
Heres a question, if your using base 16 and you put a 0 after a 1 so like 10, would that be considered 16 or 10? If it is considered 10 could this be why we use base 10? As in its closest to base 1.0 in that way.
atte- · 1 points · Posted at 09:46:10 on January 10, 2016 · (Permalink)
10 in base 16 would be 16 in base 10. I think the most likely reason that we use base 10 is that we have 10 fingers.
In computer science, to count in base 16 we start using letters after 9.
Left is base 10, right is base 16 (hexadecimal)
0 - 0
1 - 1
2 - 2
3 - 3
4 - 4
5 - 5
6 - 6
7 - 7
8 - 8
9 - 9
10 - A
11 - B
12 - C
13 - D
14 - E
15 - F
16 - 10
17 - 11
risot · 1 points · Posted at 20:35:08 on January 10, 2016 · (Permalink)
I am still trying to understand this. So in a base 16 system, if you divide 1 in half do you get .5 or something different?
atte- · 1 points · Posted at 20:40:55 on January 10, 2016 · (Permalink)
Hexadecimal is very rarely used with anything other than integers, but you'd get .8.
w2qw · 2 points · Posted at 12:17:04 on January 9, 2016 · (Permalink)
It's nice for programming because computers generally store things in binary and binary and any base 2x system are easily convertible.
(0b for binary, 0x for hexidecimal) e.g.:
0b10011001 = 0x99 versus 153
0b1001.1001 = 0x9.9 versus 9.5625
You can count to 1024 easily if you used binary and 10 fingers, and more if you wanted to make things more complicated, which is possible by using more than just an on/off position (and increasing the base of your number system) or by using more body parts (and having more than 10 digits to use).
[deleted] · 2 points · Posted at 12:39:33 on January 9, 2016 · (Permalink)*
You can count to 1024 easily if you used binary and 10 fingers
Eh. I don't know about easily. It's not exactly an intuitive system usable by pre-literate people to count their cattle or whatever.
According to that logic, base 12 is better than base 10.
And that's why you see 12 pop up a lot too. 12 inches in a foot, for example. It's easy to measure halves, quarters, thirds, and sixths of a foot. If a foot were 10 inches, the only straightforward divisions are halves and fifths.
Also, the reason it's called a second is that a minute is the "first part" of an hour--the first division by 60--while a second is the second division.
There are a lot of interesting reasons listed in these comments... One that is mentioned a lot is because it is divisible by a lot of different factors. But what is missing is why it used to be important for a scale to be divisible by a lot of factors.
Back in the day, to make instrumentation, one had to score the increments by hand. Try this. On a sheet of paper, try marking one edge with exactly 100 marks. You can get the "50" and "25" marks easy enough by dividing in half then in half again. After that, you have to start dividing by five, which is more difficult to do accurately. Now try with 360 marks. Half and half again is 180 then 90. Half again gives you 45. A third of this gives you 15 and a third again gives you 5. Thirds gives you 240, 120. Half these gives you 60, 30, 15, thirds again gives you five before you have to start dividing by five. 5/360 is almost 1/100th of a circumference (.01389 of a circumference). To get similar resolution using base 10 and dividing by only 2s and 3s, you'd need a scale to 1600, with the smallest increment being 25.
So using 360, you can get to a resolution of nearly 1/100th of a circle just by dividing by 2s and 3s and you have easy access to 90 (1/4 circumference), 45 (1/8 circumference), 120 (1/3 circumference), 60 (1/6 circumference) and 30 (1/12 circumference), 15 (1/24 circumference) and 5 (1/72 circumference). Whereas with 100 units, you can get only to quarter circles before you have to figure out how to divide a line into five parts.
This is extremely convenient. In drafting, for instance, you can draw any 15 degree increment just using 30/60/90 and 45/45/90 triangles in combination. And in math/engineering, 30, 45, 90 have convenient degrees to radian conversions.
Originally it was though that a year was about 360 days, not so much the concept of the earth going around the sun but observing other planets in the sky and the stars. Stars would move from one position in the sky to another and then back again which took about 360ish days. From there a cycle or a circle had 360 degrees.
360 was settled on because it was just so damn divisible. Look at all the factors. 1,2,3,4,5,6,8,9,10,12,15,18,20,24,30,36,40,45,60,72,90,120,180,360.
Now compare that to a number like 100. 1, 2, 4, 5, 10, 20, 25, 50, 100.
Of course today with much more accurate measurements we know a year is closer to 365.25 days.
lucasvb · 320 points · Posted at 12:05:55 on January 9, 2016 · (Permalink)*
As far as I know, this is not entirely correct. Ancient civilizations had pretty accurate astronomy and most knew the year had 365 days and not 360. That's a slightly over 1% error and easy to detect with even crude instruments. Any reasonably large sundial will be accurate enough for checking this.
Last I read about it, Babylonians used a base 60 numeral system, and 360 = 6x60 seemed like a good division system for angles. It was efficient since 60 and 360 have a lot of divisors, and it was also coincidentally close to the number of days, so 1 degree was approximately 1 day.
This eventually carried over for the measurement of time, which is why we have a base 60 hour-minute-second system.
The ancient Mayan Haab calendar is 360 + 5 days: 13 months of 20 days each, followed by 5 "bad luck" days that were left unnamed. So yes, they had a very good grasp of astronomy and definitely knew that a solar year was more than 360 days.
This is more fascinating, how the hell could an ancient civilization figure out a year was 365 days? By looking at stars? But devices to record the accurate position of the stars did not exist?
In contrast to the Tzolkin calendar, which had 260 days and was used by the priests, the Haab calendar was developed by Mayan farmers and was thus significantly more practical. Farmers needed to know how long a year was because they needed to know exactly when to harvest and when to plant.
Fun fact: the ancient Mayans had not two but three calendars! By combining the Tzolkin and Haab dates, you got a unique set of time coordinates for each day that would have been good for the next 52 years. But what if you wanted to make a note of stuff that happened in the last generation, more than 52 years ago? For that, you would use the Long Count calendar. Most ancient Mayan dates would use all three calendars: the Long Count for historical purposes, and the Tzolkin + Haab for everyday purposes.
Likely the sun would have been their guide. In the northern latitudes, it's fairly straightforward to count the days between the solstices. There will be one day when the sunrise and sunset occur at their furthest point north on the horizon, and that event is observable without any tools.
Maybe I spend too much time indoors but if I didn't have maps and globes I can't imagine how I would know what is "the furthest point north". North star, sure, but I know it was picked to be the north star because it pointed north. You needed to discover North first.
It's the only star that doesn't move. Every other star spins around it.
Hour after hour, everything else moves. But the North Star just stays in the same spot.
It would be very obvious to every primitive mind that this is the head honcho star. Not the most bright star, but clearly all other stars are worshipping this one. Or, at least, it is special and different from all others for some reason.
(Before the pedants arrive: yes, the North Star moves very slightly during the night; it's not exactly on the pole.
Before, the ultra-pedants arrive: yes, I know that because the earth wobbles like a top the "North Star" changes slowly over thousands of years and was actually a star called Thuban back in Ancient Egyptian times. Today it's Polaris. In a few thousand years it will be Vega. Fun fact: right now (give or take a few years) Polaris has moved as close to the pole as it will ever ever get, and Earth is wobbling away from it on a long slow voyage to eventually point at Vega instead.)
Thootom · 1 points · Posted at 18:57:00 on January 9, 2016 · (Permalink)
The sun rising in the east would have been what they used for orientation before they discovered the magnetic north. That's actually why Europe is "the west" and Asia is "the orient".
The sun is your guide. You pick a point to stand the watch it's rising and setting move north and south. That's how you define north south east and west. Make sense?
Well, you don't need to know anything about "north" to know that the sunrise slides along the horizon as the seasons change. Then at some point in the summer, it starts sliding back down the way it came until it's winter again.
Trust me, if you didn't have anything to do but watch the sky, you'd catch on pretty quick.
zzzKuma · 3 points · Posted at 17:07:31 on January 9, 2016 · (Permalink)
Day length. The summer and winter solstice are very noticeable and regular.
In addition to the solstice others have mentioned, they also used a thing called the Heliacal Rising of various important stars to determine the length of the year and determine important dates.
Here's how it works (using Sirius as my example star).
One day you wake up before sunrise and look for Sirius. You never see it. Same story the next day. And the next.
Then one day... BOOM! you see Sirius rise shortly before the sun comes up and washes it out. Alright! Today is Sirius Day, baby!
And every day after that, Sirius will rise even a bit more before the sun. So if you got clouded out for a day or two, you can still figure it out because you'll see it the next day.
Each "important" star (they used about 10 or so) indicates a particular important day of the year.
For example, the Heliacal Rising of Vindemiatrix meant "it's time to harvest the grapes" to the Ancient Greeks! (TMI on Vindemiatrix)
They made them. Basic metal and or wood working and a lot of free time and you too could figure it out. The pirate observations where probably a simple procession of the sunset past landmarks and the people started recording the procession as accurately as they could. If you use larger objects as instruments then your accuracy can be increased too. It would be really easy to move a make shift sextant one minute of it was 100 meters across
wokcity · 74 points · Posted at 12:39:16 on January 9, 2016 · (Permalink)
60x60=3600
lucasvb · 12 points · Posted at 13:45:34 on January 9, 2016 · (Permalink)
If you assume 100 units, then you get 16.666666666....
That's certainly not an impossible number to work with, but it certainly makes doing calculations much much harder. For example if you wanted to multiply that by 4, or divide again by 6. Certainly not something most people could do in their head, and even with writing it down it would be challenging to people without training.
If, on the other hand, you assume 360 units. Then that problem is easy. Divide by 6 and your get 60. Divide again and you get 10. Multiply by 4 and you have 240. Calculations most people could easily do in their head, or simply memorize.
That's a real big plus when you don't have calculators or even easy access to writing.
lucasvb · 4 points · Posted at 13:47:32 on January 9, 2016 · (Permalink)
It just simplifies notation because common fractions have terminating decimal representations. For instance, 1/3 is super common but we have to write it as 0.333..., which sucks. In base 12, for instance, 1/3 = 0.4
Yeah, it's the whole reason for western measurement - ever base used is easily divisible with a minimum of numbers. 12 inches in a foot means that you can have half a foot (6"), a third of a foot (4"), a quarter of a foot (3"), and a sixth of a foot (2") as whole numbers that are easy to add together.
Base 16 is really great if you have to split things in half a lot (like in computer science), since you can go 8/4/2/1. But it's larger than base 12 for the same number of divisors.
Metric (base-10) is probably the worst possible base, and has no redeeming use qualities that I am aware of aside from people having 10 fingers making it convenient to count on your fingers, which is... not a great justification, and it sucks that we got stuck with such a crappy base system. 12 or 16 would have been way better.
There are many old units for weights and lenghts and so on which are based on 12. That makes it quite easy to calculate because 1/3 and 1/4 are nice numbers in base 12.
Some people argue that it works be easier if we used base 12, because it divides by 2, 3 and 4 nicely. The 3 times table would then go 4,8,10,14,18,20,24...
This is basically what I have heard as well. I read a pretty in depth article about it a few years back but can't seem to find the link. Is basically said that the Sumerians/Babylonians, who were quite adept at geometry, saw the angle that is now 60 degrees as being especially significant due to its radius being equal to its secant line, and being equally divisible within a whole circle. Because they had a number system that only went up to 60 unique characters, they divided that special angle into 60 pieces (degrees). Since there are six of this angle in a whole circle, a circle would therefor have 360 total degrees. The stuff about there being close to that many days in a year is mostly coincidence, as astronomy was good enough then for them to be more accurate with that.
Correct except I'm not sure they picked 360 because it's easily divisible. I think its more because circles weren't promenent back then. Instead they studied hexagons. 6 x 360
[deleted] · 1 points · Posted at 15:05:18 on January 9, 2016 · (Permalink)
Base 60!?
Have you seen anything incoded in base 64? I can't imagine trying to do math on my hands or in my head with something like that.
lucasvb · 2 points · Posted at 15:08:23 on January 9, 2016 · (Permalink)
It's not that difficult to work on larger bases, especially one with a lot of divisors. The bigger issue is probably memorizing the symbols, but you can get around that by making their value self-evident.
[deleted] · 1 points · Posted at 15:29:21 on January 9, 2016 · (Permalink)
What. That shouldn't count. 10 has a different symbol than 1. And there's nothing stopping them from going to 61 or more using this same pattern.
lucasvb · 2 points · Posted at 15:32:09 on January 9, 2016 · (Permalink)
Why shouldn't it count?
Would it really be different if we simply replaced the symbols 0-9 with a circle with that many dots inside?
Having the symbols be separate entities and distinct is all that is necessary for positional number systems to work.
[deleted] · 1 points · Posted at 15:48:24 on January 9, 2016 · (Permalink)
I mean using their system, there's no reason whatsoever to stop at 60. 1s get grouped up to 10. So 10s should be able to be grouped up to 100. Then a new symbol could be used for 100...
lucasvb · 4 points · Posted at 15:56:13 on January 9, 2016 · (Permalink)
Well, there are good reasons to stop at 60. Good number bases are a product of the smaller numbers, which occur often.
Interestingly, Babylonians got to base 60 by using their fingers, just like we got to base 10 by using them. They would tick off the phalanges (finger bones) on their right hand with their thumb - so the index would be 1-3, middle 4-6, ring 7-9, pinky 10-12. When they got to 12, they'd extend a finger on their left, like how we count. That got them to 60 with just two hands.
From what I understand, the origins are in the base 60 numeral system of the Babylonians.
But you are both sort of right about the year. The ancient Egyptians had a 360 day year, but they knew that an astronomical year was 365 days. So they had a 5-day drunken festival in between each calendar year to keep it all accurate.
I say we adopt this now. 12 30-day months and a yearly 5-day shitshow.
They knew it had 365 but they still altered their calendar to have 360. The same way we know the year is actually 365.25 days, but we just settle on 365 and tack on a day every four years.
The ancient people just tacked on 5 days when the ruling elite decided they needed to have an event to honor the gods.
That's what I read. My maths teacher basically said he made a guess about 360 being based on the days in the year, so I got home looked it up and Babylonians was the answer I found.
[deleted] · 2 points · Posted at 13:03:54 on January 9, 2016 · (Permalink)
Those people used electric lanterns, legends say.
[deleted] · 24 points · Posted at 10:24:46 on January 9, 2016 · (Permalink)*
That is a cool idea.
We could have developed "days" and "months" as degree units.
"This angle is 3 months long"
"All triangles angles summed up are 6 months long".
Perhaps even Way more visual, less abstract, for school pedagogy purposes.
Well longitude is broken up by minutes and correspond to time zones. 60 minutes is the width of each time zone and each minute, should, line up to a one minute offset of time from it's neighbors.
[deleted] · 8 points · Posted at 11:52:25 on January 9, 2016 · (Permalink)
Do you mean that every neighbourhood could enjoy a different time zone?
We could use this advancement to throw shit on our neighbours: "no wonder you don't agree with me, your life is literally retarded with respect to ours"
That is in fact how time was told before the advent of the railroad. Particularly via sundials. But also in that you would set your watch/clock based on whenever the sun was at its highest point / shadows were shortest, and make that noon.
[deleted] · 3 points · Posted at 13:35:14 on January 9, 2016 · (Permalink)
"You might think that, being back in the past, but here in the future we know you go and fuck yourself now."
[deleted] · 3 points · Posted at 17:25:21 on January 9, 2016 · (Permalink)
Maybe I don't understand you correctly, but longitude is broken up into degrees (180 West, 180 East, 360 in total). One degree has 60 (arc)minutes.
All these minutes have nothing to do with time zones. (a 'natural' timezone would have 360/24=15 degrees of longitude - but their exact distribution is often based on economical and political reasons).
If you've navigated a sailboat using Celestial Navigation (uncommon in these days of GPS) then you've heard of Right Ascension.
Right Ascension is basically the equivalent of longitude projected onto the sky (to locate guiding stars) -- but it is not measured in degrees! Instead it is in hours, minutes, seconds. So you wouldn't say "180.5 degrees," you'd instead say "12 hours, 2 minutes, 0 seconds."
There is a direct correlation between longitude and time. It is called arc time. I'm not really sure how to explain this, in this context so I'll just leave this.
Ah crap yeah I got it backwards. Oh well. I put the link up that would be better at explaining it than I could.
[deleted] · 2 points · Posted at 11:38:18 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 1 points · Posted at 11:48:50 on January 9, 2016 · (Permalink)
Well I respects your opinion. /s
bugi_ · 2 points · Posted at 16:02:49 on January 9, 2016 · (Permalink)
Interestingly in astronomy distances in the celestial sphere are measured in degrees divided into minutes and seconds. E.g. 2° 11' 40'' for 2 degrees 11 arcminutes and 40 arcseconds.
If today's a new moon, a week later it'd be a half-moon.
Another week, it'd be a full moon.
Yet another week, it'd be a half-moon again.
And again another week, and it's a fullnew moon again.
... Not exactly, but it's good enough back then, I guess?
First quarter is the half-moon (50% of the moon is lit) right after a new moon. Similarly, the third (or last) quarter is a half-moon right after a full moon.
Also, blue moons are due to the length of the month (28 to 31 days) not really being equal to the length of the moon's orbit around the earth (~29 days), right? It's still possible even if the moon's orbit is exactly 28 days. If January 1 is a full moon, January 28 29 would be a blue moon, the 2nd full moon of the month.
EDIT: Off-by-one error (January 28, instead of January 29)
Ya know what it was that confused me? You went from full moon to half moon to full moon again, and I knew that was off, my correction was just inaccurate.
HAHAHAHAH I love it. Is a prime base even possible? I'd think one major issue would be how slowly it would accelerate (LOTS of zeroes after numbers), right?
So in base 3 the numbers get "long" much sooner than with our regular base-10 counting, but in base-11 or base-13 the numbers would grow more slowly. (That is, fewer zeroes after big numbers.)
pretty sure seven days comes from seven heavenly bodies - seven god's names, i've used spanish here instead of latin figuring they would be more familiar to you : sun - sunday, domingo (Lord's day) : moon - monday, lunes : mars - tuesday (tieu=germanic war god, mars is roman war god), martes : mercury - wednesday (woden=odin) , miércoles : jupiter - thursday (thor), jueves (jove=jupiter) : venus - friday (frigg), viernes : saturn - saturday, sábado (sabbath)
If I remember my astro class correctly, we can see the length of a year even more simply than that by just looking at the time it takes for the sun to cycle from its highest to lowest points and back again. Though I'm not entirely sure that had any bearing on the use of 360 in circles...
You’re talking about a tropical year, Xeno_man is talking about a sidereal year. They differ in length by about twenty minutes (not five days; 360 divisions is a rough approximation for either).
Our calendar is a solar calendar. The winter solstice will forever fall on or near December 22, and so on. Thus the seasons are fixed.
However, if your calendar fixes the seasons, it cannot also fix the stars. They only drift by about 0.014°, or 50 seconds of arc per year, but give it a few centuries or millennia and it becomes significant.
Nope. The orbit of the Earth and the length of the day are not directly related. That we have a number of days close to a useful number for dividing circles is lucky, if OP's Babylonian astronomer story is true. (I am not a lawyer historian, but I don't think there's a definite answer. That story smacks of the "Oh, look at the adorably ignorant ancient people trying their best" narrative though.)
Good question, though! Wanna know something cool about orbits and math, though? The square of a planet's period, the time it takes to go around the Sun, divided by the cube of it's distance from the Sun gives you some ratio, right? Well, that ratio is the same for any planet orbiting the same star. (Or satellite orbiting anything, like the Moon and the ISS around Earth.) So, knowing the Martian year is about 1.88 times as long as an Earth year, how much farther away is Mars from the Sun?
[deleted] · 1 points · Posted at 13:56:24 on January 9, 2016 · (Permalink)
Nah, it was because the Babylonians counted in sets of 60.
Absolutely, I believe there must be a connection between 365 days in a year (which is an accident) and the resulting human imposition of 360 degrees in a circle.
It actually is related to a year. Take the number of feet around the equator and divide by the number of days in a year. Divide again by 1000 and you get 360.
I, for one, believe we should strap a giant rocket to China, pointing outward. We ignite the rocket at noon in China, causing the earth's orbit to slow down just enough to reduce our year to 360 days for the sake of convenience.
Nothing can go wrong with this plan.
dNitza · 0 points · Posted at 11:30:51 on January 9, 2016 · (Permalink)
So does that mean when we up and move to Mars, we will need to redefine a circle as having ~668 degrees?
Isn't Mars's period 668 Earth days? We'd have to redefine it as however many Martian days in a Martian year.
Actually looking it up, a Martian day is only about 1/2 an hour longer than an Earth day. Didn't expect them to be so close given the size differential.
vezance · 1 points · Posted at 13:28:33 on January 9, 2016 · (Permalink)
I don't think there is any causal relation or even correlation between the size of a planet and its rotational period. Size wouldn't matter.
I was basing this on a quick look at this table and didn't give it much thought. Gas giants are spinning hella fast, and the smaller planets slower than Earth. You're probably right that there's other factors involved, or else Venus wouldn't have a 243 day rotation.
vezance · 2 points · Posted at 13:51:32 on January 9, 2016 · (Permalink)
(I could be wrong) If I recall correctly, the rotational periods of all planets were decided at their formation, based on the conditions under which they were formed. Sometimes they gained/lost speed after being hit by asteroids. Additionally, they all lose speed over time (earth is also slowing down).
Edit: Not to take this too offtrack, but I know an expert on this - /u/Astromike23. Maybe if he sees this he might add more insight.
You could divide a circle into as many regular parts as you wish. One of the reasons 360 is so convenient is because it's the smallest number divisible by all single digit numbers except 7.
blbd · 5 points · Posted at 19:01:11 on January 9, 2016 · (Permalink)
The 360 was arbitrary but intentionally arbitrary. It was before they had calculators by hundreds of years. So the mathematicians and geometers picked a value evenly divisible by many commonly used smaller numbers such as 1 2 3 4 5 6 8 9 10 and 12.
It is relatively arbitrary, but one benefit of 360 over 100 is number of factors.
360: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180, 360
100: 1, 2, 4, 5, 10, 20, 25, 50, 100
Edit: To provide an example, what's 5/6 of a circle in degrees? Using the 100 degree method, it's 83.333... . Using the 360 degree method, it's 300 degrees, a much more friendly number to work with.
[deleted] · 8 points · Posted at 19:58:31 on January 9, 2016 · (Permalink)
Every metric is essentially arbitrary. But they are chosen by people because of their usefulness.
There are other measurements for circles, and are used depending on applications, but the reason the 360° metric is most common is because with it a circle is easily divided into parts that are whole numbers. A circle measured in degrees is easily divided by 2,3,4,5,6,8,9,10... And you don't get any fractions. Its a large number because it enables you to further divide those portions equally as well and still have whole number measurements.
It is this same reason that a day is divided into 24 hours of 60 minutes and 60 seconds. A day can be easily divided into 86400 seconds, 1440 minutes, and all of those numbers can be easily divided by 2,3,4,5,6,8,9,10,12,15,16,18,20... And you'd still get at the very least a whole number of seconds in each.
(They're not all arbitrary - radians is essentially inescapable once you do calculus on sin cos and tan - only when you use radians does y=sinx differentiate to y=cosx etc.)
[deleted] · 1 points · Posted at 22:25:01 on January 9, 2016 · (Permalink)
Well radians are based on measurements of a circle (1 rad is the angle formed in a segment of a circle where the circumference equals the radius, 1:1ratio of r and c gives you 1 rad) so of course they are going to demonstrate a naturally occurring component of one. But the metric itself is still arbitrary (for example, if D was used instead of r to form the measurement, the full circumference would be equal to pi, not 2pi). Like I said the metrics are created because they are useful.
Edit: TL;DR: Your way would break calculus, which is why we need to use radians, as I perhaps didn't emphasise properly, sorry.
Detail:
Your response suggests I may not have emphasised the calculus bit strongly enough, as you seem to have missed that bit. If you define it that way, then when you differentiate y = sin x, you will get 2 cos x, not cos x, and a whole lot of very nice maths will suddenly get needlessly much more complicated.
All measurements of angle are arbitrary, yes, until you get to calculus. You have to use radians unless you want calculus to work differently.
This paragraph edited to expand : If you don't use radians, you either have to redefine sin to not be the y coordinate
on the circle x2 + y2 = 1 of a point at that angle, or give up on differentiating sin x to get cos x. Radians are the only way you can measure angles where sin x differentiates to cos x.
Radians aren't there because they're nice, they're inescapably there because they work.
[deleted] · 8 points · Posted at 07:56:19 on January 9, 2016 · (Permalink)
Babylonians liked 60 for calculations. Probably because it can be divided evenly by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30. So many practical, fractional portions aren't too difficult. And as a result, we still use 60 secs, 60 minutes, 60x6 degrees for angles which allows even more subdivisions.
Clare47 · 1 points · Posted at 10:58:23 on January 10, 2016 · (Permalink)
My understanding is that the babylonians used 60 because of the counting system they used with their fingers, instead of counting with each finger (for a total of 10) they counted the space between each knuckle on one hand (not including thumb, for a total of 12) and kept track of the number of twelves with the other hand. Five twelves are 60. This is how I understand we got the 12's and 60s in current measurements (seconds, minutes, hours, feet, inches, degrees etc). That may not be 100% accurate as it's just my understanding, the counting system is real for sure though.
No, it's not arbitrary against most comments here. It was wisley chosen and is a special number just like 60 or 24 on the clock. The idea is that 360 has 24 divisiors which end up in integer number without decimals. The much larger number 1000 for example has only 12 integer divisiors and would be unpractial.
I can't recall the mathematical name for this special numbers. As far as I remember it was the Mayas who used this reasoning.
You've hit on one of my pet peeves. This is probably my biggest complaint of how trigonomentry is taught (at least how it was taught to me many years ago).
They should not even bother with degrees until they first go over radians. Radians is essentially measuring the circle as a unit of PI.
It is SOOOO much easier to deal with radians in trig than degrees.
360 has a lot to do with the Babylonians and the fact that there were roughly 360ish days in a year. So, not exactly arbitrary, but historical.
sdb2754 · 3 points · Posted at 21:05:51 on January 9, 2016 · (Permalink)
Yes. Degrees are arbitrary. Radians are not, though. Radians relate the arc length to the angle. c = r*theta.
I guess this is the typical problem in measurements. A system in place is difficult to change. Radians make more sense, but most non-tech people will continue to use degrees.
Sure. You can divide a circle any way you want. We use 360 degrees for a few reasons. Partially it is because it is a multiple of 12. 12 is a nice number because it is evenly divisible by so many numbers. You can divide it by 2,3,4, and 6. 10, on the other hand, can only be divided by 5 and 2. So, twice as many potentials for an even fraction. But since 360 is also a multiple of 10 you get to divide it by 5 as well.
360 evenly divides by so many numbers it just makes the math easier.
Bu the same can be said for any combination of 5 and 12. You get a lot of nice and easy to work with fractions with 60. So why 360?
A big reason is the orbit of the Earth. We have 365 days a year. We've known this for centuries. If we say a circle is 360 degrees then working out how much of an arc the Earth moves in it's orbit for a given period of time is dirt simple.
In the time before CNC machines, industry used machines called automatic screw machines. Instead of computer control, the machine was controlled by cams and wheels that made the machine do certain functions during the cycle. The wheels were divided in to 100 segments, which makes the math necessary to "program" the machine much easier. So instead of degrees, we would talk in terms of "huns."
The ancient Babylonians used a base-60 system in which each digit was subdivided into 6s and 10s. In this case 360 = 6 x 60. This convention may be based on 6 equilateral triangles joining in a hexagon around a point.
It is, of course, otherwise just a matter of convention. The most pure unit is radians (a full circle is 2*PI), which maps the degrees to length of the arc of a unit circle.
Arbitrary but rational. The use of 360 for circles/time/geography goes back to Mesopotamia. Base 60, called sexagesimal, is convenient if you prefer to avoid fractions, because 60 is evenly divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60. Three hundred sixty is a multiple of 60 and further divisible by 8, 9, 16, 18, etc. It's also close to the number of days in the year, especially if you're willing to count the year as 360 days plus ~5 intercalary days.
[deleted] · 2 points · Posted at 17:07:47 on January 9, 2016 · (Permalink)
Sort of on Topic: It also came from the days in one year, but 365 is not divisible easy, while 360 can be divided into many factors.
Sure. The reason why it's divided into 360 is because the Sumerians (I think) had a base six math system and that's where it's derived from. That's also why there's 60 minutes in an hour.
[deleted] · 2 points · Posted at 00:50:09 on January 10, 2016 · (Permalink)
On another level this question makes us question the relationship between human symbols and the world they are supposed to represent. In the deepest sense aren't all symbols are essentially empty and it is only by custom that a symbol represents some "thing" in the object world.
360 isn't arbitrary. There are 365 days in a year, so 1 degree is approximately the distance the sun moves along the ecliptic in one day. However, 360 is divisible by more numbers and is easier to divide by 4 in particular. The history of sexagesimal counting is very interesting https://en.wikipedia.org/wiki/Sexagesimal.
Seems pretty arbitrary to me. Is every fourth circle a leap circle?
Edit: well I guess that is the length of the four seasons, so I guess it's not all that arbitrary...
[deleted] · 2 points · Posted at 02:01:10 on January 10, 2016 · (Permalink)
There is no 'natural property' of a circle in relation to a quantity of 360. So it is arbitrary, although a little research (startpage.com it) will give you insight into the reasoning behind '360'.
A circle does have a natural property which is not arbitrary, the ratio between its circumference and its 'width' (expressible as either its radius, or its diameter).
As I can recall, using 360 allows for many multiples, since it is base 12, instead of base 10.
geking · 2 points · Posted at 03:45:58 on January 10, 2016 · (Permalink)
This is from the Babylonians. Same reason why we have 60 seconds per minute and 60 minutes per hour. They used a base 60 math system. (We use a base 10 and computers use base 2).
in ancient times, astronomers looked to the sky and saw that different stars moved each night. they noticed that it took 360 days to do one full rotation about the sky (give them a break, they had ancient tech and we're off by 5 days). for this reason, the stars moved in a "circle" by 360 units, or days. these units are now called degrees.
Ancient astronomers knew full well that it took 365 days for the stars to move through their circle. They were keen observers of the night sky, and they weren't stupid.
It's named after the skateboard move, where the board goes a full circle during a jump, which is called a three-sixty. When the sumerans and babylonians discovered the circle, they remembered that awesome full circle skateboard trick and thus decided to use "three sixty" -> 3, 60 -> 3 hundred + 60 -> 360 degrees in a circle as an hommage to ancient skateboard skills.
I don't mind it. I just want them to stop with the banners that let me know I can change it back.
[deleted] · 1 points · Posted at 23:26:15 on January 9, 2016 · (Permalink)
I don't like it. It seems like it use to load more videos per page, now I have to reload the pages more often.
Loki-L · 2 points · Posted at 08:00:44 on January 9, 2016 · (Permalink)
Yes, it is arbitrary. This is why there are alternate measurements of angles in use like for example radians (which involves pi) and even obscure decimal ones like gradians which subdivide a right angle into 100 parts instead of 90 as degrees do.
The 360° thing is still the most common one for most general cases and it goes back all the way to the same people who decided that the day should have 24 hours and stuff like.
Both degrees and hours by the way share the same subdivision; minutes and seconds. A degree is divided into 60 arc-minutes and those are divided into 60 arc-seconds each.
If you want you can always simply use something like 'turns' instead of a degree. 360° are one full turn. A right angle is a quater turn or 0.25 turns and a single degree is 1/360 of a turn or 0.00277.. turns.
If you want to divide the circle into 100 parts call them centiturns and use that.
It doesn't really change anything how you measure it.
But it's not consistent. Pi is based on the diameter, so your base arc length should also be the diameter. With radians, the base arc length is the length of the radius, so the circle constant should also be based on the radius. Tau radians in a circle. Pi "dradians" in a circle. That's consistent.
You're right of course, I just prefer pi because I usually use it, there is no good reason to use pi over tau but I don't think it makes much of a difference.
There are 360 degrees in a full turn because it can be easily divided by 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360, which is quite useful. 100 can be divided by 2, 4, 5, 10, 20, 25, 50 and 100 which is less useful.
gladeye · 2 points · Posted at 19:47:45 on January 9, 2016 · (Permalink)
I'm in the midst of teaching my fourth grade students about angles and we discussed this exact question. I showed them that 100 degrees won't get you an accurate enough measurement, while 1,000 degrees would be near impossible to read. I always thought 360 was a nice compromise between the two, and is especially useful because 360 is such a highly divisible number.
It is arbitrary in that it was the preferred system by a generation long gone, they chose it over other systems that could have been about as useful.
It was not selected out of a hat, but because it most closely reflected how they viewed the cosmos to be constructed, which in turn likely had something to do with their mythology and social constructs.
They could have used a different setup just as accurately. Measurements and demarcations are all arbitrary based on a society's needs, familiar things, and mythologies. The reasons they selected the current one with were not arbitrary. The set they chose, was.
fiwer · -1 points · Posted at 18:18:30 on January 9, 2016 · (Permalink)
"Vortex Math" is a bunch of nonsense, as is the rest of your post.
risot · 1 points · Posted at 22:50:30 on January 9, 2016 · (Permalink)
So i take it you don't actually understand it.
fiwer · 1 points · Posted at 02:44:10 on January 10, 2016 · (Permalink)
Yeah, just like all the people who call timecube nonsense. Clearly they just aren't capable of understanding 4 corner simultaneous days rotation of the Earth!
[deleted] · 1 points · Posted at 03:04:16 on January 10, 2016 · (Permalink)
You are educated stupid.
risot · 1 points · Posted at 03:29:19 on January 10, 2016 · (Permalink)
It's clearly something you haven't even attempted to understand which first of all shows how ignorant you are. Its relatively simple math and you have no idea it even exists because your too ignorant to spend 5 minutes learning about it. Why not try coming back when you've learned anything at all about it and then explain to me how it is wrong rather than talking about something thats entirely unrelated to try to make a "point" about something you know nothing about.
fiwer · 1 points · Posted at 03:33:23 on January 10, 2016 · (Permalink)
Have you attempted to understand that you are educated stupid and the Earth has 4 corner simultaneous days?
risot · 1 points · Posted at 03:50:41 on January 10, 2016 · (Permalink)
Clearly you will have to continue resorting to comparing this to unrelated things in order to call it "wrong" because A, you refuse to research it at all, and B, even if you did you still couldn't explain how its wrong. So bring on the next completely unrelated comment! You sound like an idiot.
fiwer · 1 points · Posted at 04:26:02 on January 10, 2016 · (Permalink)
Do you spend a lot of time researching things that are immediately and obviously complete nonsense? Do you legitimately believe that the ramblings of schizophrenics have value?
risot · 1 points · Posted at 06:00:51 on January 10, 2016 · (Permalink)*
By "immediately" you mean you didn't research this at all, and it is obvious because it doesn't even involve listening to a person, it is entirely math equations. But of course you wouldn't know that because your too dumb to research anything about it.
Its amazing how forcefully you are refusing to research it at all whatsoever because your afraid i might be right. You can't even say a single word about it. If you want to try debating it thats fine but until your actually capable of discussing the first thing about it, shut the fuck up.
fiwer · 1 points · Posted at 15:12:13 on January 10, 2016 · (Permalink)
I did research it, it's complete nonsense. When you have a degree in a math heavy field like I do, you get exposed to a ton of cranks who believe they've unlocked some magical secret to the universe and learn to recognize them pretty quickly.
risot · 1 points · Posted at 18:18:18 on January 10, 2016 · (Permalink)
Yet for some reason you are incapable of explaining how its wrong. Again, you cannot even say a single word about it.
fiwer · 1 points · Posted at 18:35:42 on January 10, 2016 · (Permalink)
There's nothing to even explain. Again for comparison with Timecube, if I ask you to prove that the Earth doesn't have 4 simultaneous corner days within a single rotation, what can you say to that? There's no way to disprove lunatic ramblings because they aren't based in reality or logic.
You're either a very uneducated conspiracy nut with no math background or a legitimately crazy person if you believe in Vortex Math so it's unlikely any amount of evidence will convince you otherwise, but here's a link debunking it anyway. http://goodmath.scientopia.org/2012/06/03/numeric-pareidolia-and-vortex-math/
risot · 1 points · Posted at 20:16:55 on January 10, 2016 · (Permalink)
Interesting how that debunks everything except the one claim that i actually made, in fact it admits that doubling or dividing any single digit number will result in a never-ending, repeating pattern. The only claim that i made is that these patterns exist for the same reason that there is a never-ending, repeating pattern that comes out of doubling or dividing 360, both of these patterns work in the same exact way. This much is undeniable, even from this debunkers perspective.
On another note, when Einstien was asked what its like to be a genius, he responded "i wouldn't know, ask Tesla". Are you claiming that Tesla's use of 3, 6, and 9 was all just bs even though some of his inventions are still classified? I'm pretty sure im going to trust what two of the greatest minds to ever exist have said over a random redditor lol
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[deleted] · 3 points · Posted at 13:50:08 on January 9, 2016 · (Permalink)
All measurement systems are arbitrary. At a certain point it just becomes which makes more sense to use or which is easier. Iirc 360 degree model harkens back to Ancient Babylon who used base 60. And was modeled because of our year being 365 days.
gonzo41 · 1 points · Posted at 13:28:25 on January 9, 2016 · (Permalink)
if you divide a circle by 6400, 1 degree is roughly 1 meter at 1000 meters. Its handy if you need to shoot someone...
Circle stuff.. i thought the 360 was from being able to divide a circle into triangles with effectively flat sides that would make measuring the diameter possible.
A little late to the party but i've seen some answers that were close, this is the full picture;
Roughly 4500 years ago, the Babylonian time calendar was based upon a civilization wide understanding of base-60. Everything involving the time-table we adapted from them, Using 6 for Babylonians is like the difference between 10 and 1 for us, It isn't hard to factor up to 360 by their standards.
This all came from early predictions of a 'year' or then 'cycle', by tracking the sun and movement of the stars as well as seasonal occurrences, it took 90 days for each 'season' to change.
From this principle as we later adapted in our own modern culture now a primitive circle (read: Cycle) was mathematically defined as 360, because of the divisions it allowed and a little bit of heritage to the first ever humans to define a circle (inadvertently).
kyubez · 1 points · Posted at 13:57:26 on January 9, 2016 · (Permalink)
someone please answer this, if it is arbitrary, why 360? why not 100? i get that 360 has more factors, but wouldnt 100 have been more convenient considering how we use the metric system?
There's no such thing as a unit of measurement that isn't arbitrary. It's usually a matter of convention and familiarity which ones we use, though sometimes ones that have more practicality gain ascendancy.
umbama · 1 points · Posted at 14:22:08 on January 9, 2016 · (Permalink)
You can geometrically construct the 360 subdivisions using the equivalent of a compass and pencil - string and stick in sand for example. It's very easy. That would be a consideration.
To be honest, the only reason we still use 360 degrees is because it divides cleanly by 2, 3, 4, 5, 6, 8, 9, 10, and 12. Which makes it easy to teach basic geometry.
Historically the usage is tied to marine navigation. But that is more interesting and complicated.
yes it's arbitrary, the radian is unitless, if you wanted to make your own measurement system for angles, you could. That being said, 360 is a nice number to work with.
Fatburg · 1 points · Posted at 15:06:11 on January 9, 2016 · (Permalink)
You can divide a circle by any arbitrary method you want. For example:
I always figured that our Time, (seconds, minutes, hours), Day length, and radius principles, always fitting neatly into a base 12 design had something to do with us ending up with it...
Wee2mo · 1 points · Posted at 15:59:58 on January 9, 2016 · (Permalink)
360 was popular because it has a lot of counting numbers that can divide it into counting numbers.
[deleted] · 1 points · Posted at 16:28:42 on January 9, 2016 · (Permalink)
Everything is arbitrary. Even the integers that we think of as ubiquitous and certain are completely meaningless realistically, and have virtually 0 probability of existing in any true capacity.
360 degrees is a convenient choice for a number of reasons. First, the number 360 is divisible by a bunch of small integers: 2,3,4,5,6,8,9,10, and even 12 (like a clock). This is good because you can have even quadrants or thirds or sixths or eighths (like NW, SW, SE, etc) if you like. Our minds sort of stop really easily visualizing prime parts around 7 and onward-you can draw a square pretty easily but try drawing a heptagon! Second, 360 divisions is fine enough to allow for decent accuracy without too much mathematics. If you start in one place and head 10 miles in one degree direction, and you were off by maybe a half a degree, you are still at most only a few hundred feet from your desired destination.
Of course it's arbitrary. Any number system or system of measurements or standards is arbitrary. It's the same way you can use either kilograms or pounds to measure weight. The standard can be whatever you want it to be as long as a group of of people agree on it. I believe the 360 degrees in a circle is based loosely on the 365 days in a year somehow? http://math.stackexchange.com/questions/340467/why-is-a-full-circle-360-degrees
Yeah completely arbitary. Degrees are also made up of "arcminutes" and "arcseconds". There is 60 arcminutes in one degree, and 60 arc seconds in one arcminute, or:
1 revolution = 360° = 21,600' = 1,296,000''
1° = 60'
1' = 60''
Thats also where the unit 'parsec' came from, where a parsec is the distance from the earth when 1 AU subtends an angle of one arcsecond.
Yes it is completely arbitrary. Other commonly used divisions are 2*pi and 400.
400 was used in navigation back when the definition of a kilometer was a 1/40000th of earths circumference. The distance from the pole to the equator was defined as 10000 km.
2*pi is the choice used when doing math, since it's much simpler to use when we're looking for exact solutions and not estimations.
It's arbitrary, probably due to the astronomist that they divide the circle in more or less parts that has a year, a year has 365 days and a circle 360 parts..
It isn't completely arbitrary as some have said. 360 is a Highly Composite Number. While there is some arbitrary factor, there is a very specific reason why that number was 360 and not 359 or 361. You can see some other useful numbers on that list, such as 12 (inches in a foot), 24 (hours in a day), 60 (seconds, minutes).
Afaik it goes back to babylonian astrology, they divided the year into 360 days, 5 days of the year they just ignored. 360 is very divisible. and it is 6x60, the babylonians had a 60 based number system.
polot38 · 1 points · Posted at 18:58:09 on January 9, 2016 · (Permalink)*
Basically, yes. 360 degrees is arbitrary. It might have some historical significance or something, but that is, in mathematical terms, arbitrary. It has a lot of factors, but that is also arbitrary as there are a lot of numbers with a lot of factors. The other main system of radians, however, is a little less arbitrary, although that mostly has to do with differentiating trig functions.
Seeing all these comments that say it is completely arbitrary, and only a few mention Pi at all. After calculating the value of Pi, that calculation can be used to create a perfect circle (by mashing it into an equation and shit, proofs, technical terms, blah blah). Anyways, I assume that since a perfect circle can be created by using the value of Pi, 360 was also somehow derived from that.
But as you can see, I am very far from sure about this, so don't quote me.
jrm2007 · 1 points · Posted at 21:40:03 on January 9, 2016 · (Permalink)*
It is interesting to note that after the French Revolution where many changes were attempted they tried for decimal time (100 seconds per minute and 100 minutes per hour, 10 hour days I think) and it would not surprise me if they considered your idea also.
As a previous commenter said, 360 works with pi. Trigonometry frequently uses pi (a set value at 3.14159265... that cannot change) along with angle values to work out other angles, sides, areas, circumferences, radii, diameters etc. If the 360 degrees was changed, the proportion of each angle would not, but its value would, and so the algebra would no longer work correctly. Pi could be changed accordingly, however if this happened it would no longer be usable without angles, e.g. pi x (radius squared) = area of a circle would be incorrect.
360 was also chosen because it is very close to the number of days in a year. (The earth moves about 1 degree around the sun per day) So it's a mix of that and being able to divide it evenly by many number
It's like using feet or meters to measure distance. Alternatives to degrees include radians (of which there are 2*pi in a circle). The underlying angle is independent of how it's represented
[deleted] · 1 points · Posted at 22:39:14 on January 9, 2016 · (Permalink)
Arbitrary? Yes, as all conventions are. In science rads are used (1 turn = 2Pi = 6.28..) since it has really neat mathematical properties that makes you say "it just works".
360 was chosen because it divides by a lot of useful numbers (2, 3, 4, 5, 6, 9, 10, 12, 15, 20 and so forth).
Also, the Babylonians divided an hour in 60 minutes made of 60 seconds. Also there it's close to the number of days there is in a year, so that for a given hour in the day, everything shifts about 1 degree in the sky.
The military, most commonly artillery divisions use miliradian which is a circle divided by 6283 (6400 usually). It's for more accurate targeting over large distances. 1 degree is a bad miss, one that often kills friendlies over a few miles.
[deleted] · 1 points · Posted at 23:39:23 on January 9, 2016 · (Permalink)*
It's not arbitrary. People a long ass time ago figured out that time can be measured very easily using the numbers 0,1,2,3,4,5, and 6. Time is determined by the rotation of the earth, and the earth is round therefor time is measured using a circle. There are close to 360 days in a year, so they just used that instead and tried to figure out a way to explain the other 6.25 days. Notice how there are 60 seconds in a minute and 60 minutes in an hour. That wasn't an accident. The math just seemed to work out. People keep saying that ancient civilizations thought the year was 360 days long, and I am pretty sure that isn't right. I don't think people thought the year was 360 days. I think 360 made the math workout easier, so they removed 6.25 days from the calendar year and made up a reason to omit them. Many ancient civilizations were pretty clever and could make impressive calculations, so I can't fathom them not being able to count the days using orbital patterns and then do a simple calculation to determine the number of days in a year.
Also, I might not be 100% right about this, but I seem to remember some archeoastronomy theorizing that if you hold your arm out your arm towards the sky at night and use your thumb as a reference point, that there are typically 360 thumb width distances when measuring the year looking at the constellations. Somebody who knows more, please chime in here, I can't remember who it was that said that.
Also, you could measure a circle using 100 degrees, but you are going to fuck up our entire math system to where people had to use decimal numbers or fractions to do what we consider basic calculations.
Sort of on topic: Can someone explain to me if we correct the calendar every 128 years to make up for the fact that the year is not 365.25. It is 365.24219 days long. That means we lose a day every 128 years. I never have seen this brought up?
To your last point, the last year of every century (1900) is not a leap year. This applies to centuries that are not multiples of 400 (2000) which are leap years unless they are also multiples of 4000 (4000).
[deleted] · 1 points · Posted at 00:14:54 on January 10, 2016 · (Permalink)
Oh cool. When did they start doing that? It had to have been pretty recent, last 1000 years.
Pope Gregory in March 1582. By that time, the calendar year was 10 days off the seasonal year. ( The real concern was not Christmas, but Easter, which had to occur near the vernal equinox and according to the lunar cycle, but that's another story.) They made two corrections. The first was that they just dropped ten days. The day after October 5, 1582 became October 15, 1582. (Some countries adopted this change later, in some cases centuries later.) This restored the equinox to its rightful place. The second change was to reform the calendar to prevent slippage in the future; and we use that same calendar system today, called the Gregorian.
[deleted] · 4 points · Posted at 00:23:04 on January 10, 2016 · (Permalink)
Dammit... I'm annoyed that everyone else here already explained this. basically 360 is an amazing number and you can divide it by A LOT of different numbers
If I'm not misinformed, pretty sure it dates back to base 12 being used for time. Minutes, hours, half days, inches, degrees, etc all come from an ancient culture that counted things by the 12s or 16 or 60 or something like that. Hopefully someone who knows it off the top of their head can elaborate.
I heard they chose 360 because people used to think there w ere 360 days in a year. To answer your question, the number of degrees is entirely arbitrary.
They chose 360 because that's how many unique combinations of letters there are in the word circle. Not really why, 360 is just convenient for math.
ilmman · 1 points · Posted at 01:51:56 on January 10, 2016 · (Permalink)
Isn't the circle shape amazing? It's like the most interesting shape every. It's universal and the ratio is always going to be the same. In most technology we use circular motion for things like dysons vaccums and all. I think the secret to the universe lies in the power of the circle.
In the Danish military some units use nygrader (new degrees) which is 400 degrees to a circle. Was told by my friend who was a platoon leader in a mortar division.
I actually just taught this to my 10th graders the other day! Circles have 360° because the ancient mathematicians (I forgot who exactly) noticed that the stars & constellations would move ever so slightly every night, and after 1 year they would be back where they started. So even though it would be a little over 364 days, 360 is a better divisor.
Yes it's totally arbitrary, and we also use another form of measuring circles. Radians. Radians are technically more accurate, and their system has a good reason for using the measurements it does, but degrees work well enough for any practical application. And degrees are a lot easier for most people to understand. After all, to use radians you have to have some understanding of trig, and algebra. For degrees you don't need any of that.
tokodan · 2 points · Posted at 17:19:55 on January 9, 2016 · (Permalink)
I don't understand what you mean with the accuracy of the angular units. As far as I know, 360 degree is EXACTLY a whole circle, as is 2 pi.
[deleted] · 2 points · Posted at 18:18:04 on January 9, 2016 · (Permalink)
You're exactly right, they're both easily converted to each other. This is like saying Celsius is better than kelvins, makes no sense they're the same measure just a different nominal value
Breaking down a degree into "1.5 degrees" or "2.7" is somewhat more difficult because they are not designed on base-10 and you have to convert base-10 into degrees which are base-60.
This is why your GPS does not offer you one neat 'location' option, but rather offers you at least three. You can have DDMMSS, or DD.XXX, or one of a few other formats, most of which are approximations (very accurate approximations, but approximations none the less).
tokodan · 1 points · Posted at 22:57:12 on January 9, 2016 · (Permalink)
But if longitude and latitude lines were defined in radians (and GPS devices therefore used radians), they would display a fraction of pi, which converted to decimal would give an approximation (I mean if you have 7/22 pi North, that would be interpreted as 0.31818N).
Come to think of it, degrees are probably more useful for digital devices as well, since it's probably (don't quote me on this, it's a guess) easier to convert base-10 to binary.
I believe the 360 degrees had something to do with the early approximations for the number of days in a year... 365 days is what we know now, but 360 degrees isn't that far off
[deleted] · 1 points · Posted at 21:58:24 on January 9, 2016 · (Permalink)
No, 360 degrees is not arbitrary. Yes, you can use other divisions. 360 degrees is harmonic with Pi.
" In 1936, a tablet was excavated some 200 miles from Babylon. The mentioned tablet, whose translation
was partially published only in 1950, is devoted to various geometrical
figures, and states that the ratio of the perimeter of a regular hexagon
to the circumference of the circumscribed circle equals a number which in
modern notation is given by 57/60 + 36/(602) (the Babylonians used the
sexagesimal system, i.e., their base was 60 rather than 10).
The Babylonians knew, of course, that the perimeter of a hexagon is
exactly equal to six times the radius of the circumscribed circle, in fact
that was evidently the reason why they chose to divide the circle into 360
degrees."
Why is it still used commonly? I really don't know. If you get into any math above algebra everything is just in radians because it isn't totally arbitrary like degrees and is extremely useful. Next time you here someone call out the US on using inches, ask them whether they measure angles in degrees or radians and proceed to hack away at their double standards.
No the selection of 360 is not arbitrary like mentioned by most comments here but very wisley chosen by the Mayas in the same way like the numbers 24, 12 and 60 on the clock.
360 is the smallest number with 24integer divisiors which end up without decimals. For example the much larger number 1000 has only 12 integer divisiors which makes it unpractial.
However using 720 instead of 360 would have had even more divisiors but was likely thought to be to large for most angles used.
Using newdegree where a full circle is 400newdegree sounds great in the beginning until u have to deal with decimals where with degree everything was smooth.
Edit: These numbers have a special name, but I don't remember and didn't find it on mobile inet.
Not arbitrary: think # of days in a year, now realize that number isn't perfect for dividing into lots of other numbers, so have your high priests/mathematicians (same difference) come up with some excuse why the Sun/God/thing took a rest for 5 days and you get 360. Egyptians did this and probably learned from the Babylonians and Sumerians
Anyway, 360 is nicely Divisible by 1,2,3,4,5,6,.... Yeah, they liked that number a lot. Circles were sacred (Sun, moon, orbits -Stonehenge type structures, yeah, ellipses came later) and so 360 had to be perfect.
[deleted] · -1 points · Posted at 10:03:25 on January 9, 2016 · (Permalink)
way back when, some ancient skygazer noticed "hey, that shadow is the same size and shape that it was about 360 (~1 year) ago," and showed the amazing phenomenon to his friends. over time, it came to be established that the year consisted of four seasons of about 90 days each.
science advanced and it was hypothesised that the seasons were the result of the sun orbiting the earth, so 360 degrees was a convenient analogue.
math and astronomy became more sophisticated, and eventually it was discovered that a year is actually 365 days. So those extra days became "holy" days (holidays).
This is the reason I studied liberal arts in college. None of my high school math teachers could tell me why there are 360 degrees. (I would have been just as happy if they had told me we would work in radians as we progressed.)
As it happens, I learned as part of a tangential discussion in a philosophy class that the 360 degree circle comes from the solar calendar. (Tangential! I love it when a pun comes together!)
Your high school maths teachers must have been awful, but couldn't you just have accepted that it's an arbitrary measurement? There are historical reasons for most arbitrary measurements like that, for example the mile is a thousand double steps and the cubit is the length between the elbow and the tip of the middle finger, it was simply convenient to do it that way.
It is completely arbitrary, just like how it's arbitrary that there are 60 minutes in an hour.
IIRC it is because the Assyrians pioneered early geometry and they thought that 360 was a "perfect" number because it was divisible by so many different things.
There are 360 degrees in a full turn because it can be easily divided by 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360, which is quite useful. 100 can be divided by 2, 4, 5, 10, 20, 25, 50 and 100 which is less useful.
Anrza · 0 points · Posted at 18:49:29 on January 9, 2016 · (Permalink)
It seems like everyone saying it's arbitrary, but is it really? I thought it was a rest of the Babylonian system which, in turn, was because they thought the year was 360 days long?
I have an assumption that I've not really researched... so we have a base 10 system for counting because in the early development of civilization ND language they would have used the simplest observations to construct the most complex ideas. So the fact that we have ten fingers basically lead to our base ten system.
In a similar way early thinkers needed to generate observational accuracy so that they could convey information to other people in writings and descriptions. On of the most complex observational muses would have been the night sky. This apparent sphere like dome offered patterns that could be observed, but how could these patterns be explored and how could this exportation be communicated to others. Well the main governing pattern to this night show is of course the year..... and finally my conclusion, the year is damn near 360 days thus it would make sense to split the sphere that makes up the heaven into 360 seperate sections. Why not 365? Well early observers may not have been as keen on observation as we are today so an estimation would have sufficed. And as a caveat 360 had a great deal of factors which lends itself well to mathematical manipulation (as others have mentioned in the thread)
A circle is 360 degrees because the ancient Greeks (iirc) thought a year was 360 days. In other words, it's a completely arbitrary number which survives simply because it would be too troublesome to change (and there's no particular reason to change it).
chad303 · 0 points · Posted at 02:02:21 on January 10, 2016 · (Permalink)
Arbitrary, yes, and very old. I believe the ancient Babylonians modeled the circumference of a circle with an inscribed hexagon. This gives Pi = 3 which is a pretty good estimate for bronze age math. This value for Pi actually shows up in the Bible. If you connect all the points where the inscribed hexagon intersects the circle, you get 6 triangles. The base number for the Babylonian number system is 60, and so, if you assign 60 degrees to every triangle, you get 360 degrees in a circle.
No the selection of 360 is not arbitrary like mentioned by most comments here but very wisley chosen by the Mayas in the same way like the numbers 24, 12 and 60 on the clock.
360 is the smallest number with 24integer divisiors which end up without decimals. For example the much larger number 1000 has only 12 integer divisiors which makes it unpractial.
However using 720 instead of 360 would have had even more divisiors but was likely thought to be to large for most angles used.
Using newdegree where a full circle is 400newdegree sounds great in the beginning until u have to deal with decimals where with degree everything was smooth.
Edit: These numbers have a special name, but I don't remember and didn't find it on mobile inet.
No the selection of 360 is not arbitrary like mentioned by most comments here but very wisley chosen by the Mayas in the same way like the numbers 24, 12 and 60 on the clock.
360 is the smallest number with 24integer divisiors which end up without decimals. For example the much larger number 1000 has only 12 integer divisiors which makes it unpractial.
However using 720 instead of 360 would have had even more divisiors but was likely thought to be to large for most angles used.
Using newdegree where a full circle is 400newdegree sounds great in the beginning until u have to deal with decimals where with degree everything was smooth.
Edit: These numbers have a special name, but I don't remember and didn't find it on mobile inet.
[deleted] · -3 points · Posted at 19:08:39 on January 9, 2016 · (Permalink)
"is there a reason it's 360 instead of any other number?"
response: "degrees minutes and seconds yo!"
His job merely adopts the number that OP questions. Please explain the importance of 1,296,000 parts of a circle? Is this a magic number? Does this answer OP's question? I literally have no clue where Mr. Land Surveyor was going with this.
Let me ELI5: Unless he's going to connect some sort of dot between what he does and WHY it is that way then it doesn't address OP's question at all.
No. Just...no. The fact that a year is close to 360 days is a coincidence, no other planet has the same number of days per year, or length of day, or anything else really.
Mathematics is entirely arbitrary, just like any other conceptual thought. You could choose to create a system of mathematics and measures that is unlike our mathematics, is self-consistent, and cannot be integrated into normal maths and measures.
Our numbering system is likely base 10 because of fingers, no?
Likewise they probably went with 360 for degrees based on the divisibility factor. I dont believe it's because a year is approx 360 days. If anything, less of a factor.
eqleriq · -4 points · Posted at 17:10:56 on January 9, 2016 · (Permalink)
a circle divided by 100 is 3.6°
to all those saying it is arbitrary: it is not. it has ties to early astronomical estimates
Pi is the ratio between the radius and diameter of a circle. Is isn't arbitrary, it's the same for every single circle.
1/360th is entirely arbitrary.
But yes, I'm the retarded one.
Glad we agree.
eqleriq · 1 points · Posted at 17:25:36 on January 12, 2016 · (Permalink)*
Guess what else is the same for every single circle: they're 360 degrees.
It's based on a rough estimate of the number of days it takes the earth to circle the sun, which was accepted as usable due to it being the lowest number with the most whole number multiple pairs. This was considered divine serendipity, but I guess you lack basic geometric historical knowledge.
Rough estimates and the will of the gods != Arbitrary
I answered the question in the original post:
Is it arbitrary? No.
Could we divide a circle by 100? yes, 3.6°.
What is 3.6°? 1/100th of a circle.
What is 360°, 1 circle.
It's like asking if the word "troll" is arbitrary. Then you point out some sort of historic definition of it, but in the end some asshole trolled someone else and out came the meat scraping sound "troll." Perhaps tens of thousands of years ago that sound was "ehfhhggg" but there you go. Is it arbitrary? No, because in 1300 ancient germany someone fell on a banana peel and landed under a bridge, and shouted "trulle." He broke his back, couldn't move and was now the "trulle" under the bridge.
Circles are, by definition, 360°.
Feel free to change it to 273.321136° based on the number of days a year your feelings aren't hurt on the internet
Rule 1, please. We know the Internet can be a rough place, but ELI5 has rules.
BTW, quick bit of editing of the last sentence there...
[deleted] · -1 points · Posted at 11:15:26 on January 9, 2016 · (Permalink)
Graphic artists learn that there are many ways to divide a given measure into equal parts. For example, rather than using inches, quarters, eights and sixteenths, etc. it is easier to divide the line using picas, agates, points, millimeters, centimeters, degrees, or decimal inch measurements. Any measurement system that divides the A and B points (no matter what the distance apart) accurately into the number units you desire. So I assume 360 degrees was chosen in order to make it accurate enough to point in as many different directions as reasonable that people can easily grasp.
The circle was divided into 360 parts for purposes of astronomy. Stars and planets were observed to move nightly so the circle was divided by the days of the year. Yes. there are 365 days in a year. But then they would have problems of division. A "correction" factor was likely applied..
ers-in · -9 points · Posted at 14:19:11 on January 9, 2016 · (Permalink)
no it's not!, because a circle have 4 x 90° degree vertical angles in it so it must be 360°. Now the question is: 90° is that arbitrary ?
bugi_ · 3 points · Posted at 15:57:59 on January 9, 2016 · (Permalink)
skipweasel · 3760 points · Posted at 07:55:21 on January 9, 2016 · (Permalink)*
Yes, and there have been other divisions.
Some engineers use grads, which divide a right angle into 100, and maths often uses radians, of which there are 2Pi in a circle.
EDIT: Many people have rightly pointed out that suggesting radians are arbitrary is wrong. Yes - you're right - it's part of fundamentals of the universe.
PartizanParticleCook · 5466 points · Posted at 08:16:57 on January 9, 2016 · (Permalink)*
Radians visualised
Edit: Thank you for the Gold, my gilded cherry has been popped.
Doomur17 · 3948 points · Posted at 09:25:22 on January 9, 2016 · (Permalink)
Halfway through my 3rd year of engineering school, it just clicked.
lucasvb · 5926 points · Posted at 11:53:40 on January 9, 2016 · (Permalink)*
I'm the author of the GIF. It's comments like this that make doing these animations worth it. :')
Thanks!
EDIT: Check my Wikipedia gallery and my Tumblr for more of my math/physics GIFs. I'm also working on a YouTube channel where I'll post some accessible, but more technical, explanations of math and physics topics in a few months.
EDIT 2: Check this comment if you want to know about how I made these.
PinchieMcPinch · 742 points · Posted at 13:03:08 on January 9, 2016 · (Permalink)
Do you have any more? Honestly, an album of stuff like this would keep me occupied for... well, depends how long the album is... but multiple mind-blowings would be like a mathematical orgy, if you can provide them.
xueimel · 961 points · Posted at 13:20:30 on January 9, 2016 · (Permalink)
not sure if relevant to your interests, but there's this.
Yarrick40k · 412 points · Posted at 13:54:14 on January 9, 2016 · (Permalink)
I use to be a tour guide for NASA, this will be great to explain the orbit path of the ISS on a flat map
[deleted] · 1574 points · Posted at 13:55:58 on January 9, 2016 · (Permalink)
[removed]
[deleted] · 84 points · Posted at 14:36:07 on January 9, 2016 · (Permalink)*
[deleted]
heliotach712 · 63 points · Posted at 15:02:59 on January 9, 2016 · (Permalink)
and a chief goddess of the ancient Egyptians...whose contributions to world heritage like the pyramids, they have vowed to destroy.
BassoonHero · 7 points · Posted at 17:34:46 on January 9, 2016 · (Permalink)
Oh no! Where would they store their grain?
EsotericAlphanumeric · 2 points · Posted at 16:22:58 on January 9, 2016 · (Permalink)
Yep, that pissed me off, because it's a legit awesome name for a girl. Ishtar doesn't have the same ring, unfortunately.
Cypraea · 2 points · Posted at 19:31:53 on January 9, 2016 · (Permalink)
I knew an Isis in high school.
Not that the terrorists mind wrecking the lives of random women, mind you, but goddamn, I'd expect better from everybody who opposes them.
kamronb · 1 points · Posted at 19:44:49 on January 9, 2016 · (Permalink)
And a perfectly tame mini-van Toyota made...
ForYourSorrows · 1 points · Posted at 20:27:48 on January 9, 2016 · (Permalink)
There's a fertility clinic near me called ISIS something something, and the sign just had ISIS in huge letters with the something something in small print beneath it. Kinda unfortunate.
nater255 · 105 points · Posted at 14:52:20 on January 9, 2016 · (Permalink)
Don't forget Archer! The Islamic State ruined my Archer ISIS shirt forever :(
holydragonnall · 9 points · Posted at 16:57:43 on January 9, 2016 · (Permalink)
Ruined it? Or made it better?
[deleted] · 1 points · Posted at 22:51:25 on January 9, 2016 · (Permalink)
Both?
[deleted] · 2 points · Posted at 00:04:21 on January 10, 2016 · (Permalink)
Krieger?
Fatally_Flawed · 1 points · Posted at 21:44:18 on January 9, 2016 · (Permalink)
A recruitment agency called ISIS put me in a job about a year ago. It didn't work out. Fucking terrorists.
Throwawayfabric247 · 1 points · Posted at 03:49:32 on January 10, 2016 · (Permalink)
What happened to calling them daesh?
superfudge73 · 1 points · Posted at 16:41:15 on January 9, 2016 · (Permalink)
The ruined my daesh t shirt
[deleted] · 1 points · Posted at 20:43:59 on January 9, 2016 · (Permalink)
Wear it anyways. I would.
Cypraea · 7 points · Posted at 19:26:35 on January 9, 2016 · (Permalink)
I went to high school with a girl named Isis. There are actual people with that name, that this is fucking up. It's like hurricanes (I have an Aunt Katrina), but worse.
dgrant92- · 1 points · Posted at 02:05:22 on January 10, 2016 · (Permalink)
No shit.Pretty sure if I email my aunt Katrina..no problem..but send my love to Isis? screewweedddd!
brother-funk · 3 points · Posted at 23:10:25 on January 9, 2016 · (Permalink)
They call themselves Daesh. Don't believe the bullshit, media created name. They don't deserve it.
cruzberry · 1 points · Posted at 00:27:13 on January 10, 2016 · (Permalink)
No, that's what they don't want you to call them.
SeenSoFar · 1 points · Posted at 03:03:53 on January 10, 2016 · (Permalink)
Daesh is the derogatory name in Arabic for the Islamic state. Fuck daesh.
MTL_Bob · 2 points · Posted at 15:37:46 on January 9, 2016 · (Permalink)
Agreed
That's why I tell everyone that will listen not to call them Isis, call them "Daesh" it's what everyone on the ground fighting (Pashmerga etc) refers to them as and they hate it (it is apparently very derogatory)
[deleted] · 2 points · Posted at 15:49:17 on January 9, 2016 · (Permalink)
Daesh, it is. I wonder if we could make a reddit post popular enough to make the media take notice and start using that as the defacto, popular term.
MTL_Bob · 3 points · Posted at 16:02:25 on January 9, 2016 · (Permalink)
It's actually kind of odd.. From my experience, only English media is still using Isis.. Any Arabic outlet uses Daesh.. And French switched to it after the Charlie Hebdo attack last year.. Would definitely be nice to see the undeniably influential American media also make the switch..
I like to explain it like this: do we refer to Kim Jung Un as "Dear Supreme Leader" just because he's decided that's his title? Or do we call North Korea "the Democratic Peoples Korean Republic"? No.. Because neither is a representative name..
_illusion · 1 points · Posted at 15:46:04 on January 9, 2016 · (Permalink)
Don't forget the women that have the name!
[deleted] · 1 points · Posted at 15:49:40 on January 9, 2016 · (Permalink)
never forget the womens
e39dinan · 1 points · Posted at 16:42:34 on January 9, 2016 · (Permalink)*
At least they kept the dog in the intro. It wouldn't be the same show without seeing her partially exposed butthole when that tail clockworks to the extreme left.
flea1400 · 1 points · Posted at 17:08:16 on January 9, 2016 · (Permalink)
They didn't choose it. The media chose it and continues to choose to use it. The name of the actual organization of murderous jackasses is not in English and doesn't use the Roman alphabet.
Personally, I call them "ISIL" which is just as valid and doesn't defame "Isis."
[deleted] · 1 points · Posted at 17:55:56 on January 9, 2016 · (Permalink)
Is that why President Obama refers to them as ISIL?
walkinthecow · 1 points · Posted at 01:24:53 on January 10, 2016 · (Permalink)
Was it Samsung that launched an ISIS app, which I think was a precursor to their mobile wallet app. That timing was ridiculously unfortunate.
muntoo · 1 points · Posted at 02:03:48 on January 10, 2016 · (Permalink)
These guys screwed up the amazing band ISIS. They had to rename to Isis the band, even though they haven't recorded an album in nearly a decade.
Fuckin ISIS.
[deleted] · 802 points · Posted at 14:46:10 on January 9, 2016 · (Permalink)*
[deleted]
dpmcleod · 57 points · Posted at 15:01:22 on January 9, 2016 · (Permalink)
I could watch that animation for hours. I wish I had it when I was in school, maybe I wouldn't have flunked out. (I'm all seriousness a whack of math came flooding in when I saw this). Cheers
cavortingwebeasties · 7 points · Posted at 19:14:45 on January 9, 2016 · (Permalink)
I bet I could eat a hundred animations.
Fricktitious · 4 points · Posted at 15:12:58 on January 9, 2016 · (Permalink)
Maybe whacking to math was the problem.
Joetato · 4 points · Posted at 17:05:23 on January 9, 2016 · (Permalink)
I fapped to Pythagoras's theorem once. It was hot.
ihatetheterrorists · 1 points · Posted at 21:14:03 on January 9, 2016 · (Permalink)
Maybe watching animation for hours was the problem? : )
brygphilomena · 1 points · Posted at 23:06:34 on January 9, 2016 · (Permalink)
I learned calculus in high school. Math up to that point was easy. It all just kind of made sense. But calculus didn't click. So I lost interest and my grades suffered because I didn't try anymore. It wasn't until almost 10 years later helping my little brother with a finance or business management course that I saw a problem and my mind went "This is calculus!!!" I understand everything now.
Makes me want to get out my old calc textbook and learn it all over again.
It was related rates that got me, the examples were shit and didn't clearly explain the use of it.
meladon · 1 points · Posted at 15:22:59 on January 9, 2016 · (Permalink)
Math. Where will you be when it hits?
ph_neutral · 9 points · Posted at 20:44:43 on January 9, 2016 · (Permalink)
Do you have any more? Honestly an album full of reddit comments would keep me occupied for... well, depends how long the album is... but multiple mind-blowings would be like a reddit comment orgy, if you can provide them.
sinematicstudios · 1 points · Posted at 15:37:26 on January 9, 2016 · (Permalink)
I'm the author of the author of this reply. It's comments like this that make replying worth it. :')
Thanks
Alphyn_dp · 1 points · Posted at 16:09:31 on January 9, 2016 · (Permalink)
Do you have any more? Honestly, a page of comments like this would keep me occupied for... well, depends how long the page is... but multiple mind-blowings would be like a reddit orgy, if you can provide them.
NorwegianGodOfLove · 1 points · Posted at 17:17:06 on January 9, 2016 · (Permalink)
Do you have any more? Honestly, an album of comments like this would keep me occupied for... well, depends how long the album is... but multiple mind-chucklings would be like a literary orgy, if you can provide them.
[deleted] · 1 points · Posted at 18:51:27 on January 9, 2016 · (Permalink)
Damn this made me ROFLMFAO!
dragontail · 1 points · Posted at 19:09:21 on January 9, 2016 · (Permalink)
This guy gets it
DepressedByPornHabit · 1 points · Posted at 20:12:35 on January 9, 2016 · (Permalink)
Do you have any more replies? Honestly, an thread of replies like that would keep me occupied for... well, depends how long the replies are...
Chinook700 · 1 points · Posted at 20:48:18 on January 9, 2016 · (Permalink)
Me too thanks
Gitdagreen · 1 points · Posted at 21:50:00 on January 9, 2016 · (Permalink)
🌟X 11
SimbaOnSteroids · 1 points · Posted at 15:33:38 on January 9, 2016 · (Permalink)
0 to meta in above average time
[deleted] · 0 points · Posted at 16:04:46 on January 9, 2016 · (Permalink)
[deleted]
FILE_ID_DIZ · 15 points · Posted at 14:36:28 on January 9, 2016 · (Permalink)
It's an older meme, so I hope this works out...
Nuke 'em from orbit.
[deleted] · 13 points · Posted at 14:41:35 on January 9, 2016 · (Permalink)
Can't agree more, it's time to wipe out infidels already!
PurestFlame · 5 points · Posted at 15:52:03 on January 9, 2016 · (Permalink)
Well, this is awkward.
IAmA_Catgirl_AMA · 1 points · Posted at 14:34:54 on January 9, 2016 · (Permalink)
The NASA never spied on the German government.
donutsinreverse · 1 points · Posted at 15:36:38 on January 9, 2016 · (Permalink)
Dammit. There goes the solar system!
spankinhank · 1 points · Posted at 15:44:37 on January 9, 2016 · (Permalink)
We're gonna have to blow it up
onesonesones · 1 points · Posted at 15:45:24 on January 9, 2016 · (Permalink)
ONLY DONALD HAS THE BALLS TO NUKE SPACE
[deleted] · 1 points · Posted at 20:41:39 on January 9, 2016 · (Permalink)
Makespacegreatagain
[deleted] · 1 points · Posted at 16:01:31 on January 9, 2016 · (Permalink)
[deleted]
onesonesones · 1 points · Posted at 16:03:17 on January 9, 2016 · (Permalink)
ISIS HAS A SPACE STATION NOW? FACK ME
[deleted] · 1 points · Posted at 17:11:50 on January 9, 2016 · (Permalink)
Seems like the NSA's handling it.
GETitOFFmeNOW · 1 points · Posted at 18:14:15 on January 9, 2016 · (Permalink)
It's okay, Mallory is making a deal.
wellbuttermybiscuits · 1 points · Posted at 19:24:25 on January 9, 2016 · (Permalink)
What is an infidel ISIS astronaut's favorite key on the keyboard?
The ALLAHU SPACEBAR!!!
...I'll see myself out.
flowstoneknight · 1 points · Posted at 21:45:34 on January 9, 2016 · (Permalink)
ISIS stands for "Islamic State, IN SPACE!"
swohio · 9 points · Posted at 16:56:20 on January 9, 2016 · (Permalink)
I think the best way to describe it is be drawing a sine wave on a flat piece of paper, then rolling the paper into a cylinder. If you run your finger along the drawn sine wave, it now gives the motion of a circular orbit. This demonstrates how the 3D orbit results in a sine wave on a 2D map.
Video with this demonstration.
agentid36 · 3 points · Posted at 17:17:25 on January 9, 2016 · (Permalink)
Kerbal Space Program with the scansat mod would demonstrate this too - but in SPACE! @1:53
kroxigor01 · 2 points · Posted at 01:05:05 on January 10, 2016 · (Permalink)
One day I hope you can show them the skull of Ghazghkull Mag Uruk Thraka
[deleted] · 4 points · Posted at 15:01:41 on January 9, 2016 · (Permalink)
[deleted]
Keroro_Roadster · 5 points · Posted at 20:33:58 on January 9, 2016 · (Permalink)
He used to work there.
He still does, but he used to work there too.
Malakael · 2 points · Posted at 02:47:57 on January 10, 2016 · (Permalink)
I hear he doesn't have a girlfriend; just a girl who would be really angry to hear him say that.
MJZMan · 1 points · Posted at 14:35:23 on January 9, 2016 · (Permalink)
I was recently wondering about orbit paths. Funny how questions can be answered when you least expect it.
Lingawakad · 1 points · Posted at 21:35:10 on January 9, 2016 · (Permalink)
it's also good for demonstrating phase-shift keying, as i understand it
sewneo · 1 points · Posted at 21:49:30 on January 9, 2016 · (Permalink)
What good is it on a flat map?
Yarrick40k · 1 points · Posted at 22:33:38 on January 9, 2016 · (Permalink)
In the ISS mission control room there is a giant screen with a map of the earth and on it is the location and path of the station.
[deleted] · 1 points · Posted at 00:54:54 on January 10, 2016 · (Permalink)
Sine wave no?
jchodes · 1 points · Posted at 01:31:39 on January 10, 2016 · (Permalink)
Okay, honestly educational moment for me then... Does the ISS no circle the earth? (I really had no idea)
Smithy2997 · 1 points · Posted at 01:47:03 on January 10, 2016 · (Permalink)
Those were a pair of 2s that I'd never put together before.
NSA_Chatbot · -2 points · Posted at 16:38:40 on January 9, 2016 · (Permalink)
'sup?
Oh, NASA. Sorry.
southsko · 28 points · Posted at 13:59:26 on January 9, 2016 · (Permalink)
Electrician here. I'm going to share this with some apprentices. Thanks bud
themeatbridge · 1 points · Posted at 14:24:49 on January 9, 2016 · (Permalink)
I recently saw a three phase version of this, and it blew my mind.
gazzthompson · 2 points · Posted at 15:28:26 on January 9, 2016 · (Permalink)
Link?
themeatbridge · 1 points · Posted at 16:51:24 on January 9, 2016 · (Permalink)
It was part of an online training powerpoint. I don't have a copy, but it showed how the three phases peak to keep the current more consistent.
OscarPistachios · -14 points · Posted at 16:04:07 on January 9, 2016 · (Permalink)
3 phase explained on a trig circle
khajiitFTW · 23 points · Posted at 15:00:42 on January 9, 2016 · (Permalink)
Excellent example of a sine wave. Hopefully teachers start using these animations more often. I think it could be a big help.
Corte-Real · 6 points · Posted at 16:35:47 on January 9, 2016 · (Permalink)
Does not conform to the Common Core Math guidelines. Sorry!
oconnellc · 1 points · Posted at 00:55:35 on January 10, 2016 · (Permalink)
We should go back to using 'new math', which confused an entirely different group of adults who couldn't learn grade school math 40 years ago.
Corte-Real · 2 points · Posted at 01:38:14 on January 10, 2016 · (Permalink)
When I couldn't remember the name of common core I just googled "new math" and came across that. Jesus Christ that was fucked. My favourite part of the article was a quip from the Simpsons.
TheYadda · 1 points · Posted at 22:54:44 on January 9, 2016 · (Permalink)
And Common Core just got gutted by the new education bill Obama signed. It's moot.
AnneBancroftsGhost · 1 points · Posted at 15:55:15 on January 9, 2016 · (Permalink)
I feel like I need to write my trig instructor a thank you note now because she explained all of these concepts really well.
[deleted] · 1 points · Posted at 09:39:03 on February 1, 2016 · (Permalink)
It's actually a cosine.
RakijaH · 4 points · Posted at 12:38:56 on January 10, 2016 · (Permalink)
/u/lucasvb actually has their own version on tumblr.
[deleted] · 2 points · Posted at 15:06:16 on January 9, 2016 · (Permalink)
[removed]
gophercuresself · 6 points · Posted at 16:21:50 on January 9, 2016 · (Permalink)
This I understand, but would you mind explaining why a sine wave is a circle displayed over time?
optical_power · 2 points · Posted at 00:03:34 on January 10, 2016 · (Permalink)*
Say you move around a circle with it's centre at the origin, at constant speed. At any point you will be at be a certain height above above or below the 0 line (x axis). BY DEFINITION the sine of the angle to where you are on the circle is defined as the Opposite / Hypoteneuse. Since you are on a circle the hypotenuse is always the same distance - the radius (ie from the centre to the circumference), but the height is changing - or the opposite. Therefore it is possible you can say two are sort of equivalent. Ie. the height changes thew same sine of the angle the height is at.
So as you go along the circle you can plot the height at any time along another graph. If you plot the sin of the angle cast on the same graph it will be exactly the same.
Tldr; It comes from the definition of what sine is.
Hope that helps. I'm not a mathematician and I last did this stuff at uni in the 80s, but it has always helps me to visualise moving pictures. You guys have gifs and videos - we had to use our imaginations.
sorry on phone so speeling erras.
gophercuresself · 2 points · Posted at 00:30:01 on January 10, 2016 · (Permalink)
That, along with this which I had a bit of a read through earlier have definitely helped me get a better grasp. After everything your tldr is pretty much the why I was after, even though it ends up being somewhat cyclical (excuse the pun). Thanks very much for your help!
[deleted] · 3 points · Posted at 13:47:08 on January 9, 2016 · (Permalink)
[deleted]
Bananananana_Batman · 21 points · Posted at 14:00:26 on January 9, 2016 · (Permalink)
It's a sin wave.
[deleted] · 1 points · Posted at 16:04:01 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 1 points · Posted at 16:58:49 on January 9, 2016 · (Permalink)
Not sure much about electrical engineering, but I know there is a specific equation that transforms a sine wave into a square wave, or it at least converges to it. I'll try to find try later but I'm on mobile.
apcragg · 1 points · Posted at 00:43:41 on January 10, 2016 · (Permalink)
The Fourier series of a 50% duty cycle square wave is the sum over every odd harmonic diminished by a factor of 1/n where n is the harmonic number.
[deleted] · 1 points · Posted at 00:50:26 on January 10, 2016 · (Permalink)
Holy shit I think I just orgasmed?
trojanhawrs · 1 points · Posted at 17:20:20 on January 9, 2016 · (Permalink)
Smoothed DC is a line, not a square wave at all, youre thinking about digital as opposed to analog. Without any smoothing a half-wave rectification of AC would look like a sine wave without the bottom half, as you say the troughs are at the x axis. Full wave rectification is what you want though, and this just flips the bottom part of the wave up to its same position along the x axis, making the top part of the waves overlap
Edit : actually they dont overlap, theyll become troughs as you said on full rectification theres just no pause between the waves, heres a picture. https://www.google.co.uk/search?q=half+wave+and+full+wave+rectification&safe=off&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjszebrnp3KAhWI0RQKHRAvBJ0Q_AUIBygB&biw=1920&bih=969#imgrc=Ip9o3ORFEfO-9M%3A
Smoothed DC though is effectively just a line drawn across the peaks
occasionallyacid · 1 points · Posted at 14:48:38 on January 9, 2016 · (Permalink)
OH MY GOD, FINALLY.
Qazdthm · 1 points · Posted at 15:53:49 on January 9, 2016 · (Permalink)
For the record the circle on the left can be called a phase and is used to easily depict everything from AC current and voltage in different circuits to EM waves
aussydog · 1 points · Posted at 17:13:08 on January 9, 2016 · (Permalink)
Goramit! Where was this when I was learning about the unit circle in high school.
nLotus · 1 points · Posted at 18:06:46 on January 9, 2016 · (Permalink)
/r/mildlyinteresting
[deleted] · 1 points · Posted at 18:11:35 on January 9, 2016 · (Permalink)
Now do tangent.
bobberpi · 2 points · Posted at 20:39:00 on January 9, 2016 · (Permalink)
here you go
ForYourSorrows · 1 points · Posted at 20:26:42 on January 9, 2016 · (Permalink)
That looks awesome and I feel like it brings me to the verge of understanding some cool concept but... What is that?
[deleted] · 0 points · Posted at 13:39:59 on January 9, 2016 · (Permalink)
That made me laugh for some reason.
skyman724 · -1 points · Posted at 13:46:25 on January 9, 2016 · (Permalink)
Polar graphs...I remember that nightmare.
QuantumHoneybees · 187 points · Posted at 13:45:30 on January 9, 2016 · (Permalink)*
I have this bookmarked. It explains so many mathematical things like Pascal's Triangle, Parabolas, and Polar Coordinates
thethiefofsouls · 8 points · Posted at 15:10:47 on January 9, 2016 · (Permalink)
I think the jar gif is a gas, so you could say fluid but not liquid, iirc
joonazan · 20 points · Posted at 14:11:14 on January 9, 2016 · (Permalink)
I watched the Cylindrical coordinates gif and it made them look horribly hard. Isn't it easier to just say that you can write a point as radius and angle?
Apolik · 28 points · Posted at 15:18:42 on January 9, 2016 · (Permalink)
That's because the animation is about the transformation from cartesian to polar. Not about "just" polar coordinates.
ohSpite · 3 points · Posted at 14:40:50 on January 9, 2016 · (Permalink)
I've only just started covering them so I may be wrong but that's essentially whats being done, where the distance from the origin (pole) is defined as a function in terms of the angle created ACW with respect to the positive x axis (incident line)
[deleted] · 4 points · Posted at 15:19:28 on January 9, 2016 · (Permalink)
No, it's brilliant. Made it click for me. I'm really good with 3D and spacial reasoning and the gif makes it very clear what's happening, for me at least.
alleigh25 · 2 points · Posted at 21:09:21 on January 9, 2016 · (Permalink)
Conversely, I'm terrible at visualizing things, and that gif finally made it click what the "real" connection between Cartesian and polar coordinates is. I could do the math, but I was always at a loss for what they had to do with one another in a real-world sense.
Also, it looks cool.
turtlehoof · 1 points · Posted at 16:27:39 on January 9, 2016 · (Permalink)
From everything I remember about cylindrical coordinates, they are horribly hard. The maths isn't particularly complex or anything, but everyone in my class found them an absolute pain for some reason. It may well be that the subject is just taught badly.
psychoanalogy · 1 points · Posted at 02:12:05 on January 10, 2016 · (Permalink)
to be fair it's usually a very early or even first introduction to alternate coordinate systems, which can be a hard concept for people who have been cartesians for their whole academic career
kyleqead · 1 points · Posted at 21:02:08 on January 9, 2016 · (Permalink)
Radius and angle work fine for two dimensions, but thinking about it, that isn't enough to describe a location in 3 dimensions. You can use spherical coordinates which gives you a radius, and 2 angles, so you know how far it is from the origin, and its angle with respect to two of the coordinate axes, which is enough info to get its location. Cylindrical coordinates rely on a radius, height, and angle. Radius denotes how far the point is with respect to one coordinate plane, the angle describes its location in said plain, and then the height describes its position with respect to the third axis. I think polar is fine for two dimensions, but when you get to 3, I much prefer rectangular.
Enthused_Llama · 2 points · Posted at 14:33:42 on January 9, 2016 · (Permalink)
Yep cylindrical coordinates are still horrible.
God_Damnit_Nappa · 1 points · Posted at 18:18:29 on January 9, 2016 · (Permalink)
THAT'S WHAT THE DIRECTRIX AND FOCUS IS FOR?! Ever since algebra 2 I thought it was just some pointless bullshit designed to annoy sophomores.
[deleted] · 1 points · Posted at 00:56:15 on January 10, 2016 · (Permalink)
So in the 19th GIF, with the spring falling, does the bottom not fall because the tension is pulling it up at 9.8ms-2 ?
Plasma_000 · 69 points · Posted at 13:38:26 on January 9, 2016 · (Permalink)
Most of the maths related gifs on wikipedia are made by /u/lucasvb
ChuqTas · 73 points · Posted at 13:45:49 on January 9, 2016 · (Permalink)
Perhaps /u/PinchieMcPinch wants this?
https://en.wikipedia.org/wiki/User:LucasVB/Gallery
Eight_Rounds_Rapid · 8 points · Posted at 13:55:42 on January 9, 2016 · (Permalink)
I'll say thanks anyway!
Mrbasfish · 30 points · Posted at 13:59:37 on January 9, 2016 · (Permalink)
Theres a sub dedicated to them! /r/mathgifs
brianlouis · 1 points · Posted at 14:37:03 on January 9, 2016 · (Permalink)
Of course there is. This is most excellent. Thanks for sharing!
OliviaEversea · 1 points · Posted at 14:43:44 on January 9, 2016 · (Permalink)
Cheers. subscribed!
lucasvb · 50 points · Posted at 13:43:43 on January 9, 2016 · (Permalink)*
I've only published half of the stuff I ever did. Most didn't work as well as I hoped and were too "wild" to belong on Wikipedia. I don't know if I have the source of all of them anymore.
[deleted] · 18 points · Posted at 14:05:53 on January 9, 2016 · (Permalink)*
[deleted]
lucasvb · 34 points · Posted at 14:08:28 on January 9, 2016 · (Permalink)*
Once I'm back to my apartment where my old files are I'll see what I can find and post to my Tumblr. I wrote your username down to notify you.
You can also just subscribe to the RSS feed if you want to keep up with my updates.
IAmA_Catgirl_AMA · 9 points · Posted at 14:38:27 on January 9, 2016 · (Permalink)
RemindMe! 1 day Come back to see if gifs are there.
lucasvb · 3 points · Posted at 14:40:51 on January 9, 2016 · (Permalink)
Oh, forgot to mention, I'll be back at the end of January. Make the notification mid-February.
pkiff · 2 points · Posted at 16:52:26 on January 9, 2016 · (Permalink)
RemindMe! 35 Days come back to see some shit.
youlawnsgetoffmykids · 2 points · Posted at 01:02:49 on January 10, 2016 · (Permalink)
I've seen so many of your gifs while looking up things for my various math classes. Your gif of the gram-schmit process was incredibly helpful. Thanks so much man
IAmA_Catgirl_AMA · 1 points · Posted at 23:10:51 on January 9, 2016 · (Permalink)
RemindMe! 35 Days come back to see some
shitcool maths stuffMarmadukian · 1 points · Posted at 23:37:13 on January 9, 2016 · (Permalink)
RemindMe! 35 days "cool math gifs"
PinchieMcPinch · 1 points · Posted at 09:16:47 on January 10, 2016 · (Permalink)
RemindMe! 40 days mathgasmathon!
pkiff · 1 points · Posted at 16:55:23 on February 13, 2016 · (Permalink)
I came back...
Marmadukian · 1 points · Posted at 23:46:54 on February 13, 2016 · (Permalink)
Me too...
fuzzer37 · 2 points · Posted at 15:11:14 on January 9, 2016 · (Permalink)
Do you actually have cat ears?
IAmA_Catgirl_AMA · 1 points · Posted at 23:13:33 on January 9, 2016 · (Permalink)
Uh, obviously
fucky_fucky · 3 points · Posted at 15:00:24 on January 9, 2016 · (Permalink)
Can you add me to that list?
[deleted] · 2 points · Posted at 14:37:49 on January 9, 2016 · (Permalink)
you out slummin', yo?
soxfan91 · 2 points · Posted at 15:15:39 on January 9, 2016 · (Permalink)
Add me to that list—some of these are perfect to share with my students! You're fantastic :)
khajiitFTW · 2 points · Posted at 15:01:38 on January 9, 2016 · (Permalink)
Notify the world.
ajaxanon · 1 points · Posted at 15:37:22 on January 9, 2016 · (Permalink)
Add me!
AN_IMPERFECT_SQUARE · 1 points · Posted at 17:50:07 on January 9, 2016 · (Permalink)
RemindMe! 35 Days
Stompysaurus · 1 points · Posted at 18:26:12 on January 9, 2016 · (Permalink)
RemindMe! 40 days wild math gifs!
[deleted] · 1 points · Posted at 22:49:53 on January 9, 2016 · (Permalink)
RemindMe! 1 month
bieker · 2 points · Posted at 15:47:09 on January 9, 2016 · (Permalink)
Some of the coolest graphics of this type I've seen were on NASAs website and were about orbital mechanics. Showing things like how the velocity changes in elliptical orbits so that the area swept by a line connecting the satellite and the nearest focus is always the same for equal periods of time.
I've never been able to find them again. Have you ever done any like that?
lucasvb · 1 points · Posted at 15:50:05 on January 9, 2016 · (Permalink)
That's Kepler's 2nd Law. There's a few animations of this around, just search for it.
I've done an animation with Newton's proof of it, which is entirely geometric.
TehNoff · 1 points · Posted at 15:01:27 on January 9, 2016 · (Permalink)
The idea of wild math gifs excites me.
reallymobilelongname · 1 points · Posted at 19:27:07 on January 9, 2016 · (Permalink)
Dude, you should make your own reddit and cross post to oddlysatisfying and interesting as fuck for the sweet sweet karma
lucasvb · 2 points · Posted at 19:31:06 on January 9, 2016 · (Permalink)
Eh, too much effort. I'll let others reap the karma.
odoprasm · 5 points · Posted at 13:50:50 on January 9, 2016 · (Permalink)
LucasVB is apparently some kind of mathgif making savant. Check out his contributions to Wikipedia: https://en.wikipedia.org/wiki/User:LucasVB/Gallery
Mad props to LucasVB
jugalator · 2 points · Posted at 13:48:36 on January 9, 2016 · (Permalink)
Just keep scrolling through the replies... :)
http://math.stackexchange.com/questions/733754/visually-stunning-math-concepts-which-are-easy-to-explain
alomomola · 2 points · Posted at 15:26:26 on January 9, 2016 · (Permalink)
Just so you know, he edited his comment with links :)
marlow41 · 2 points · Posted at 18:13:32 on January 9, 2016 · (Permalink)
https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Gram-Schmidt_orthonormalization_process.gif
This is one of the best gifs of anything mathematical I've ever seen.
Ketherah · 1 points · Posted at 14:12:38 on January 9, 2016 · (Permalink)
/r/educationalgifs
RexFox · 1 points · Posted at 14:30:53 on January 9, 2016 · (Permalink)
r/MathGifs
GIGATeun · 1 points · Posted at 14:33:48 on January 9, 2016 · (Permalink)*
I made this, if you're interested in additive synthesis (creating other waveforms purely with sine waves)
Also, this
VanRayInd · 1 points · Posted at 14:35:13 on January 9, 2016 · (Permalink)
They would keep me occupied as long as I was high
mlmayo · 1 points · Posted at 14:36:27 on January 9, 2016 · (Permalink)
Do you care if they are videos or must they be GIFs? There are competitions for mathematics visualizations. For example, there's the Vizzies. One winner I really liked was about Mobius Transformations, of all things.
rummyCube · 1 points · Posted at 15:11:44 on January 9, 2016 · (Permalink)
another really good link for this (about Julia fractals, but goes pretty in depth) How to Fold a Julia Fractal
theartofbeingrude · 1 points · Posted at 15:15:27 on January 9, 2016 · (Permalink)
Bless you.
Grintor · 1 points · Posted at 15:17:57 on January 9, 2016 · (Permalink)
https://en.wikipedia.org/wiki/User:LucasVB/Gallery
mishper · 1 points · Posted at 15:23:05 on January 9, 2016 · (Permalink)
Yes, he's made lots more: http://1ucasvb.tumblr.com/archive
[deleted] · 1 points · Posted at 15:55:25 on January 9, 2016 · (Permalink)
/r/educationalgifs
Zhanchiz · 1 points · Posted at 18:07:38 on January 9, 2016 · (Permalink)
Here are some I found earlier.
Kowzorz · 1 points · Posted at 19:57:08 on January 9, 2016 · (Permalink)
/r/mathgifs
/r/educationalgifs
DidItForTheStory · 1 points · Posted at 19:58:21 on January 9, 2016 · (Permalink)
There needs to be a subreddit for this type of stuff
Obeeeee · 1 points · Posted at 21:24:30 on January 9, 2016 · (Permalink)
/r/iamverysmart
jargoon · 1 points · Posted at 02:14:16 on January 10, 2016 · (Permalink)
Prepare to have your mind exploded (best viewed on desktop but should work on mobile)
http://acko.net/blog/how-to-fold-a-julia-fractal/
fongaboo · 90 points · Posted at 13:13:06 on January 9, 2016 · (Permalink)
Looks like you made this one as well? Really helped me understand Fourier transforms.
lucasvb · 121 points · Posted at 13:18:40 on January 9, 2016 · (Permalink)
Yeah. That one was aiming at explaining time/frequency domains. Fourier transforms have been my nemesis. I never found a good way to illustrate them.
Most illustrations show only that they work ("here are some magical frequencies. Look what happens when we add these waves!"), not why/how they work. The transform is about extracting the "weight" of each frequency, after all.
I think I found a GREAT way to explain it which goes through linear algebra. But I'll need to make a video with narration and an interactive page. That'll be coming in the near future.
seaandtea · 21 points · Posted at 13:23:06 on January 9, 2016 · (Permalink)
This is, you are, awesome. Errr...How soon? Where can I find it when it's done?
lucasvb · 17 points · Posted at 16:24:58 on January 9, 2016 · (Permalink)
Subscribe to my YouTube channel where I'll post it in the future.
[deleted] · 2 points · Posted at 17:17:08 on January 9, 2016 · (Permalink)
Subscribed for the future.
[deleted] · 1 points · Posted at 02:22:25 on January 10, 2016 · (Permalink)
Somehow I think this will make my next few years at the uni easier
bugtank · 6 points · Posted at 13:52:14 on January 9, 2016 · (Permalink)
Probably his tumblr. The link is on the gif.
Monsterpiece42 · 2 points · Posted at 13:36:16 on January 9, 2016 · (Permalink)
I second this!
nfergi · 6 points · Posted at 14:06:46 on January 9, 2016 · (Permalink)
Dude, your gifs are awesome! I'm sending the radian one to one of my professors to use. Please keep up the amazing work.
lucasvb · 2 points · Posted at 14:11:12 on January 9, 2016 · (Permalink)
Thanks! I will. :)
jared_number_two · 3 points · Posted at 13:46:46 on January 9, 2016 · (Permalink)
How do I subscribe to your work?
lucasvb · 13 points · Posted at 14:05:44 on January 9, 2016 · (Permalink)
You could subscribe to my Tumblr's RSS feed.
Whenever I make anything new I'll post over there.
Azurphax · 2 points · Posted at 13:28:33 on January 9, 2016 · (Permalink)
Thanks for your gifing
door_of_doom · 2 points · Posted at 17:46:49 on January 9, 2016 · (Permalink)
For anyone who wants to learn more, I think that what really made them click for me was watching a web series on those Harmonic Analyzers that did these calculations manually. This series from the engineer guy (https://www.youtube.com/watch?v=NAsM30MAHLg) is absolutely fantastic.
meshugga · 2 points · Posted at 18:59:35 on January 9, 2016 · (Permalink)
15 years ago or so I wrote a wikipedia article. A small, puny one, about a book. And it was a TON of work.
Since then, guys that contribute to WP in any way are my heroes. But you specifically are simply put, the hero of heroes. You really go way beyond of what is expected of reference material and cross the line into actually educational, which is rare even for very expensive material, not to mention free.
Also, your way of mathing speaks to me. Thank you from the bottom of my heart. I have trouble expressing how awesome you are for contributing to WP in the way you are.
lucasvb · 1 points · Posted at 19:19:12 on January 9, 2016 · (Permalink)
Thank you for the kind words!
The way I see it, I'm not really contributing to Wikipedia. I'm contributing to everyone. Wikipedia just happens to be a good vehicle for that. :)
This is why I always release these animations in the public domain, and try to make them language-agnostic. I just want people to have them. All the people.
I do wish I could get proper credit when people repost them around, because hey, I put a lot of effort in these. But getting credit is insignificant compared to the value of thousands of people learning about math. That's why I do this.
Once again, thank you.
from_dust · 1 points · Posted at 14:24:00 on January 9, 2016 · (Permalink)
Do you have a subreddit or site where people can dig into this? I've always excelled at geometry because I think with the logic and visual/spatial relationships very well, but the formulaic approach killed me for algebra and calc etc. these are brilliant for me to understand all the "Greek" in math in a way that related to things I understand.
Thank you!!!
lucasvb · 2 points · Posted at 14:28:21 on January 9, 2016 · (Permalink)
Not yet. I have a few stuff in my Tumblr, but it's not super in-depth.
I've been working on a YouTube channel where I'll explain a lot of math and physics stuff with more depth, but still in an accessible way. The technical animations I make will be of great help here. I'm dropping the link now so you guys can subscribe and get the video later, once I start uploading.
Some of the YouTube videos will also have a blog post and maybe interactive applets associated with them, since I think a lot of these concepts will need that kind of interaction to really sink in. You'll know about it when these videos come out.
[deleted] · 2 points · Posted at 14:32:19 on January 9, 2016 · (Permalink)
INSTANT SUBSCRIPTION
Might be very interesting and helpful for me. Thank you for your work!
_Fallout_ · 1 points · Posted at 18:22:41 on January 9, 2016 · (Permalink)
As a physics major, I'd just like to say that your gifs are generally regarded as awesome and super useful
Dafuq_McKwak · 1 points · Posted at 23:10:25 on January 9, 2016 · (Permalink)
I'm looking forward to this, as your gif cleared up a lot of confusion I had in the beginning about FT. I've developed some neat intuitions about how the transform actually works, and I can see how it would be difficult to actually present something visual without making a mess.
Actually going this deep isn't required to pass my courses, but I feel like it pays off both in pure intuition and in being awe struck by how clever we humans actually are.
Your gifs have helped me develop this intuition, so I thank you and look forward to seing content on your youtube channel :-)
exponentialfuckup · 1 points · Posted at 13:30:20 on January 9, 2016 · (Permalink)
Anytime during these couple of weeks would be great, just in time for finals. :D
DrDucati · 8 points · Posted at 14:55:01 on January 9, 2016 · (Permalink)
Damn, I just can't seem to understand this one. Fourier transforms have been the death of me, conceptually.
door_of_doom · 9 points · Posted at 17:47:58 on January 9, 2016 · (Permalink)
Try watching this series on harmonic analyzers, the machines that were created to perform these calculations manually. I feel it really made them click for me: https://www.youtube.com/watch?v=NAsM30MAHLg
Azurphax · 1 points · Posted at 13:27:32 on January 9, 2016 · (Permalink)
Ohhhh that's a beaut
ezone2kil · 1 points · Posted at 13:40:17 on January 9, 2016 · (Permalink)
Fourier transform made me give up on being an electronics engineer =(
noisycat · 170 points · Posted at 13:12:57 on January 9, 2016 · (Permalink)
I always had trouble with geometry because I needed visualizations to learn and everyone's attitude when I was in school was "just plug the numbers into the formulas". So thank you for making this gif. (There weren't gifs when I was in school, haha) I finally get to have something geometry related click after 20+ years and it makes me happy. Thank you :)
lucasvb · 297 points · Posted at 13:21:07 on January 9, 2016 · (Permalink)
You're not the only one having issues, our system is broken. It's one of my long term goals in life to do whatever I can to fix math and physics education by making use of modern technology. Hopefully in a way that's public domain and easily translatable to other languages.
We could be doing so much more to teach these concepts with clarity. These animations are just a tiny contribution to the effort I can make right now.
Thanks for the kind words. :)
[deleted] · 44 points · Posted at 13:50:42 on January 9, 2016 · (Permalink)
I had an amazing geometry teacher who had a real passion for helping people understand geometry -- he drew almost that exact same thing on the board, and explained it the same way. He died a few years back, so this makes me smile... Thanks for making it.
lucasvb · 19 points · Posted at 14:06:16 on January 9, 2016 · (Permalink)
Aww, that's awesome. You're welcome.
summercampcounselor · 15 points · Posted at 14:41:08 on January 9, 2016 · (Permalink)
We need a set of YouTube tutorials that brilliantly explain things where the average teacher fails.
I asked a few teachers if they share reliable YouTube tutorials amongst themselves and they all said no. That should change.
YourBrainOnJazz · 11 points · Posted at 14:52:39 on January 9, 2016 · (Permalink)
Khan Academy is pretty darn good for instructional videos. Definitely not perfect, but if you get stuck on something then there's a huge forum of peoples questions and answers.
AnneBancroftsGhost · 2 points · Posted at 16:02:15 on January 9, 2016 · (Permalink)
According to my high school math teaching cousin, she would love it if her students even cared enough to cheat on their homework by using wolframalpha or sth. But the "bad" students are the ones giving zero effort. And the students doing poorly that want to do better? Her biggest recommendation to their parents is to make flash cards and memorize their times tables. That's how broken or system is.
user__3 · 1 points · Posted at 18:50:21 on January 9, 2016 · (Permalink)
I'll be going to junior college for the first time in a couple of weeks and I'm taking a math class; I really hope my teacher will actually care to explain the math instead of just telling the students to read the textbook and memorize formulas.
AnneBancroftsGhost · 1 points · Posted at 21:34:22 on January 9, 2016 · (Permalink)
I'm sure it depends on the school but I haven't had an instructor yet that wasn't super interested and passionate about their subject (I'm at a jc as well).
psychoanalogy · 1 points · Posted at 02:20:34 on January 10, 2016 · (Permalink)
You've got it wrong though;
especially in higher math, the textbook is your best friend.
You want to read the textbook and then question the fuck out of your instructor
edit: just wanted to add, don't let anyone spoon feed this shit to you. get hungry
[deleted] · 1 points · Posted at 15:20:42 on January 9, 2016 · (Permalink)
Khan Academy. Enough said.
Urban_bear · 18 points · Posted at 14:36:45 on January 9, 2016 · (Permalink)
Thank you for your work. I too lost interest in mathematics when a teacher failed to explain how and why something worked and told me just to memorize the formula. Visualizations and logical explanations will go a long way to fixing that type of issue.
akuthia · 2 points · Posted at 20:07:13 on January 9, 2016 · (Permalink)
Which is damn sad because at some point math becomes not about equations but about logic. I can't tell you where because despite having aptitude in math up through algebra 3/trig in high school when I tried to restart my life with mathematics I stumbled at calc 1
psychoanalogy · 1 points · Posted at 02:19:01 on January 10, 2016 · (Permalink)
The college-level calc series is largely an extension of the high-school algebra.
There are a million million sub-disciplines like logic, modern algebra, combinatorics, graph theory, topology, number theory, etc that are very different than what we're used to (and had ruined for us) in the public education system.
It's all about proving things based on prior assumptions with logical rules (maybe a generalization but eh)
Creative_Deficiency · 4 points · Posted at 15:13:38 on January 9, 2016 · (Permalink)
This turned a bit long and rambly.
Has our system always been broken? I don't mean a specific national education system, I mean the way math has always been taught. Was there some way in the past that math was taught better than now? One thing I especially liked about some math teachers I had was when they talked about the people that came up with the math. I had to google the name, but one that stood out was Galois, in my linear algebra class. He had done amazing things and died at an age where a lot of people are still considered children today.
How did he learn math? Are people like him flukes, and genius beyond my capability? I really feel like I'm too dumb for math. I don't lose sleep over it. The universal response to this when I tell people about my feeling, is that 'anyone can learn anything,' or 'I just needed to try harder.' I feel like that's a feel-good answer, and I don't believe it. Could I learn like Galois? Is it the system that failed me? Or did I just not try hard enough? Or can I just not be that smart in math?
Chii · 2 points · Posted at 19:16:36 on January 9, 2016 · (Permalink)
apropo: https://youtu.be/Cj4y0EUlU-Y?t=64
feynman explained in the vid that ways of thinking, for even something as simple as counting numbers, is actually vastly different between different people. So when somebody doesn't understand something, it's usually because their "internal" model is somehow incompatible with the way it's being explained to them, not that they are dumb. A genius might actually just be an accident where their internal model happens to be very well suited for a certain kind of explanation, and mode of thinking - leading them to be able to grok faster, and like compound interest, their knowledge "savings in the bank" just grows much faster than average. So to achieve the same, a person with an incompatible mental model might have to work twice, or three times as hard.
1337ndngrs · 1 points · Posted at 22:46:15 on January 9, 2016 · (Permalink)
I agree with this. I have a really good internal dialogue when it comes to grasping new concepts, but I've noticed others don't seem to click the same way. I've learned that the best way to teach is to ask questions of the students in the right way to guide them to the answer instead of just giving it to them. I tutored a friend in high school for about an hour the day before his final, and he said he learned more than he had the entire year. Schools are broken, plain and simple.
InfiniteBlink · 1 points · Posted at 00:04:33 on January 10, 2016 · (Permalink)
I love Feynman and his brilliant explanations. I like it when he gets flustered explaining stuff. I'm gonna binge on him again. Thanks for reminding me
1337ndngrs · 2 points · Posted at 22:42:07 on January 9, 2016 · (Permalink)
If you ever want some tutoring I'd gladly start a youtube/twitch channel to answer your questions! I feel like I'm a pretty good teacher and would love to make videos to help people understand math better!
lucasvb · 2 points · Posted at 17:38:58 on January 9, 2016 · (Permalink)
I think it's always been a bit obtuse. I've had the chance to pick two very old math books to check out, and the methods are pretty much the same. Hell, even some of the exercises were the same.
The general narrative of math texts is just backwards, in my opinion. So I think people who managed to thrive just have the proper upbringing and mental mindset, for whatever reasons, to understand it. Everyone struggles with something or the other. It's hard to tell what actually goes into the minds of the geniuses, and we don't really have a good idea of their background.
But making things clear and simple to understand is extremely hard, too. So there's quite a bit of inertia and regurgitation in the way of progress.
the_itsb · 3 points · Posted at 14:53:10 on January 9, 2016 · (Permalink)
Thank you so much for your dedication to helping fix things! Because of people like you, I know my daughter will have an easier time finding alternative resources to explain complicated concepts, and she'll have a better chance to understand and learn to love math instead of dreading and loathing it. The internet wouldn't be the magical resource it is without treasures like you. Love your work and looking forward to the post of the "wild" ones in February, thanks again :)
Asaruludu · 3 points · Posted at 16:01:49 on January 9, 2016 · (Permalink)
It's not just the grade-school education system, either. I had a professor in university who, when I asked for the reasoning behind some aspect of matrix calculations (don't remember what - it was a long time ago), told me "because it's the rule. You have to do it this way or you get the wrong answer."
I struggled in that class for weeks, until a programming lab instructor had me mess with the matrix calculations for a 3D animation. If you did it wrong, you'd end up moving the object to the right instead of rotating it, or turning it inside out instead of moving it forward.
My grades in that class went from 60 to 95 in the span of 10 minutes.
lucasvb · 1 points · Posted at 16:03:20 on January 9, 2016 · (Permalink)
Yep. A lot of teachers have no idea why things are the way they are either. Hard to expect understanding from a mentor who doesn't understand things themselves.
It's a hard thing to change. :(
votes_the_goats · 2 points · Posted at 15:52:23 on January 9, 2016 · (Permalink)
You are seriously really great. I ended up in a field that barely uses math at all, but for quite some time have wished to relearn what I learned in school, and more. Is there a place you would recommend starting?
lucasvb · 3 points · Posted at 16:01:17 on January 9, 2016 · (Permalink)
Sadly, I don't know much in terms of recommendations.
There's little things that can be helpful here and there around the internet, but there's no single resource that goes through everything from the basics upwards in a way that I think it is outstanding. At least none I'm aware of.
What I do recommend is never giving up on a concept and "just memorizing it", because everything HAS to make sense. To achieve this, just expose yourself to as many explanations of a topic and think hard about it until something sticks. That's what I've done.
sturmhauke · 1 points · Posted at 20:48:26 on January 9, 2016 · (Permalink)
Knowing a bunch of facts doesn't necessarily make you smart. Knowing how they fit together, and being able to make useful decisions based on that, does.
iambrock · 1 points · Posted at 13:50:50 on January 9, 2016 · (Permalink)
Thank you.
Teomalan · 1 points · Posted at 14:15:08 on January 9, 2016 · (Permalink)
As a parent who had no problems 20 years ago, but has a heck of a time explaining them to my teenager, thank you!
Warbandit · 1 points · Posted at 14:42:30 on January 9, 2016 · (Permalink)
I think it's sort of telling that that gif felt like cheating because I understood it so quickly, and yet struggled with math all through middle and high school. Thanks for a mini-confidence booster first thing in the morning!
juletre · 1 points · Posted at 18:37:46 on January 9, 2016 · (Permalink)
Have you sern Mathbox2 ? (Google mathbox death of powerpoint) . It talks about having animations in lectures, but eith the actual math being done and not a prerendered animation. It makes it easier to understand fractals as well.
lucasvb · 2 points · Posted at 18:38:53 on January 9, 2016 · (Permalink)
Yep. Steven Wittens and I have talked about collaborating somehow in the future.
juletre · 1 points · Posted at 22:19:23 on January 9, 2016 · (Permalink)
Cool. I'll be on the lookout for that!
blbd · 1 points · Posted at 19:05:19 on January 9, 2016 · (Permalink)
I am still waiting for project based learning to be adopted after several decades of studies repeatedly finding it better than the old way. But it will be difficult for any of these innovations to happen if we don't start taking teaching more seriously like Korea and Finland do. Right now we treat it as an expense instead of as an important investment.
poompk · 1 points · Posted at 00:23:09 on January 10, 2016 · (Permalink)
Thank you so much for doing the work you do. As a major fan of the subject, I also think the way math is taught in primary and secondary schools is horrendous and hope that we can all fix it someday. Just want to express my appreciation and hope you keep it up! :)
Dekar2401 · 1 points · Posted at 01:18:36 on January 10, 2016 · (Permalink)
You're awesome. Hopefully you can help make the logic of math visual for everyone who sees your work.
arterficial · 1 points · Posted at 13:37:22 on January 9, 2016 · (Permalink)
I don't see why these aren't used in school already. I love the simplicity of it, it's great!! This would have helped me so much when I was in school and imagine it being applied to other mathematical equations.
lucasvb · 1 points · Posted at 13:59:01 on January 9, 2016 · (Permalink)
Sadly, a lot of teachers aren't even aware of this geometric reasoning, and most people (students or teachers) don't look up stuff they are learning to get a different source/perspective.
heliotach712 · 35 points · Posted at 15:00:50 on January 9, 2016 · (Permalink)
geometry was 100% visualisation when the Greeks invented it, even Pythagoras's Theorem was proved visually. Thanks a lot Descartes, "analytic geometry", pffft
W_T_Jones · 3 points · Posted at 00:53:19 on January 10, 2016 · (Permalink)
You can't really prove things visually though. You can give a visual motivation as to why the theorem might be true but you can never prove it visually.
user_82650 · 8 points · Posted at 14:42:51 on January 9, 2016 · (Permalink)
I don't know how people can learn stuff without visualizing it.
To me they're practically synonyms.
alleigh25 · 1 points · Posted at 21:23:29 on January 9, 2016 · (Permalink)
Personally, I can't visualize things in my head. But that doesn't mean I don't get anything out of seeing things illustrated. If anything, I might need them more in some situations since I can't just picture it myself.
But when it comes to geometry specifically, my class was 1/2 visual and 1/2 proofs, and the heavy reliance on visuals was a little irritating to me because I much prefer just sitting down and doing math (see also: revolving solids and 3D molecular drawings, because rotating things is the worst). Yet, weirdly, when I had a class in college that went through Euclid's Elements, the completely visual proofs of everything were actually pretty awesome. It's weird how simple some of them are when you break them down to just straight lines and circles.
tehlaser · 2 points · Posted at 20:41:08 on January 9, 2016 · (Permalink)
That is a problem, but the other extreme is nearly as bad. Math education trends seem to alternate between "shut up and calculate" and "draw a map to the answer."
My time in geometry class in high school was almost all spent working with compass and straight edge. I have an OK grasp of how to visualize my way to an answer, but almost no idea how to explain or write about geometry, or proofs in general, which, along with an informal, hand-holdy (but very effective) calculus class ended up crippling my college math. I flunked discrete math three times before I finally figured out how to read a proof, and I only managed that by finding a discrete math class offered by the computer science department taught in Prolog.
It's unfortunate how teaching being "too good" in the short term can fail so badly to prepare one to learn on their own.
psychoanalogy · 2 points · Posted at 02:27:17 on January 10, 2016 · (Permalink)
I truly believe too many people are not reading the book.
Reading is fundamental in our society but I think people have learned in the public education system especially that the job of a teacher is to be a tour guide, and to hold your hand and spoon feed you things a little at a time.
Reading is like exploring, in many other disciplines and in professional life you have to read read read, and explore.
Teachers are there to talk to you when you just can't make it work on your own and you need somebody to wave their arms around and chat with you.
Not to say everyone doesn't have different styles of learning, just saying all styles of learning are part of the whole of learning and they all should be practiced for highly effective learning.
tehlaser · 2 points · Posted at 04:22:37 on January 10, 2016 · (Permalink)
Indeed.
You are the first person who has ever suggested reading a math textbook to me. Every math teacher I have ever had used the text only as a source of exercises. My high school calculus teacher even told me not to read it because it was "too complicated and impossible to understand." Some of my college professors even told their classes to return their books if they bought them because, although required by policy, they would never be used.
psychoanalogy · 1 points · Posted at 08:20:40 on January 10, 2016 · (Permalink)
hs calculus? what the hell?
read the book people! shit : [
tehlaser · 1 points · Posted at 08:40:57 on January 10, 2016 · (Permalink)
She wasn't wrong. I knew so little notation I couldn't even have read most of the lessons aloud, let alone understand them. At the time the only Greek letters I could recognize were lowercase pi and theta.
Arzetaire · 2 points · Posted at 14:12:26 on January 9, 2016 · (Permalink)
In school right now and I've come to accept some math. My teacher is not very visual.
reallymobilelongname · 1 points · Posted at 19:32:20 on January 9, 2016 · (Permalink)
Of course they aren't, we weed the ones who are out by only providing numerals not visuals to work with.
_beardyman_ · 41 points · Posted at 15:25:52 on January 9, 2016 · (Permalink)*
30 seconds ago I'm just a guy taking a shit. Now? I'm a guy taking a shit who knows what a mothafuckin rad is
Dabfo · 13 points · Posted at 13:16:18 on January 9, 2016 · (Permalink)
This gif should be required in math classes teaching this concept. So simple yet so often not taught correctly or at all.
lucasvb · 10 points · Posted at 13:55:19 on January 9, 2016 · (Permalink)
Yeah, it's disgraceful that this concept is so often taught without a single illustration.
Aerroon · 1 points · Posted at 14:14:26 on January 9, 2016 · (Permalink)
I don't understand - what does this tell you? I mean by the definition of radians you would understand this. And every time you convert from degrees to radians or vice versa you would use this knowledge.
Every time I have seen this animation posted I've seen people say that it suddenly clicks for them but I don't understand what they "get". I feel like I'm still missing it, because this definitely did not make me suddenly understand radians more intuitively or want to use radians more.
SGlyko · 20 points · Posted at 14:30:50 on January 9, 2016 · (Permalink)
People learn differently. You're like me - verbal descriptions are usually enough to explain a concept. You hear, "A radian is the measure of the angle such that the arc created is equal to the length of the radius" and you can essentially draw that gif in your mind. We're not all wired the same way, so some people get lost in that word-soup and are much more easily able to understand by way of an illustration. You and I may not need that illustration, but that doesn't mean we're smarter, more talented, or better than the folks that understand better with the animation - we just learn differently.
Dabfo · 9 points · Posted at 14:55:04 on January 9, 2016 · (Permalink)*
That's not it. I'm well past getting it, but I remember having high school teachers and even a fair amount if professors that teach concepts and expect students to remember them by wrote memorization instead of explaining the reasoning behind it.
I would bet money that 180 deg = 2 pi is taught more than taking the extra 5 min to explain why, as this simple gif elegantly shows.
It is the same for sinusoidal waves and lots of other concepts. I remember Fourier transforms not clicking until I started working with spectrum analyzers in the lab almost 10 years after I struggled through them in college. I walked out of that class with an "A" and no idea how to apply it because it was all memorization and knowing just enough to get by, but not enough understanding to see the beauty of the application.
Too many teachers teach just enough to move on to the next concept, not caring to show some of the simple elegance of the concepts.
Edit: leaving my math error to show my shame
christian-mann · 1 points · Posted at 18:22:07 on January 9, 2016 · (Permalink)
Psst... 180 deg = pi, not 2pi
Dabfo · 1 points · Posted at 18:35:13 on January 9, 2016 · (Permalink)
Doh! That's what I meant. I will leave it to show the danger of text only learning.
rightfulemperor · 14 points · Posted at 13:17:47 on January 9, 2016 · (Permalink)
This gif would have taught me better than any textbook.
piratius · 3 points · Posted at 15:18:11 on January 9, 2016 · (Permalink)
Or the teacher could explain that one radian is equal to the length of the radius around the circumference.
No one ever told me, but just saying it that way would've made instant sense, even though radians are a dumb unit.
Dharmasabitch · 4 points · Posted at 19:34:16 on January 9, 2016 · (Permalink)
Radians are not a dumb unit! Degrees are the dumb unit! Breaking things into 360 is Babylonian garbage. This way, all you have to do to find the length of a circular arc is multiply its angle in radians by the radius of the circle!
piratius · 3 points · Posted at 21:22:18 on January 9, 2016 · (Permalink)
I was being slightly sarcastic. Saying ".35 radians" as an angle is a lot less obvious than using 15 degrees, since the scale of the unit doesn't natively lend itself to easy mental math.
Like saying .05 kilometers instead of 50 meters, it's the same thing, it's just one is easier to manipulate in your head because it uses integer numbers and the scale is more appropriate.
Having ~6.28 radians per circle is just an awkward number to try to subdivide, was my point, not that it doesn't have its uses.
Dharmasabitch · 1 points · Posted at 23:28:55 on January 9, 2016 · (Permalink)
That's true. I'm definitely biased because I come from a math background, but I can see how maybe an engineering person would find the numbers unnecessarily awkward.
RandallOfLegend · 24 points · Posted at 13:53:23 on January 9, 2016 · (Permalink)
I have a Masters degree in Mechanical engineering. I never knew this about radians, I just took it for granted. Awesome depiction!
LastStar007 · 12 points · Posted at 18:37:50 on January 9, 2016 · (Permalink)
So the fact that circumference = 2pi * radius never rang any bells?
Dharmasabitch · 14 points · Posted at 19:32:37 on January 9, 2016 · (Permalink)
I'm seriously confused how people are responding to this as if its new insight. Isn't this what they always teach when they introduce radians in school?
[deleted] · 26 points · Posted at 20:43:01 on January 9, 2016 · (Permalink)
Nope, it's just another equation to memorize when the teacher doesn't care enough to explain it
Fastco · 2 points · Posted at 22:14:36 on January 9, 2016 · (Permalink)
Yeah I can understand that in lower level classes but I mean when you have to do differential equations in polar coordinates I would think you would have a basic understanding of them? Maybe me and my friends were an exception.
Ninja Edit: Also in one of my trig classes we were taught to ALWAYS use radians, you would think people would understand what they are by working with them so much
alanwj · 3 points · Posted at 02:59:58 on January 10, 2016 · (Permalink)
I've always felt we should just call them "radiuses" instead of "radians", to drive the point home.
Fastco · 1 points · Posted at 19:15:59 on January 10, 2016 · (Permalink)
I think it is close enough as it is, besides in general its best to not name two different things the same. Radians are a unit of angle, and radiuses are the length of a specific thing. I think the biggest problem is our teaching of equations without giving the underlaying knowledge behind them.
[deleted] · 2 points · Posted at 00:23:58 on January 10, 2016 · (Permalink)
We're talking average students here, who never need to take differential equation classes in polar coordinates--I assume most people who get to that point are familiar with how radians work.
It's not that they were taught to use radians, it's just it was never explained what a radian really is.
It's like using x = -b/2a for quadratic functions--it's just an equation (but people who take calculus will be able to derive that).
Fastco · 1 points · Posted at 19:11:02 on January 10, 2016 · (Permalink)
I guess I was mainly replying to the dude who said he has a masters in Mechanical Engineering, tell me that dude didn't do a shit load of differential equations in polar coordinates. Source: former mechanical engineering student
RandallOfLegend · 3 points · Posted at 01:28:40 on January 10, 2016 · (Permalink)
Some people learned what it was in high school and never used it, then eventually became one of those math buzzwords they recognize. Not everyone on reddit is young enough to recall this either. Been 15 years since I took basic trigonometry.
TheFrigginArchitect · 2 points · Posted at 23:00:06 on January 9, 2016 · (Permalink)
If you teach something to millions of people, some will miss it
chelseabreadman · 2 points · Posted at 20:32:51 on January 9, 2016 · (Permalink)
No.
RandallOfLegend · 2 points · Posted at 01:26:06 on January 10, 2016 · (Permalink)
It's the difference between knowing the equation and understanding it. As an engineer radians has been an inconvenient conversion I have to do, never given it any deeper thought. Also, after years of calculus, vector math, and fluid mechanics you push things like this out of your head. Writing the Navier-Stokes equation in non-cartesian coordinates will cause a surprising mental purge.
lucasvb · 2 points · Posted at 14:07:17 on January 9, 2016 · (Permalink)
I'm glad I could offer such insight!
DashingLeech · 1 points · Posted at 01:00:38 on January 10, 2016 · (Permalink)
This is also why arc length s = r•theta only works in radians. It's a simple ratio since the arc length of 1 radian is radius r:
s/r = theta(radians)/(1 radian)
We just leave the 1 out of it since it's mathematically superfluous. But the canceling of units is why it must be radians.
You can, of course, do a similar ratio using other units for angles, but the number of angular units on the bottom must correspond to an arc length equivalent to the radius, hence it's no different from just putting in the "radian to other units" conversion formula into the above equation.
wickedevil · 6 points · Posted at 12:58:26 on January 9, 2016 · (Permalink)
Thanks for the gif!
aidanski · 7 points · Posted at 13:09:34 on January 9, 2016 · (Permalink)
Great job, your simple visualisations of these mathematical concepts are excellently presented.
lucasvb · 1 points · Posted at 13:22:01 on January 9, 2016 · (Permalink)
Thanks!
dubyahhh · 8 points · Posted at 13:26:19 on January 9, 2016 · (Permalink)
I tutor physics (I'm an engineering student that was helped by this gif too actually!) And I use this whenever someone doesn't understand conversions between radians and degrees. So thanks!
lucasvb · 2 points · Posted at 13:57:53 on January 9, 2016 · (Permalink)
Glad to be of help!
amart591 · 5 points · Posted at 14:33:51 on January 9, 2016 · (Permalink)
As a math tutor, thank you. I have an opportunity to sit down with kids one on one and really teach them math and gifs like these are a vital part to that. I wish they would be taught this in school but they aren't even though their textbooks and homework are already digital. Even for me as an engineering major find these helpful and its sad that I wasn't shown these when I was their age. We could all have a much better grasp of the math around us if we finally stop the whole "memorize a formula and plug in numbers" system we have now.
lucasvb · 10 points · Posted at 14:39:51 on January 9, 2016 · (Permalink)
You're welcome!
You know what really saddens me? Imagine how many people have set in their heads their entire lives that they're just "too dumb" for math, when all they needed was someone putting the effort to explain things more clearly.
For as long as I'm alive I'll try to fix this situation.
SexyGeniusGirl · 1 points · Posted at 17:21:02 on January 9, 2016 · (Permalink)
That is a great thing to do with your life. Thank you.
c_m_d · 1 points · Posted at 00:35:13 on January 10, 2016 · (Permalink)
I had to sign in to upvote this. Also, I needed to thank you for your work.
sequinsandglitter · 1 points · Posted at 04:35:19 on January 10, 2016 · (Permalink)*
deleted What is this?
sinksank · 1 points · Posted at 15:19:40 on January 9, 2016 · (Permalink)
We're starting to move towards a more conceptual understanding of math in the K-12 curriculum. Common Core standards place more emphasis on conceptual understanding and a lot of the new curriculum being used now has a lot more of that (along with teaching standard algorithms). It's not perfect but it's a start.
TheBurningBeard · 27 points · Posted at 14:03:36 on January 9, 2016 · (Permalink)
I'll be honest. If I had seen that explanation in high school, I might be in a different profession.
Thingler · 5 points · Posted at 13:11:44 on January 9, 2016 · (Permalink)
I'd also like to know, what software you used to make that gif, adobe flash? or was it something else?
lucasvb · 3 points · Posted at 13:21:54 on January 9, 2016 · (Permalink)
Check this comment.
[deleted] · 3 points · Posted at 14:14:53 on January 9, 2016 · (Permalink)
[deleted]
lucasvb · 2 points · Posted at 14:21:23 on January 9, 2016 · (Permalink)
I think so too. Our system is messed up, and we're stuck in ancient methods and traditions.
I think we need to gather around the best math teachers around, as well as a bunch of motion and graphic designers, and figure a way to tackle the subject in new ways using modern technology. We have so much more opportunities for teaching!
This is why I'm so deeply unsatisfied with the typical YouTube channel that teaches math and physics. They end up using video to reproduce traditional lectures. It's such a waste.
cos · 2 points · Posted at 13:42:51 on January 9, 2016 · (Permalink)
Your GIFs are great! Would you consider making YouTube video versions, so they can be played on more devices, and people could pause them or go slowly back and forth?
lucasvb · 5 points · Posted at 14:03:31 on January 9, 2016 · (Permalink)
Well, not exactly. I could reupload them as videos to YouTube, sure. You can find a few in my personal YouTube channel
But I'm currently working on another YouTube channel where I'll use technical animations and narration to explain math and physics in a more advance way, but still aimed at general audiences.
My plan is to cover most of the subjects in these GIFs, but more in-depth and building up to them.
[deleted] · 2 points · Posted at 14:06:31 on January 9, 2016 · (Permalink)
Oh, well then i'll just c&p my other comment for you:
SuperMoquette · 2 points · Posted at 14:32:07 on January 9, 2016 · (Permalink)
Thanks to your gif I've finally understand something I'm struggling since high school.
Keep on doing such beautiful explanations sir !
lucasvb · 1 points · Posted at 14:37:03 on January 9, 2016 · (Permalink)
Awesome. I'm glad I could help!
brianlouis · 2 points · Posted at 14:35:28 on January 9, 2016 · (Permalink)
God I wish there were math gifs back when I was in school. I would have understood, and probably enjoyed, much much more of my math and science classes. Thank you for your work on those.
fucky_fucky · 2 points · Posted at 14:50:40 on January 9, 2016 · (Permalink)
I was the same as him. Your animations are dope. After I found out that you were the guy making the majority of those animations, I spent an hour looking at the rest of them. I wish you had animations for everything!
Roccobot · 2 points · Posted at 15:11:18 on January 9, 2016 · (Permalink)
I find amazing that you were reading this post so you can receive some of the glory you deserve.
[deleted] · 2 points · Posted at 15:11:29 on January 9, 2016 · (Permalink)
I've been an engineer for five years and i just get it now. Whoa.
Thank you!
French__Canadian · 2 points · Posted at 15:13:16 on January 9, 2016 · (Permalink)
With an s? Do you have one for Fourrier transforms?
lucasvb · 1 points · Posted at 15:20:06 on January 9, 2016 · (Permalink)*
Yep. Check my Wikipedia gallery and my Tumblr.
I've tried a few stuff on Fourier transforms, but I don't think I've nailed it yet. Yet! :D
JeahNotSlice · 2 points · Posted at 15:24:55 on January 9, 2016 · (Permalink)
Math teacher here. I have seen many gifs that are similar to this. Yours is my new favourite. Thanks so much.
[deleted] · 2 points · Posted at 15:38:51 on January 9, 2016 · (Permalink)
That's a super helpful gif, man. Great job!
drinks_antifreeze · 2 points · Posted at 15:47:22 on January 9, 2016 · (Permalink)
Whoa LucasVB it's you! Huge fan of your work here. Your cross product gif was a life saver in calc 3.
InfintySquared · 2 points · Posted at 15:49:01 on January 9, 2016 · (Permalink)
THANK YOU. I actually came across this gif about a year ago, and "it just clicked."
I'm from a family of teachers and I mentor myself, so I'm ALWAYS looking for a new analogy to explain an idea. This was freaking awesome.
Edit: Checking your edit... Yeah, when I saw this I did follow through to your Wikipedia gallery, and a lot of stuff did make a lot of sense then. Thank you, keep on rockin' in the free world.
nomadthoughts · 2 points · Posted at 15:49:29 on January 9, 2016 · (Permalink)
Fuck! I am a fucking Engineer and didn't know how this shit worked. Thank you so much, dude. Mind fucking blown.
lucasvb · 2 points · Posted at 15:50:20 on January 9, 2016 · (Permalink)
You're welcome!
Eiramasil919 · 2 points · Posted at 15:52:00 on January 9, 2016 · (Permalink)
This is so great for my kids! It's so abstract when you first start learning geometry. Thank you!
nplakun · 2 points · Posted at 15:52:34 on January 9, 2016 · (Permalink)
Where have you been all my mathematic life? This is exactly- and I mean precisely- what I needed to cement and internalize my conceptual understanding on many of these points. Thank you.
JakeyG14 · 2 points · Posted at 15:58:57 on January 9, 2016 · (Permalink)
Dudes like you make learning/teaching far easier.
MyDickIsMeh · 2 points · Posted at 16:18:24 on January 9, 2016 · (Permalink)
I didn't realize the relationship either. Thanks!
Can't wait to check out the rest of your stuff.
sadcosmonaut · 2 points · Posted at 16:19:29 on January 9, 2016 · (Permalink)
I wish I had seen this in high school. That gif explains it better than any teacher I ever had.
lets_trade_pikmin · 2 points · Posted at 16:23:37 on January 9, 2016 · (Permalink)
Wow, I've actually encountered a good number of these in the past. Didn't realize they were all by the same dude! Great work here, these are always the most helpful part of a wikipedia page.
Squirrelthroat · 2 points · Posted at 16:37:21 on January 9, 2016 · (Permalink)
248th subscriber on your youtube site. Awaiting good vid's :D
lucasvb · 1 points · Posted at 16:39:41 on January 9, 2016 · (Permalink)
Oh god, what have I done.
Squirrelthroat · 1 points · Posted at 21:26:05 on January 12, 2016 · (Permalink)
you better come up with something good ^ ^ You've got 2.354 subscribers to please now.
ndg127 · 2 points · Posted at 16:43:31 on January 9, 2016 · (Permalink)
I teach pre-calc and I show this to my students every tone they learn the unit circle! I was so happy to find it on the internet.
PM_Me_Yer_Guitar · 2 points · Posted at 16:48:58 on January 9, 2016 · (Permalink)
I honestly think I just understood like 7 things I didn't know before. Not even related to geometry. Like how my vacuum works and why yellow and blue make green. Don't know how you did that.
Chand_laBing · 2 points · Posted at 16:53:20 on January 9, 2016 · (Permalink)
Wow, I've seen so many of your .gifs but didn't realise they all came from the same person!
you're like wikipedia famous n shit
lucasvb · 2 points · Posted at 16:56:47 on January 9, 2016 · (Permalink)
So people keep telling me. I guess I should wear that "I'm important on the Internet" shirt?
Chand_laBing · 1 points · Posted at 17:42:26 on January 9, 2016 · (Permalink)*
Oh yeah deffo, you could get this outfit too
Srsly tho, I'm very impressed by your gifs, they really are some of the clearest explanations of maths I've ever seen, I really like your Fourier Analysis ones.
What kind of software do you use to make them? I've been doing still graphics for a while and have wanted to get into animation but I'm not sure what would be best to start withNever mind, I found the comment where you sayif you make one showing that a cat is homeomorphic to a coffee cup, you'd become like an internet God or something
lucasvb · 2 points · Posted at 18:03:50 on January 9, 2016 · (Permalink)
Shit, it took me forever to find the parametric equation for a coffee cup. Imagine how long it's going to take me for a cat!
Chand_laBing · 2 points · Posted at 18:12:32 on January 9, 2016 · (Permalink)
Aww man :(
Have you tried using meowtivariable calculus?
lucasvb · 2 points · Posted at 18:17:34 on January 9, 2016 · (Permalink)
Only cat-egory theory.
Pdubs2_0 · 2 points · Posted at 17:02:45 on January 9, 2016 · (Permalink)
You made the circle gif! It's what really made cosine and sine click for me.
lucasvb · 1 points · Posted at 17:04:14 on January 9, 2016 · (Permalink)
It's what everyone should see beforehand.
KWiP1123 · 2 points · Posted at 18:04:09 on January 9, 2016 · (Permalink)*
You are amazing.
All through high school and well into college, Trigonometry never clicked with me. In fact, that's a big factor as to why I got frustrated with school and dropped out after my associate's.
I just want to say, that if I had been shown something like this when I was in high school, I think the effects it could have had on my future academic career are incalculable.
Seriously, if you get the opportunity, see if you can't work with schools or textbooks or some educational programs. If you can get this into classrooms, I don't think there's a limit on how many students might be helped by this.
Keep being awesome.
edit - missing if
lucasvb · 2 points · Posted at 18:22:25 on January 9, 2016 · (Permalink)
One of my long term goals is to lead an effort to completely reconstruct the entire math, physics and chemistry curriculum up to 2nd year college at least.
Preferably if all this material eventually becomes public domain so nobody else ever has an excuse to teach using shitty resources.
MrWoohoo · 2 points · Posted at 18:22:49 on January 9, 2016 · (Permalink)
Are you a fan of Jim Blinns Mechanical Universe? "Remember this equation, you'll need it later..."
lucasvb · 2 points · Posted at 18:31:35 on January 9, 2016 · (Permalink)
Fuck yeah, huge fan. It's amazing.
[deleted] · 2 points · Posted at 18:29:30 on January 9, 2016 · (Permalink)
[deleted]
lucasvb · 2 points · Posted at 18:35:27 on January 9, 2016 · (Permalink)
I had plans on a proper countour integral set of animations, but I never got around to it. I felt I needed to study complex analysis a bit more formally to be up to par.
ODGlenchez · 2 points · Posted at 19:20:19 on January 9, 2016 · (Permalink)
Thank you! I've seen your work before but I was on mobile so I couldn't bookmark your gallery. I'm about to be a high school math/physics teacher and am SO planning on shoehorning these in somehow. Your animations and http://betterexplained.com/ are great for non-math-heavy explanations of processes and phenomena.
I really liked this explanation of sine and cosine for students.
JustinianTheWrong · 2 points · Posted at 19:20:22 on January 9, 2016 · (Permalink)
This is a fantastic gif! My AP Calc teacher did almost the same demonstration with colored markers on a whiteboard and it really helped everything make a lot more sense. I'm sure your gif is going to give people a lot of "a-ha" moments, and that's awesome!
Master4pprentice · 2 points · Posted at 19:21:04 on January 9, 2016 · (Permalink)*
Cool animations!
I used to make some animations of my own in my time as a physics student. I mostly used Wolfram mathematica since it was easy to use with programming AND drawing, but it does have some limitations. Your animations look way more elegant!
Anyways, if you want, you can check out my animations on the bottom links and you have my full permission to copy any ideas or reanimate them if you think they're worth it, I would like to see them done in your style!
Random collection
Eigenmodes collection
Ant exploring 3D
Some experiment with a 3D visualiser
lucasvb · 1 points · Posted at 19:29:35 on January 9, 2016 · (Permalink)
Your animations are way cooler than mine. Those simulations in the random collection are great!
I need to learn how to write proper simulations.
Master4pprentice · 2 points · Posted at 20:51:03 on January 9, 2016 · (Permalink)
I wouldn't go exactly as far as cooler, but thanks :)
Well, if you ever need any help with physics simulations for your YT channel, I'd be honoured to help!
realigion · 2 points · Posted at 19:29:25 on January 9, 2016 · (Permalink)
i love you
[deleted] · 2 points · Posted at 19:33:52 on January 9, 2016 · (Permalink)
You are the author of eigenvector animation?
Dude, I am soooo thankful for that animation. So brilliant and simple. I have linked it on my twitter account and said "where was this animation when I was taking Lin ALgebra 10 years ago"
Thank you again.
lucasvb · 2 points · Posted at 19:35:32 on January 9, 2016 · (Permalink)
You're welcome!
Araeven · 2 points · Posted at 19:48:30 on January 9, 2016 · (Permalink)
After multiple years of calculus rads finally make sense. Wish I had seen this in my first year of university, it would have made life easier
iloveapple314159 · 2 points · Posted at 19:51:34 on January 9, 2016 · (Permalink)
Have an upvote for being awesome!
pens297187 · 2 points · Posted at 21:37:11 on January 9, 2016 · (Permalink)
Thank you for teaching me more with a 15 second clip then my high school math teacher could with a whole school year.
MAK911 · 2 points · Posted at 01:14:07 on January 10, 2016 · (Permalink)
Sent to my Calculus teacher. Class makes a bunch more sense because of your animatioms. Thank you!
breawycker · 4 points · Posted at 14:19:49 on January 9, 2016 · (Permalink)
Woo! Wikipedia editors unite! I feel bad, because it's been so long since I've done any editing. High school just takes up too much time.
WikiWantsYourPics · 2 points · Posted at 14:37:33 on January 9, 2016 · (Permalink)
Slashme checking in.
breawycker · 2 points · Posted at 14:44:40 on January 9, 2016 · (Permalink)
Ooh. I like your Reddit username.
FolkSong · 3 points · Posted at 15:53:40 on January 9, 2016 · (Permalink)
PhD in electrical engineering here, I never made that connection (radius<->radian) until now.
[deleted] · 1 points · Posted at 13:20:29 on January 9, 2016 · (Permalink)
[deleted]
lucasvb · 1 points · Posted at 13:57:16 on January 9, 2016 · (Permalink)
Aww, c'mere. *hug*
[deleted] · 1 points · Posted at 13:26:53 on January 9, 2016 · (Permalink)
Holy shit this makes so much sense now.
[deleted] · 1 points · Posted at 13:50:44 on January 9, 2016 · (Permalink)
Many thanks. That's so rad.
SneezyDeezyMc_Deluxe · 1 points · Posted at 13:52:00 on January 9, 2016 · (Permalink)
It is beautiful. Thank you.
fivestringsofbliss · 1 points · Posted at 13:56:12 on January 9, 2016 · (Permalink)
If I had this GIF last year, I wouldn't have had to switch majors
[deleted] · 1 points · Posted at 14:01:11 on January 9, 2016 · (Permalink)
thank you... thank you so much
chasemuss · 1 points · Posted at 14:04:02 on January 9, 2016 · (Permalink)
You, sir or madam, are the reason I love math. Thank you so much.
Coffeinated · 1 points · Posted at 14:06:56 on January 9, 2016 · (Permalink)
Why would you rename r to rad? Writing 2pi r would have made sense as well
lucasvb · 2 points · Posted at 14:11:00 on January 9, 2016 · (Permalink)
I didn't rename anything.
The circle can have any radius. That's why I called the radius r.
The "rad" in there is for specifying the unit of "radians".
Note that some people will say that radians are "unitless", but that's incorrect. Radians are dimensionless units, and so are degrees. A unit is just a standard you use for measuring something, so specifying it can be important.
Also note that I take a lot of care in color coding things. The r and the red arc are red because they are related. The angle and the "rad" are green because they are related.
Coffeinated · 1 points · Posted at 14:15:30 on January 9, 2016 · (Permalink)
Ah okay, we don't really use the term or unit radians. A circle is just 2 π, that's it... At lesst in my university in germany
lucasvb · 1 points · Posted at 14:19:41 on January 9, 2016 · (Permalink)
Radians are usually understood by context. The fact they are dimensionless also means you don't have to worry about dimensional analysis.
It is convention to understand an angle of "x" as x radians, but making it explicit won't hurt, especially to those who are learning.
shbk · 1 points · Posted at 14:11:39 on January 9, 2016 · (Permalink)
That's rad
[deleted] · 1 points · Posted at 14:11:40 on January 9, 2016 · (Permalink)
[deleted]
lucasvb · 1 points · Posted at 14:13:31 on January 9, 2016 · (Permalink)
Yep. Pi radians is half of the circle.
Pi is about 3.141592... so you can fit 3 radii around half the circle, but there's still 0.141592 of a radius left to complete it.
This is why pi has the value it has.
phenixreborn · 1 points · Posted at 14:17:05 on January 9, 2016 · (Permalink)
Why can't you teach everything everywhere?
TheTalentedMrBryant · 1 points · Posted at 14:17:39 on January 9, 2016 · (Permalink)
That was fantastic! Thankyou!
SendMeYourSoul · 1 points · Posted at 14:20:24 on January 9, 2016 · (Permalink)
You da real mvp
Timothy_Claypole · 1 points · Posted at 14:22:40 on January 9, 2016 · (Permalink)
This needs to be played to 16 year olds so they understand then, and don't have to wait till later.
lucasvb · 1 points · Posted at 14:28:46 on January 9, 2016 · (Permalink)
I agree. What bothers me is that there's no excuse to not offer this kind of resource to kids these days. Everyone has a computer.
DigiDuncan · 1 points · Posted at 14:27:04 on January 9, 2016 · (Permalink)
What program did you use to create this animation? It's very fluid and pretty to watch.
lucasvb · 1 points · Posted at 14:30:04 on January 9, 2016 · (Permalink)
Check this comment.
But the animation isn't really a software issue. I'm a big fan of traditional animation and I'm super into motion design. I try very hard to use these principles in the stuff I do, to make the animations as effective as possible as educational content.
It's a lot of extra effort, but it really pays off, judging from the reaction of many people.
Grizzly_Berry · 1 points · Posted at 14:32:06 on January 9, 2016 · (Permalink)
Dude that's rad!
bobbertmiller · 1 points · Posted at 14:32:35 on January 9, 2016 · (Permalink)
I have my engineering degree and I've only seen this afterwards. I never knew the connection. I just accepted that it's 2pi all around. I wonder how much else was just taught badly and thus didn't click back in the school time.
charliem76 · 1 points · Posted at 14:34:54 on January 9, 2016 · (Permalink)
Well out of school at this point, but I just had a 'whoa' moment.
delhux · 1 points · Posted at 14:42:21 on January 9, 2016 · (Permalink)
Totally rad!
GIGATeun · 1 points · Posted at 14:44:56 on January 9, 2016 · (Permalink)
Hey, do you mind explaining how you made this one? Specifically the bending around its own axis part. I often try to make mathematical animations myself too but I can't wrap my head around how this is done. Also, thanks for your hard work on all the gifs!
lucasvb · 1 points · Posted at 14:58:31 on January 9, 2016 · (Permalink)
Sure.
The vertical lines are actually very large circles with centers way to the left. I figured how to scale them "linearly" from infinity, reducing their radii while moving their centers to the left.
This is done with a "t" parameter that goes from 0 to 1. At zero, the radii of all circles is zero and their centers are at the origin.
The function is mapped in a modified polar coordinate system based on the circumference of these large circles, instead of the angle from the origin. Took a few napkin sketches and GeoGebra simulations to get all of this right.
I don't think I have the source code around right now, otherwise I'd show you.
GIGATeun · 1 points · Posted at 16:54:57 on January 9, 2016 · (Permalink)
Ah, that's a very interesting way! I was playing around a bit and got this
MaggotCorps999 · 1 points · Posted at 14:53:02 on January 9, 2016 · (Permalink)
You're the bestest.
x_Zoyle_Love_Life_x · 1 points · Posted at 14:57:49 on January 9, 2016 · (Permalink)
Business major so I don't need to know radians anymore, but it still clicked fam!! Good job on that gif!
[deleted] · 1 points · Posted at 15:01:09 on January 9, 2016 · (Permalink)
You're a god among men
[deleted] · 1 points · Posted at 15:01:16 on January 9, 2016 · (Permalink)
Thank you for making it slow enough to follow along.
lucasvb · 2 points · Posted at 15:04:22 on January 9, 2016 · (Permalink)*
I put A LOT of effort in the animation timing and pauses, as well as the color coding. It pays off tremendously for animations.
It really pisses me off when educational animations are too fast, have a bunch of labels the user needs to read simultaneously, or don't pause long enough for each step to sink in. It's such a waste of efforts!
[deleted] · 2 points · Posted at 15:08:16 on January 9, 2016 · (Permalink)
Leaving the big pause at the end, and colouring the labels go match the diagram... It is the best!
Dinah_Mo_Hum · 1 points · Posted at 15:05:12 on January 9, 2016 · (Permalink)
I'm having a mathgasm!
heronumberwon · 1 points · Posted at 15:12:48 on January 9, 2016 · (Permalink)
Awesome thanks for this
swingking8 · 1 points · Posted at 15:23:26 on January 9, 2016 · (Permalink)
What do you use to make these visualizations?
auritus · 1 points · Posted at 15:31:02 on January 9, 2016 · (Permalink)
Great work!!!
ITRAINEDYOURMONKEY · 1 points · Posted at 15:36:36 on January 9, 2016 · (Permalink)
Great work! Even after doing undergrad in physics, this gave me a great, "Ohhhhh! moment. Keep it up!
andrewharlan2 · 1 points · Posted at 15:37:15 on January 9, 2016 · (Permalink)
Most importantly, how do you pronounce GIF?
lucasvb · 2 points · Posted at 15:42:13 on January 9, 2016 · (Permalink)
GIF. Sounds way better than JIF.
andrewharlan2 · 1 points · Posted at 15:57:47 on January 9, 2016 · (Permalink)
DAMNIT. Well, thanks for it anyway! Helped me understand how radians work and why they're called that.
UselessFactOrFiction · 1 points · Posted at 15:43:21 on January 9, 2016 · (Permalink)
Question, I am assuming that the small piece of the rad is .14~. Is that correct?
lucasvb · 1 points · Posted at 15:44:58 on January 9, 2016 · (Permalink)
That's correct!
I'm going to update the animation sometime in the near future to make that more explicit. I really shouldn't have shrunk the red arc in that section, as it breaks the general narrative.
I also should highlight that it's 3 + 0.1415..., and THEN write that it is equal to pi.
So there's still a lot of room for improvements here.
randomperson1a · 1 points · Posted at 15:56:05 on January 9, 2016 · (Permalink)
This is amazing, saving this.
sailingtowesteros · 1 points · Posted at 15:56:26 on January 9, 2016 · (Permalink)
I just saved your comment for future use! Thank so much!
ptr24 · 1 points · Posted at 15:57:22 on January 9, 2016 · (Permalink)
You the real MVP
DarkGamer · 1 points · Posted at 16:22:42 on January 9, 2016 · (Permalink)
Thanks for doing that, a lot of people don't consider the amount of work that can go into making those visualisations. They really help with learning.
CubbyHurlihee · 1 points · Posted at 16:24:46 on January 9, 2016 · (Permalink)
Why don't you make a subreddit for your stuff so we know when you make something new? I don't tumblr.
lucasvb · 1 points · Posted at 16:36:01 on January 9, 2016 · (Permalink)
It never occurred me that it would be useful or that there would be enough interest.
You could always just subscribe to the RSS feed of the Tumblr. Do you use feed readers?
CubbyHurlihee · 1 points · Posted at 16:42:16 on January 9, 2016 · (Permalink)
Gave up on RSS when google reader was murdered.
I think your visualizations are fantastic. I think you would find a lot of interest. You could crosspost to r/pics or other broad interest subs. r/engineeringporn would probably enjoy them as well, but it's nice to find these kind of visualizations all in one place.
beernaked · 1 points · Posted at 16:25:41 on January 9, 2016 · (Permalink)
These are really great. I find it really fun to try to simplify (or rather make more intuitive) explanations of things. I wish I coul dfind some way to just do that for the rest of my life. Can I ask what you do for a living?
lucasvb · 1 points · Posted at 16:32:37 on January 9, 2016 · (Permalink)
I'm currently a physics student, but what I do "for a living" is some occasional freelance coding and being frugal as fuck.
_UpstateNYer_ · 1 points · Posted at 16:27:25 on January 9, 2016 · (Permalink)
Ugh, you make my featured content on wiki seem so... underwhelming.
Nice work, keep it up.
Hazzardevil · 1 points · Posted at 16:27:51 on January 9, 2016 · (Permalink)
My Maths teacher is an idiot for never explaining it this way.
whofartedinmycereal · 1 points · Posted at 16:30:44 on January 9, 2016 · (Permalink)
That's great. Any way to animate an explanation of the adiabatic lapse rates?
lucasvb · 2 points · Posted at 16:34:06 on January 9, 2016 · (Permalink)
Probably. I love getting requests, but since I'm not a genius a lot of stuff goes over my head and would require a lot of effort to simply understand it well enough to make a proper animation.
I always add suggestion to my list, though.
Zheranon · 1 points · Posted at 16:32:08 on January 9, 2016 · (Permalink)
Thank you for the work you've done Bookmarking for the days my daughters start the hard homework. 😂
BeastlyDesires · 1 points · Posted at 16:32:39 on January 9, 2016 · (Permalink)
Thank you for working on these!
Geleemann · 1 points · Posted at 16:33:54 on January 9, 2016 · (Permalink)
Thank you
ashagari · 1 points · Posted at 16:36:20 on January 9, 2016 · (Permalink)
These are amazing! Much appreciated
imgettingfiredanyway · 1 points · Posted at 16:37:28 on January 9, 2016 · (Permalink)
The Creator... ; _ ;
cokert · 1 points · Posted at 16:39:09 on January 9, 2016 · (Permalink)
Subbed! Love this stuff, thanks for all your hard work!
savethetriffids · 1 points · Posted at 16:41:36 on January 9, 2016 · (Permalink)
Please continue the great work!
icedoverfire · 1 points · Posted at 16:41:46 on January 9, 2016 · (Permalink)
Solely because I'm "amateur mathing" if C = pi * D then all we're doing is subbing 2r for D? Hence 2pi radians in a circle?
Such a simple switch that confuses everyone lol
conquerer_ · 1 points · Posted at 16:44:16 on January 9, 2016 · (Permalink)
Make an iBook with iBook author
lucasvb · 1 points · Posted at 16:48:38 on January 9, 2016 · (Permalink)
Goes against my philosophy of having my content accessible anywhere by anyone. I'd rather have an interactive website.
conquerer_ · 1 points · Posted at 16:57:17 on January 9, 2016 · (Permalink)
You'd own it. I think you've got a real opportunity here because it's inventive thinking. The iBook would be interactive and show the animation. You'd basically have a trademark and copyright on the material.
Check out the iBooks Author conference if you're interested.
Regardless, great work.
Anfinset · 1 points · Posted at 16:48:02 on January 9, 2016 · (Permalink)
Good job! Keep it up!
Shanix · 1 points · Posted at 16:51:21 on January 9, 2016 · (Permalink)
You're a good person. Keep up the good work.
thnp · 1 points · Posted at 16:52:22 on January 9, 2016 · (Permalink)*
deleted What is this?
monsto · 1 points · Posted at 16:52:37 on January 9, 2016 · (Permalink)*
I've never been a math guy, but i never knew what the hell a radian was. Even after looking it up, the explanation was just bad. It's the Simple shit like this.
I haven't looked yet, as I'm on mobile, but do you have a gig of all the myriad ways that phi appears in nature?
lucasvb · 1 points · Posted at 16:56:19 on January 9, 2016 · (Permalink)
I wrote a post about it on Tumblr.
It has an interactive Flash applet, so it won't work on mobile, but the rest of the post should be fine. Be sure to check the applet once you're on a computer.
monsto · 1 points · Posted at 18:05:36 on January 9, 2016 · (Permalink)
as a (former) environment designer in video games, using phi was essential to making spaces feel right. I'm trying to impress this asthetic upon my kids.
PRiles · 1 points · Posted at 16:55:24 on January 9, 2016 · (Permalink)
Won't lie, that it makes some sense but I was confused at to why it got cut short at half and didn't just keep going around the full circle. But it was still very informative l, thank you.
lucasvb · 1 points · Posted at 16:58:51 on January 9, 2016 · (Permalink)
It got short because we decided π should be defined as circumference/diameter, instead of circumference/radius. So now the special constant we defined represents half of the circle in radians. Stupid.
This is why the proposal of τ = 2π as a circle constant (or, as I prefer, the angle constant) makes sense.
Check this post I wrote. It has the same animation but expressing τ.
BB-Guitar · 1 points · Posted at 16:57:04 on January 9, 2016 · (Permalink)
Actually, it's pronounced gif
DuplexFields · 1 points · Posted at 16:59:07 on January 9, 2016 · (Permalink)
Do you have a version with tau radians? I honestly believe this wouldn't have been such a revolutionary concept for so many commenters in this thread if 6.283 was taught in schools alongside pi. (Unlike /r/tau/ I believe they should both be taught.)
lucasvb · 1 points · Posted at 17:01:12 on January 9, 2016 · (Permalink)
Of course I made a tau version.
Here's my thoughts on the "Pi vs Tau" thing if you're interested.
DuplexFields · 2 points · Posted at 18:21:44 on January 9, 2016 · (Permalink)
You've written the best meta-discussion of tau I've ever read, and I agree with it. However, it's the section called "Dimensions" vs. "units" that really blew my mind. You've confirmed (and clarified) something I've long pondered.
For the past fifteen years I've been working on a philosophy I've been calling Triessentialism. I stumbled across the root concept in 2001, and my own "conceptual analysis" of it has shaped how I understand the world. Basically, there are three types of things: the Physical (the What), the Logical (the How), and the Emotional (the Why). They're fundamentally incommensurable (a word I learned thanks to you and Wikipedia), and they all play by their own rules. These concepts are imbedded in all philosophies across the millennia, usually hidden or badly grouped, but they're always there.
It's also a fractal ontology: each of the main categories has three similarly differentiated subcategories. I won't bore you with those details here, but you've just given me the key to my conceptual categorization of the physical: Mass ~= Physical (What), Time ~= Emotional (Why), Length ~= Logical (how). (Length must be measured against a standard rod, and is fundamentally rational. If this sounds like a cobbled-together explanation, I don't have space here to explain why it's not.) I'd previously matched up Mass = What and Time = Why, but not Length = How.
So, thank you for more than just the awesome animations!
MistahGustitues · 1 points · Posted at 16:59:34 on January 9, 2016 · (Permalink)
Thank you very much for what you do.
yanroy · 1 points · Posted at 17:07:51 on January 9, 2016 · (Permalink)
I'm an electrical engineer. I've been intimately familiar with radians for years. I intellectually knew everything in that gif, and yet I never would have been able to explain it to someone so elegantly. I can't put my finger on what I just learned, but it was important.
theacorneater · 1 points · Posted at 17:07:59 on January 9, 2016 · (Permalink)
thank you for doing it!
lichorat · 1 points · Posted at 17:09:45 on January 9, 2016 · (Permalink)
You make wikipedia amazing. I'm sure I've seen your work and loved it.
Chewbacca22 · 1 points · Posted at 17:10:44 on January 9, 2016 · (Permalink)
That was literally the most helpful piece of information I have ever seen for radians... Thank you!
bobby__joe · 1 points · Posted at 17:12:22 on January 9, 2016 · (Permalink)
I searched for an answer to this question but couldn't find it: what tools do you use to make these awesome gifs?
lucasvb · 1 points · Posted at 17:35:19 on January 9, 2016 · (Permalink)
Check this comment.
MC_Baggins · 1 points · Posted at 17:14:14 on January 9, 2016 · (Permalink)
Wow, really good job man, keep it up! Now if only you could teach me calculus the same way!
lucasvb · 2 points · Posted at 17:35:07 on January 9, 2016 · (Permalink)
Subscribe to the YouTube channel. Calculus will be one of the first topics I'll address, as I'll hinge on it to explain other stuff.
CCNezin · 1 points · Posted at 17:20:18 on January 9, 2016 · (Permalink)
As someone who often browses math and physics Wikipedia pages, I'm a big fan of your work. How do you create these awesome images and animations?
lucasvb · 1 points · Posted at 17:34:43 on January 9, 2016 · (Permalink)
Check this comment.
CCNezin · 1 points · Posted at 17:59:45 on January 9, 2016 · (Permalink)
Thanks :)
[deleted] · 1 points · Posted at 17:21:18 on January 9, 2016 · (Permalink)
That really was an excellent visualization. Thank you.
Namhaid · 1 points · Posted at 17:22:05 on January 9, 2016 · (Permalink)
I just did this, and realized that you're the author of so many gifs that have helped me. My hs math teacher hated me and kept me from learning, and so I only recently got back into the subject when I began exploring coding, and I can't tell you how awesome many of these visualizations were for my progress. Keep it up.
lmaodude · 1 points · Posted at 17:22:13 on January 9, 2016 · (Permalink)
Pretty rad work g
[deleted] · 1 points · Posted at 17:23:17 on January 9, 2016 · (Permalink)
You made that gif?! And you have a YouTube channel?!
Subscribed.
droads86 · 1 points · Posted at 17:24:51 on January 9, 2016 · (Permalink)
Visualizations such as yours would go a long way in school for a lot of people. Too many students don't understand the basic principles then give up on any of the follow up content. These gifs and images would go a long way.
PartizanParticleCook · 120 points · Posted at 09:31:47 on January 9, 2016 · (Permalink)
Better late than never
[deleted] · 16 points · Posted at 10:22:16 on January 9, 2016 · (Permalink)
I still keep the hope.
venuswasaflytrap · 88 points · Posted at 12:16:03 on January 9, 2016 · (Permalink)
Better Nate than lever
Jaywebbs90 · 39 points · Posted at 12:57:52 on January 9, 2016 · (Permalink)
Oh fuck you. All that time for just a stupid pun. I swear to god I will never forgive that site or anyone who reminds me of it.
[deleted] · 11 points · Posted at 13:06:54 on January 9, 2016 · (Permalink)*
[deleted]
ehrwien · 4 points · Posted at 13:21:37 on January 9, 2016 · (Permalink)
www.natethesnake.com
[deleted] · 2 points · Posted at 13:24:39 on January 9, 2016 · (Permalink)
[deleted]
CaptainCocoabean · 3 points · Posted at 16:41:43 on January 9, 2016 · (Permalink)
The other website adds another layer to the joke, though, if you scroll past the end.
raznog · 5 points · Posted at 13:07:37 on January 9, 2016 · (Permalink)
Oh come on it was a fun story.
Fudge89 · 1 points · Posted at 20:02:56 on January 9, 2016 · (Permalink)
I love it. I wasn't even mad after reading it. I just have to be sure to pass it on as much as I can to compensate for how much I cried later on that night. I divorced my wife and moved back in with my parents after I read it. I'm doing fine.
VisionsOfUranus · 6 points · Posted at 13:13:59 on January 9, 2016 · (Permalink)
And if you're not American, the joke doesn't even work, because you pronounce lever as lee-ver.
larae_is_bored · 4 points · Posted at 14:08:43 on January 9, 2016 · (Permalink)
One of the perks of FREEDOM!
JoeHook · -1 points · Posted at 13:49:44 on January 9, 2016 · (Permalink)
Better neat than lever.
Works for "lee-ver" pronouncers.
VisionsOfUranus · 3 points · Posted at 14:44:17 on January 9, 2016 · (Permalink)
No it doesn't.
JoeHook · 2 points · Posted at 15:41:59 on January 9, 2016 · (Permalink)
It does if you're Scottish, Kiwi or Aussie.
willrapfornepats · 1 points · Posted at 18:05:23 on January 9, 2016 · (Permalink)
When I worked as a camp counselor over the summer, I told this joke to each new group of campers. Some loved it. Some hated it
Edit: 1 word
tharkimaa · 11 points · Posted at 13:06:48 on January 9, 2016 · (Permalink)
You just gave away the ending to one of the most elaborate jokes in the world.
anomalous_cowherd · -5 points · Posted at 13:47:44 on January 9, 2016 · (Permalink)*
And you just lost the game.
Edit: just for this one, I relish your downvotes. Thank you all sincerely, it warms my heart!
AveryAWhiteMale · 1 points · Posted at 15:26:19 on January 9, 2016 · (Permalink)
I can never explain the joke to anyone because it's so long so the punchline just sits around in my head floating around.
Cheesemacher · 127 points · Posted at 11:25:34 on January 9, 2016 · (Permalink)
When I saw this for the first time the relationship between a unit circle and the graph of the sine function finally clicked for me.
samsg1 · 41 points · Posted at 11:50:31 on January 9, 2016 · (Permalink)
Why did they not show this to us in school? Makes it so clear!!
SVEN_10 · 72 points · Posted at 12:15:11 on January 9, 2016 · (Permalink)
It's in the textbook. It's not moving though. Hoping we'll have math books with animations soon.
[deleted] · 2 points · Posted at 12:46:22 on January 9, 2016 · (Permalink)
[removed]
[deleted] · -1 points · Posted at 13:07:50 on January 9, 2016 · (Permalink)
[removed]
[deleted] · 2 points · Posted at 13:11:29 on January 9, 2016 · (Permalink)
[removed]
chrisd93 · 1 points · Posted at 17:34:31 on January 9, 2016 · (Permalink)
I mean they do have projectors lol
GlyphGryph · 1 points · Posted at 14:15:19 on January 9, 2016 · (Permalink)
It was certainly never in any of my textbooks as a kid.
FuckingaFuck · 36 points · Posted at 13:03:42 on January 9, 2016 · (Permalink)
As a high school precalculus teacher, I show this GIF to my students a few times a year.
from_dust · 12 points · Posted at 14:27:51 on January 9, 2016 · (Permalink)
Keep up the good fight. I did well with geometry but the "Greek" math never worked well for me, I think mostly because I couldn't understand what exactly it was accomplishing. Just plugging stuff into formulas isn't learning. Anyway, things like this would have made a huge difference for me in the classroom. Don't give up on kids like me! We are smart I swear!
Noncomment · 2 points · Posted at 19:00:56 on January 9, 2016 · (Permalink)
That's ironic, because Greek mathematics used visual explanations and reasoning a lot. My school just had us memorize formulas, it was awful.
PM_me_ur_Dinosaur · 1 points · Posted at 14:10:33 on January 9, 2016 · (Permalink)
I could have really used this in algebra and FST too.
uber1337h4xx0r · 1 points · Posted at 21:14:35 on January 9, 2016 · (Permalink)
And I bet they still don't pay attention. Source: used to be a high school student.
Rather_Unfortunate · 1 points · Posted at 00:19:54 on January 10, 2016 · (Permalink)
In A-Level physics in the UK, I remember they used this quite heavily in the context of phasors for light or sound waves. It demonstrated constructive interference, too.
[deleted] · 1 points · Posted at 23:30:13 on January 9, 2016 · (Permalink)
Except this is wrong... The x axis shouldn't be labeled x. It should be theta. And even better, theta should be defined.
classicsat · 0 points · Posted at 13:52:02 on January 9, 2016 · (Permalink)
Gif,no. A real machine brought that to my reality.
[deleted] · 48 points · Posted at 15:23:53 on January 9, 2016 · (Permalink)
...how do you not understand that in your 3rd year of engineering school?
Zjurc · 7 points · Posted at 20:47:18 on January 9, 2016 · (Permalink)
I'm surprised he made it this far without hearing anyone at least mention this relation - then again, learning and understanding are two completely different things
I_like_to_eat_fish · 2 points · Posted at 06:31:48 on January 10, 2016 · (Permalink)
He's flunking out soon, is going to a very low ranked engineering school, or is lying. He basically just said, "Oh, I just realized that pi is the ratio of the circumference to the diameter". I'm sorry but there's just no way.
[deleted] · 1 points · Posted at 15:40:34 on January 10, 2016 · (Permalink)
That was my impression as well, honestly
DieFledermouse · 2 points · Posted at 22:08:59 on January 9, 2016 · (Permalink)
The vast majority of science/engineering/CS grads memorize and plug&chug equations for tests. Then they do a core dump to be fresh for the next semester. Actually understanding is tough. I knew straight A students who didn't understand a damn thing.
[deleted] · 1 points · Posted at 04:12:54 on January 10, 2016 · (Permalink)
I am a (former) straight A student with a masters in engineering. Yeah I can memorize the process behind Cauchy's Integral Theorems and know how to use them to solve complex differential equations... but understanding WHY they work is still kind of a mystery.
But like.. radians? This is like really really basic stuff. I understood this in like 10th grade
AppearMissing · 72 points · Posted at 11:00:20 on January 9, 2016 · (Permalink)
Graduated from engineering school 2 years ago, it just clicked.
mlkelty · 112 points · Posted at 12:13:17 on January 9, 2016 · (Permalink)
I watched the gif. Now I'm an engineer.
Choo choo!
GoTaW · 49 points · Posted at 14:37:52 on January 9, 2016 · (Permalink)
What do you engineer and how can I avoid interacting with it?
uber1337h4xx0r · 5 points · Posted at 21:15:21 on January 9, 2016 · (Permalink)
Social, give me your email password and username and I'll explain it.
ProudFeminist1 · 0 points · Posted at 11:31:20 on January 9, 2016 · (Permalink)
How much do you use all the math that you learned? Now in my first year and wondering if I can slack my way through it like I did high school.
laseralex · 56 points · Posted at 11:41:19 on January 9, 2016 · (Permalink)
42 year old EE here. I use the math basically never. But I use the concepts every fucking day.
I'm fairly successful, and try to surround myself by other successful people. I've had lots of conversations where we say " I wish I had paid more attention in my ______ class". Not once have I heard an associate say they felt they over-learned a subject.
There is no way you will use everything you learn in school. But you won't know for another 10 years which topics will turn out to be useful. So study your ass off, and do the best you can in every class.
You are setting your career for the next 40 years. Set yourself up for success!
Kingy_who · 5 points · Posted at 11:53:28 on January 9, 2016 · (Permalink)
The thing is that "I wish I spent more time doing x" does mean that they wish they spent less time doing something else.
Sometimes you might find that the rocketry club (for example) is more interesting than your degree and you are doing your degree so you can keep doing that. In university sometimes the degree isn't the important bit.
Bibbster94 · 5 points · Posted at 12:27:13 on January 9, 2016 · (Permalink)
Studying females at the bar
TheFatalBellman · 3 points · Posted at 13:13:59 on January 9, 2016 · (Permalink)
Don't think much time would have been spent on that
ProudFeminist1 · 6 points · Posted at 13:51:08 on January 9, 2016 · (Permalink)
We have 4 females and three of those don't really look like females.
from_dust · 1 points · Posted at 14:29:24 on January 9, 2016 · (Permalink)
I would argue that usually the degree isn't the important bit. It's everything surrounding the university experience and how that shapes you as a person that is the most defining portion.
choomguy · 1 points · Posted at 13:09:42 on January 9, 2016 · (Permalink)
That's great advice, and also learn as much as you can outside of your field. I roomed with a bunch of engineers in college, and work with them all the time in my career. It takes them a few years beyond college to realize they are not the smartest people in the world, and they they don't know everything. I'm getting a kick out of some of these responses.
ProudFeminist1 · 0 points · Posted at 11:58:18 on January 9, 2016 · (Permalink)
Yeah your right, but it helps that I find everything except math very interesting.
Obvious0ne · 1 points · Posted at 13:03:28 on January 9, 2016 · (Permalink)
How do you feel about spelling?
ProudFeminist1 · 1 points · Posted at 13:14:28 on January 9, 2016 · (Permalink)
Both my dutch, german, french and english spelling is horrible bit good enough.
tusksrus · 2 points · Posted at 13:36:18 on January 9, 2016 · (Permalink)
Both of those four?
ProudFeminist1 · 1 points · Posted at 13:39:07 on January 9, 2016 · (Permalink)
Boht off these for
ahappypoop · 0 points · Posted at 13:04:04 on January 9, 2016 · (Permalink)
Everything except for math and grammar I see.
2edgy4mi · 19 points · Posted at 11:38:56 on January 9, 2016 · (Permalink)
Bahahha Don't do that. Get them A in the easy classes.
To be fair tho most of the math is just what you can apply to physics of a moving or stationary body.
Integration is not the crazy things you see in calc, but still necessary for the courses.
Don't slack, the A now will help counteract a possible C (although i know someone with straight A's in civil 💀)
OTHER_ACCOUNT_STUFFS · 2 points · Posted at 13:36:19 on January 9, 2016 · (Permalink)
Civil is the easiest one though.
ProudFeminist1 · 2 points · Posted at 13:53:05 on January 9, 2016 · (Permalink)
My friend in civil is laughing so hard at his classes. The physics is almost not existing and if you can learn good from books you don't have to spend a lot of time learning.
OTHER_ACCOUNT_STUFFS · 2 points · Posted at 14:14:21 on January 9, 2016 · (Permalink)
They are the butt off many jokes in engineering school. Not quite business major level joking though.
uber1337h4xx0r · 1 points · Posted at 21:17:45 on January 9, 2016 · (Permalink)
I mean, they and industrial (lol) are barely even engineering.
Then again... Neither are we software engineers. :(
2edgy4mi · 1 points · Posted at 14:25:24 on January 9, 2016 · (Permalink)
Good to know 👌
ProudFeminist1 · -6 points · Posted at 11:56:50 on January 9, 2016 · (Permalink)
Hmm shame, but yeah if you say it's necessery haha. It's still quite easy for me but I really do need to my homework because I now do it just the week before the test.
helgaofthenorth · 5 points · Posted at 12:18:09 on January 9, 2016 · (Permalink)
Learn good study habits. Please. If you're going to do this you're going to need them, and if you breezed through high school you probably never did.
ProudFeminist1 · -5 points · Posted at 12:22:03 on January 9, 2016 · (Permalink)
yeah I know that I need to get good study habits and it's not like I don't do anything but I'm just saying that I'm having it quite easy at the moment, yes I have to do something for it but it's not overtaking my life or something.
[deleted] · 1 points · Posted at 12:57:56 on January 9, 2016 · (Permalink)
Don't slack: Use this to your advantage. Study that shit and nail it. Get them A's.
Enthused_Llama · 1 points · Posted at 14:41:30 on January 9, 2016 · (Permalink)
It will, get your shit together now.
Source: I have to go work on my rocket now.
2edgy4mi · 1 points · Posted at 12:58:33 on January 9, 2016 · (Permalink)
Sucks, my professors collected that shit weekly, kinds grateful for that lol.
If you have any trouble I discovered patrickJMT a bit too late but he helped tremendously, highly recommend his channel
ProudFeminist1 · 1 points · Posted at 13:15:59 on January 9, 2016 · (Permalink)
You should be grateful, it forces good habits. I'll look him up thanks!
[deleted] · 6 points · Posted at 12:56:32 on January 9, 2016 · (Permalink)*
This is the kind of attitude that makes people not want to hire you.
If you want to be an engineer, you have to want to be an engineer, and that comes with using math.
Edit: It was advice. Being a dick about it is only going to make your situation worse.
ProudFeminist1 · -2 points · Posted at 13:21:22 on January 9, 2016 · (Permalink)
Luckily you aren't hiring.
Roleorolo · 1 points · Posted at 12:30:22 on January 9, 2016 · (Permalink)
in my 3rd year doing Engineering. If you can learn eigenvalues + eigenvectores inside out, such that you'll never forget it. They pop up all over the place :). Some bits of the math you won't use (the more abstract stuff), but lots of it you will. Unfortunately it's hard to know which bits are and aren't relevent (some bits are more relevent to those who will study pure maths, and some more relevent to engineering/physics).
uncle_shaky · 1 points · Posted at 14:05:56 on January 9, 2016 · (Permalink)
I recently used calculus at my job, 24 years after I finished my undergrad EE degree. I'm a SW engineer now and was working on an optimization for an extremely high precision positioning system. But it was only basic differentiation. I have yet to use integration, but I have some colleagues whose job it is to do high-level math stuff like modeling random processes.
So ... I concur with laseralex. You never know what you'll need at some point down the line. If I had slacked during my calc classes I most likely would not have figured out the issue I mentioned above.
ProudFeminist1 · 1 points · Posted at 14:37:58 on January 9, 2016 · (Permalink)
Do you mean solidworks with sw? If so can you really trust the calculations solidworks makes? To a noob engineer like me it seems impossible that it can calculate a simulation the way it will behave in the real world.
uncle_shaky · 1 points · Posted at 15:07:55 on January 9, 2016 · (Permalink)
Nope no solidworks going on for me. A bunch of much-smarter-than-me types came up with a characteristic function that described the position error based on a few other parameters. I had to figure out how to use this in an application.
I too am amazed with some of the SW tools available. The ones that I see used "in the shop" do a pretty good job of approximating sensor signal traces and such, but of course the real-world signals aren't quite as "neat".
Enthused_Llama · 1 points · Posted at 14:39:04 on January 9, 2016 · (Permalink)
Don't, that's the dumbest idea ever. You're going to want to get internships and/or co-ops so you can have job experience before you graduate.
Exactly zero recruiters will be impressed with 'well some guy on reddit said I didn't really need it so I got a C because fuck it.'
AppearMissing · 1 points · Posted at 16:37:33 on January 9, 2016 · (Permalink)
I work in procurement so not much.
[deleted] · 0 points · Posted at 12:55:59 on January 9, 2016 · (Permalink)
Holy fuck, five years ago for me. Mind = blown.
[deleted] · 2 points · Posted at 16:03:44 on January 9, 2016 · (Permalink)*
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[deleted] · 1 points · Posted at 17:09:10 on January 9, 2016 · (Permalink)
Well I knew a circle circumference was 2* pi* r I just never thought about it like a radius was a radian.
[deleted] · 2 points · Posted at 17:47:05 on January 9, 2016 · (Permalink)*
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[deleted] · 0 points · Posted at 18:36:42 on January 9, 2016 · (Permalink)
fuck i dunno =D
Tinie_Snipah · 94 points · Posted at 11:35:54 on January 9, 2016 · (Permalink)
I don't mean to be rude but how on earth did you get 3 years into any relevant engineering field before being able use radians and understand them. We had to learn them and be tested on full understanding a year before even applying to university. Crazy
TyeDyeShirtKid · 71 points · Posted at 11:56:05 on January 9, 2016 · (Permalink)*
I don't think s/he meant s/he didn't know how to use radians in mathematics. The gif visualizes the "length" of one radian. I didn't actually make the connection until just now either. I am also in my third year of my engineering education, and I've been plenty successful in my use of radians in my math courses regardless.
EDIT: For the people who are telling me I have no idea what I'm doing in math, it's fairly clear that this entire string of comments is relating to the ORIGIN of the radian not how they're actually used. But please continue to tell me how I don't actually understand math and am somehow just breezing through my university courses without actually knowing my shit.
EDIT 2: since I'm still getting comments telling me about when they learned about radians (hint: I don't care) what I meant when I said it clicked for me was that I hadn't thought about the arc length of a radian since I learned it and since must have forgotten the connection. That's all... now please stop telling me about how good you are at geometry.
mrgonzalez · 7 points · Posted at 14:46:35 on January 9, 2016 · (Permalink)
It is kind of surprising because it ties in quite neatly with what pi is in the first place.
Denziloe · 46 points · Posted at 14:43:43 on January 9, 2016 · (Permalink)
If you didn't know or understand the definition of one radian then you really didn't know what radians were, you just learned by rote how to use them in certain contexts.
feed_me_haribo · 13 points · Posted at 16:51:40 on January 9, 2016 · (Permalink)
It's like in pre-calc physics, where you're presented a whole bunch of projectile equations that you essentially have to memorize because you don't know calculus. A waste of time IMO. What's the point in teaching memorization? Just wait til you have the proper framework to understand more thoroughly and it becomes much easier.
LordOfTheGiraffes · 2 points · Posted at 00:19:51 on January 10, 2016 · (Permalink)
Seriously. Calc should be a prerequisite for any physics course.
Rebmes · 1 points · Posted at 17:43:05 on January 9, 2016 · (Permalink)
I would say that spending a year using those formulae without calc was absolutely beneficial. I wasn't ready to understand the calculus but I got all of the conceptual stuff down.
feed_me_haribo · 4 points · Posted at 18:43:22 on January 9, 2016 · (Permalink)
I'm not sure how you can really conceptually understand force =ma, momentum, etc. without understanding the mathematical relationships between distance, velocity and acceleration and force and momentum. Sure, you can give something a force it accelerates, but to start calculating motions means you are either blinding using equations from a book or you know calculus. There's a reason the man behind F=ma was also one of a couple behind the formation of calculus.
Rebmes · 2 points · Posted at 20:05:58 on January 9, 2016 · (Permalink)
I'm not talking about necessarily understanding conceptually the equations, I mean understanding what acceleration or velocity is, how basic vectoral operations work, etc. We tended to not focus on the math as much as reasoning and understanding very basic kinematics and electromagnetism. Of course knowing the calculus behind everything would make it easier and a bit more clear, I'm not denying that.
LordOfTheGiraffes · 1 points · Posted at 00:18:21 on January 10, 2016 · (Permalink)
Calculus really isn't that hard if taught well. I remember when I first learned it so many of my questions about the world were answered and I wondered why they didn't teach it to everyone (at least on a rudimentary level).
Rebmes · 2 points · Posted at 00:35:58 on January 10, 2016 · (Permalink)
That's true but there really isn't enough time anymore (at least for AP Physics I) to teach the calculus and the physics when most of the students are only in precalculus. What you're advocating certainly makes more sense if it's all or mostly seniors in the class already have a good grip on precalculus and are learning calculus simultaneously but that's not the case anymore in AP Physics I. In AP Physics C that is the case so the College Board feels more comfortable introducing calculus. Is this the right way to go? I really don't know, but I see why they did it. I was the first year to take the new Physics I Algebra-Based course and it seemed that we were less crunched for time and able to go into greater depth when talking about a lot of things even if we were unable to do that math.
LordOfTheGiraffes · 1 points · Posted at 00:47:33 on January 10, 2016 · (Permalink)
Well, that still seems better than my high school experience. It was a while ago, but there were only a few AP courses and none were in the sciences. I'm actually far enough removed from high school that I probably have no idea what's going on anymore, haha.
trackerFF · 3 points · Posted at 16:29:07 on January 9, 2016 · (Permalink)
Which unfortunately is how you can get through calc 1-3, linear algebra and diff. equations. I mean, they're supposed to be the building blocks for higher math, but only if you actually understand the material. Getting through without much understanding is entirely possible, unless your professor is very, very proof oriented.
TyeDyeShirtKid · 1 points · Posted at 21:15:57 on January 9, 2016 · (Permalink)
Please continue to tell me what I know and don't know... perhaps check out /r/iamverysmart while you're at it.
[deleted] · 0 points · Posted at 15:58:00 on January 10, 2016 · (Permalink)
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[deleted] · 1 points · Posted at 19:14:35 on January 10, 2016 · (Permalink)
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Denziloe · 0 points · Posted at 19:30:11 on January 10, 2016 · (Permalink)
The gif just animates the definition of a radian. If it surprised you then you didn't know the definition of a radian.
TyeDyeShirtKid · 1 points · Posted at 19:38:31 on January 10, 2016 · (Permalink)
I didn't say I didn't understand the entire thing. You're making assumptions about what part I meant I said "clicked" when I watched it.
But I don't need to justify myself to you. I'm doing quite well at a prominent American university and have no desire to continue justifying my math skills to you.
Denziloe · 1 points · Posted at 19:50:05 on January 10, 2016 · (Permalink)
Okay, so you didn't understand why there were pi of them in a half turn. Good luck at uni.
TyeDyeShirtKid · 1 points · Posted at 19:56:16 on January 10, 2016 · (Permalink)
I know exactly why there are pi radians in half a circle. And I'll enjoy my six figure salary straight out of school ;)
Denziloe · 0 points · Posted at 20:05:24 on January 10, 2016 · (Permalink)
But your original comment is explicit about the fact that you didn't understand how one radian is defined and how it relates to arc length. And that you simply knew how to use them in practice. All my comment says is stuff that you later edited into your own comment. Stop being a manbaby, it's really tedious.
TyeDyeShirtKid · 1 points · Posted at 20:22:24 on January 10, 2016 · (Permalink)
Oh great radian overlord I bow at the feet of your wisdom.
Is it really that important for you to tell me over and over that I don't know what radians are? Someone needs a hobby.
Concise_Pirate · 0 points · Posted at 21:56:10 on January 10, 2016 · (Permalink)
rule 1 please.
Zerksues · 1 points · Posted at 16:00:04 on January 9, 2016 · (Permalink)
That is really surprising. Because I learnt about radians in second year of high school and this gif is basically the physical interpretation of the mathematical definition. You divide the circle into "2π parts" each of which subtends an equal angle (1 rad) at the centre.
TyeDyeShirtKid · 1 points · Posted at 21:15:20 on January 9, 2016 · (Permalink)
I don't think you understand what he (and I) are saying. We know that a circle is 2pi radians and we can use them in math, it's more about the origin of the radian than anything else.
Zerksues · 0 points · Posted at 03:56:46 on January 10, 2016 · (Permalink)
And I'm saying that I (and most of my class) understood the "origin" before being able to use radians as well as degrees. A lot of things fit beautifully together. The circumference is 2πr. π is the ratio of of the circumference to the diameter (same as the previous, I know). Radians are called RADIans because its the angle subtended by a portion of circumference equal to the RADIus. I'm saying that all these things (for me, at least) clicked the moment I was introduced to radians.
TyeDyeShirtKid · 1 points · Posted at 06:39:32 on January 10, 2016 · (Permalink)
Well congratulations, you're better at radian history than me, is that what you needed to hear? I probably was told that at some point and just let it slip away after it became irrelevant; because let's face it, as engineering students it's much more important to know how to use math than to understand its definitions. The theory is for the mathematicians to sort out.
LordOfTheGiraffes · 1 points · Posted at 00:28:27 on January 10, 2016 · (Permalink)
I felt the same way. Radians were introduced to me by this definition, and I'm surprised that it's done any other way.
Also TIL "learnt" is a word.
WeWantBootsy · 1 points · Posted at 16:11:13 on January 9, 2016 · (Permalink)
That's the problem with engineering school. It throws a ton of concepts at you without explaining any of them and then rushes you through all of them so everything just becomes words on a page. I used to hold math tutoring for lower class men and I'd draw this stuff out. It only clicked for me then.
LordOfTheGiraffes · 1 points · Posted at 00:31:21 on January 10, 2016 · (Permalink)
That's a really broad generalization. When I took engineering in college the curriculum went deeply into the theory and origins of concepts. Professors regularly took the time to show derivations in lectures (or at least tell you where to find them).
WeWantBootsy · 1 points · Posted at 05:36:20 on January 10, 2016 · (Permalink)
Fair enough. I can only speak for my time at a highly rated engineering school, but our professors were so concerned with their research, the classes were an afterthought for them and they regularly were not available during office hours. They would just throw concept after concept out in class with no explanation of where it came from. We used to joke electricity was just a magic thing in a box from a wizard because we barely understood the concepts.
[deleted] · 1 points · Posted at 19:14:02 on January 9, 2016 · (Permalink)
One radian is an angle not a length.
TyeDyeShirtKid · 1 points · Posted at 21:14:06 on January 9, 2016 · (Permalink)
Yes I understand how radians are used, but if you watch the gif you clearly see an arc length that supplies us with that angle.
cbmuser · 1 points · Posted at 01:22:55 on January 10, 2016 · (Permalink)
I learnt that in 6th or 7th grad here in Germany ;).
TyeDyeShirtKid · 1 points · Posted at 02:40:45 on January 10, 2016 · (Permalink)
Congrats, I'm doing quite well without knowing the origin of radians thanks ;)
[deleted] · 1 points · Posted at 05:28:19 on January 10, 2016 · (Permalink)
I'm just curious - how was the concept of a radian introduced to you then? Did they just say "here's a new unit we're using now" and leave it at that, no questions asked? Or pi? Surely someone at some point explained that it wasn't just a random assortment of numbers?
I'm just not sure how the radian gets brought up without an explanation of what it is in relation to a circle.
TyeDyeShirtKid · 1 points · Posted at 06:40:22 on January 10, 2016 · (Permalink)
I have no idea, it's been nearly a decade since I first heard the word radian. I was probably told what they come from and let it slip away because it's irrelevant to your ability to use them in mathematics.
Tinie_Snipah · -12 points · Posted at 12:15:50 on January 9, 2016 · (Permalink)
Well then you must both be taught pretty poorly if you are only told how to use them and not what they are.
That's no way to learn maths
Jora_ · 3 points · Posted at 13:00:27 on January 9, 2016 · (Permalink)
Which is probably fine because s/he is studying engineering.
I would argue that an engineers ability to assess stress, fatigue, shear etc. of materials does not depend on having a fundamental understanding of the chemical interactions of that material at an atomic scale. Sure it might help, but it is not essential and certainly not indicative of poor teaching.
Similarly the theory behind radians is not an essential prerequisite to using them as a tool in engineering.
MorgenGry · 2 points · Posted at 13:10:07 on January 9, 2016 · (Permalink)
Same with biology, I use math to model population dynamics, I use the logit tranformation to keep changes to a survival rate between 0 and 1 as a function of shocks, I have no idea how exactly it does that but hey it works, and the math guys say it's legit.
LordOfTheGiraffes · 1 points · Posted at 00:35:09 on January 10, 2016 · (Permalink)
As an engineer I beg to differ. An engineer might be able to get by blindly using sets of equations as tools, but that's just asking for problems. IMO a firm understanding of how and why the math works is critical to understanding how to apply it.
Jora_ · 1 points · Posted at 02:02:53 on January 10, 2016 · (Permalink)
I'm an engineer myself. Day-to-day, I do not need to know the fundamental principle behind every mathematical tool I use, in the same way I don't need to know the source code for the programs I use.
Engineering is about practical application of theory, not necessarily theory itself.
LordOfTheGiraffes · 1 points · Posted at 02:36:44 on January 10, 2016 · (Permalink)
I suppose it depends on the type of engineering. I work in a field where fundamental understanding is often critical. I also frequently do need to the know the source code for the programs I use, because I often have to write them myself.
I view it as a requirement in my area, and honestly can't think of any others where it wouldn't be at least a distinct advantage.
Tinie_Snipah · 1 points · Posted at 19:14:01 on January 10, 2016 · (Permalink)
Then it isn't relevant was only put in to make them sound smarter. If you don't need this stuff in your life then why are you mentioning it? It's like saying "Well I graduated from law school last year but only now do I understand the sine rule"
It just reads as "I know this is going to sound stupid but honestly I'm a really smart person; look, here's proof!"
If it's not relevant then don't say it.
jermdizzle · 1 points · Posted at 15:25:33 on January 9, 2016 · (Permalink)
In an ideal world you're right. No one explained what radians were to me until it randomly came up in my calc 2 class a few semesters ago. No one every bothered. I memorized the unit circle but no one taught me that 1 radian was just the arc length of the radius length.
uReallyShouldTrustMe · 0 points · Posted at 12:45:30 on January 9, 2016 · (Permalink)
Some people understand some concepts of math better than others. I agree though, and the US is actively trying to change this.
[deleted] · -1 points · Posted at 12:59:49 on January 9, 2016 · (Permalink)
I have to agree... this is a basic concept I learned in middle school. It really is something that is easy to visualize and could give people a better insight in how the principle works, so I don't understand why some education systems or schools don't employ such tricks.
Tinie_Snipah · 2 points · Posted at 19:11:38 on January 10, 2016 · (Permalink)
I'm glad you agree, maths should be learnt by understanding how things happen. That's why maths lessons are built up over years and not taught at complex levels at a very early age. Because it gives you knowledge of how the stuff you learn one year will influence you the next.
TyeDyeShirtKid · 0 points · Posted at 21:16:51 on January 9, 2016 · (Permalink)
You know nothing about what I know and don't know, unless of course you are gifted with telepathy through the internet as well as your glorious 'maths' education.
ByronicWolf · 7 points · Posted at 12:31:53 on January 9, 2016 · (Permalink)
It's the difference between understanding and comprehension. He probably understands radians and how they work fairly well. But perhaps the visualization helped it click in his brain, and now he comprehends the concept.
Denziloe · 0 points · Posted at 14:44:56 on January 9, 2016 · (Permalink)
I don't think there's much of a difference between understanding and comprehension.
I'd say he knows the definition, but doesn't fully understand/comprehend it.
ByronicWolf · 1 points · Posted at 15:35:20 on January 9, 2016 · (Permalink)
English is not my primary language, so I suppose I may be wrong. What I've been taught is that comprehension, due to its Latin root, has the meaning of grasping/encompassing. Thus, to comprehend is to fully internalize a concept, compared to the perhaps shallower knowledge implied by understanding.
Tinie_Snipah · -4 points · Posted at 12:32:28 on January 9, 2016 · (Permalink)
That just seems like poor teaching then
antiproton · 2 points · Posted at 12:56:54 on January 9, 2016 · (Permalink)
It's not even remotely necessary to understand the origin of the raidan to use them in calculations. More to the point, understanding this concept doesn't get you anything.
You probably learned how to use the fundamental theorem of algebra a long time ago.... can you prove it?
Gripey · 1 points · Posted at 14:51:18 on January 9, 2016 · (Permalink)
I reluctantly agree, but I would add that I only understood pi was "just" the ratio of the diameter needed to go around the perimeter of any circle in my fifities. Lights went on all over my maths history. It gives you the confidence to work things out instead of just remembering. I used to think pi was a magic number...
Tinie_Snipah · 1 points · Posted at 19:10:19 on January 10, 2016 · (Permalink)
This isn't anything even close to a proof, it is just how something works. It is a poor way to teach maths what happens instead of how. Understanding how is the key to understanding what, and without knowing how it's very hard to accurately and efficiently use the what.
antiproton · 1 points · Posted at 21:33:53 on January 10, 2016 · (Permalink)
You could spend all your time exploring the origins of every single concept you need to use in math. And then you'd get literally nothing done.
Radians is just a convenient convention. You are trying to claim this obfuscates some deeper insight and that is just false.
Tinie_Snipah · 1 points · Posted at 00:11:41 on January 11, 2016 · (Permalink)
Well technically you'd be a mathematician and might further the knowledge of others, but that's not the point.
No it's a bad way of teaching and a bad way of learning. It sets bad standards
MyButtt · 0 points · Posted at 12:47:42 on January 9, 2016 · (Permalink)
It's not like everybody wants to or is going to be a great success in math, science or engineering like you.
[deleted] · -1 points · Posted at 13:00:56 on January 9, 2016 · (Permalink)
He never suggested anything like that.
It is poor teaching, especially since it's such an easy concept. I learned this in middle school and understand it to this day and I don't even study anything remotely similar to math.
MyButtt · 0 points · Posted at 13:13:20 on January 9, 2016 · (Permalink)
And what I'm saying is that he would know since he's so very smart. Look, different people learn things differently and for some even the most succinct explanations and diagrams might not get the concept to click in the way a 30 second gif will.
[deleted] · 0 points · Posted at 13:43:37 on January 9, 2016 · (Permalink)
Perhaps. Does that mean we shouldn't try to include frame-by-frame like diagrams in textbooks? Because with a few frames, the concept will become clear even without animation.
MyButtt · 0 points · Posted at 13:47:49 on January 9, 2016 · (Permalink)
Nobody is suggesting that or anything close to that.
For most people. For some it will take an animation and others maybe something else.
RedSpikeyThing · 2 points · Posted at 15:38:38 on January 9, 2016 · (Permalink)
There are ways out. Convert to degrees and carry on
Tinie_Snipah · 1 points · Posted at 19:17:17 on January 10, 2016 · (Permalink)
And that's an extra step which adds more confusion and chance for mistakes. Not worth it. Radians are better for trig functions
Fargraven · 2 points · Posted at 16:39:31 on January 9, 2016 · (Permalink)
That's what I was thinking too. I'm a junior in high school and learned/understood them this week...
fucky_fucky · 1 points · Posted at 15:21:38 on January 9, 2016 · (Permalink)
You can use something without fully understanding it.
Tinie_Snipah · 1 points · Posted at 19:14:38 on January 10, 2016 · (Permalink)
You can but it's not a good way of learning, especially in maths. You can fix a car without doing any mechanical qualifications and you can fly a plane without a license, but good luck trying to get a job in a relevant field without being able to show you have the understanding
fucky_fucky · 0 points · Posted at 19:34:49 on January 10, 2016 · (Permalink)
Ok.
Doomur17 · 1 points · Posted at 03:04:35 on January 10, 2016 · (Permalink)
No I knew how to use them I just didn't get where they came from
Tinie_Snipah · 1 points · Posted at 19:18:48 on January 10, 2016 · (Permalink)
As I said, poor teaching
Aurora_Fatalis · 22 points · Posted at 12:39:36 on January 9, 2016 · (Permalink)
Don't worry, I once had a university physics student ask me what a sine function was. That person is now sleeping with my ex.
Denziloe · 49 points · Posted at 14:48:39 on January 9, 2016 · (Permalink)
I GUESS THAT MAKES IT A SIN OF X HA HA HA
Aurora_Fatalis · 4 points · Posted at 14:50:08 on January 9, 2016 · (Permalink)
Turns out it was just an imaginary exp.
glorkcakes · 24 points · Posted at 12:55:37 on January 9, 2016 · (Permalink)
whos the real winner here
[deleted] · 0 points · Posted at 21:30:52 on January 9, 2016 · (Permalink)
Ken, because he spammmed shoryuken like a cheating bitch.
Longroadtonowhere_ · 1 points · Posted at 20:59:08 on January 9, 2016 · (Permalink)
Well, it something to do with triangles, but also circles and pi.
Hashtag_life · 1 points · Posted at 18:27:46 on January 9, 2016 · (Permalink)
Are his grades between 1 and -1?
[deleted] · -4 points · Posted at 13:39:11 on January 9, 2016 · (Permalink)
A student asked you a question? God, what a jerk they must have been. Your attitude is bad.
Mitchhhhhh · 3 points · Posted at 15:43:41 on January 9, 2016 · (Permalink)
Mate, 2πr...
RealSarcasmBot · 2 points · Posted at 13:10:38 on January 9, 2016 · (Permalink)
I only understood these because rotating images in the framework i use is done in radians, not highschool, not university, nothing else made sense besides practical experimentation i guess.
theedgeways · 2 points · Posted at 14:28:06 on January 9, 2016 · (Permalink)
I know the feeling. Maths didn't really click for me until I nearly finished my CS degree. Now, I love maths.
FILE_ID_DIZ · 2 points · Posted at 14:37:40 on January 9, 2016 · (Permalink)
Come on, dude, it's as easy as pi.
[deleted] · 2 points · Posted at 21:22:26 on January 9, 2016 · (Permalink)
Also in 3rd year of engineering school. Someone could have told me radian is called a radian because it's the length is the circle's radius. Is it that so hard? When I first had pre-calc (covers trig at my school) I was happy the professor showed a gif that described pi.
[deleted] · 1 points · Posted at 14:38:01 on January 9, 2016 · (Permalink)
Well, the circumference of a circle is pi times the diameter (D), or pi times 2r since 2r = D.
PandaLover42 · 1 points · Posted at 21:41:04 on January 9, 2016 · (Permalink)
Dude, for real, this is like a middle school/early high school-level concept...
Mezmorizor · 1 points · Posted at 04:24:13 on January 10, 2016 · (Permalink)
Which showed up exactly zero times in my middle school/high school career.
And I was on the calc BC track.
PandaLover42 · 1 points · Posted at 06:01:48 on January 10, 2016 · (Permalink)
What do you mean? How did you end up on the Calc BC track in high school without learning that circumference = 2r(pi) back in algebra or whatever?
Mezmorizor · 1 points · Posted at 16:50:45 on January 10, 2016 · (Permalink)
We learned that, but that's not where radians come from. Arc length only showed up formally in freshman geometry, and the word radian was not uttered until Junior year pre calc.
khajiitFTW · 1 points · Posted at 14:58:47 on January 9, 2016 · (Permalink)
You would be surprised how common that is. I remember it took me quite sometime to realize some simple relations trigonometric functions . . . to embarrassed to say what they are though!
jermdizzle · 1 points · Posted at 15:19:14 on January 9, 2016 · (Permalink)
I finally figured this out randomly in a calc 2 class last year.
jcam07 · 1 points · Posted at 15:19:44 on January 9, 2016 · (Permalink)
Graduated Civi Engineer and in my Masters in Structural Engineering and it just clicked too
ILikeMasterChief · 1 points · Posted at 15:28:37 on January 9, 2016 · (Permalink)
Radical!
toritxtornado · 1 points · Posted at 15:51:27 on January 9, 2016 · (Permalink)
I have a degree in math at a major university. It just clicked.
Eastvwest33 · 1 points · Posted at 16:04:12 on January 9, 2016 · (Permalink)
This is the math they should be teach kids...
SIrPsychoNotSexy · 1 points · Posted at 16:23:00 on January 9, 2016 · (Permalink)
When did you take trig??
varlogkern · 1 points · Posted at 16:42:17 on January 9, 2016 · (Permalink)
Let me guess, your teachers did a lot of "just accept it, that is how it is." I had a really good calc professor in college (Calc 1&2) who actually didn't hand waive anything. I always respected that he would show us as much as out level of math taken would allow.
Vandechoz · 1 points · Posted at 16:48:33 on January 9, 2016 · (Permalink)
I think it clicked for me once, late at night cramming for an exam. I lost it by morning and never quite got it back. :(
aadams9900 · 1 points · Posted at 16:55:13 on January 9, 2016 · (Permalink)
Half way through my 3rd year physics. It all makes sense now! I always thought pi was an arbitrary number!
Bashar_Al_Dat_Assad · 1 points · Posted at 16:56:41 on January 9, 2016 · (Permalink)
Jesus fuck dude.
stamz · 1 points · Posted at 16:57:48 on January 9, 2016 · (Permalink)*
No offense to you, but I'm genuinely curious how you're 3 years into an engineering program and you just now got this.
The unit circle is like calc 1 level stuff. Did you just memorize the patterns and methods without seeing how they're all related?
I mean, better late than never, but how did you pass the first few levels of calc without it?
WolfThawra · 1 points · Posted at 17:11:43 on January 9, 2016 · (Permalink)
Oh hey, fellow soul.
FUCK_VIDEOS · 1 points · Posted at 17:15:12 on January 9, 2016 · (Permalink)
how has it not clicked since like... high school?
Hypersensation · 1 points · Posted at 17:18:53 on January 9, 2016 · (Permalink)
This isn't something that clicked in high school math? I thought it was pretty instrumental to even pass the most basic questions of it?
[deleted] · 1 points · Posted at 17:28:11 on January 9, 2016 · (Permalink)
What engineering are you going for?
bitwaba · 1 points · Posted at 17:29:09 on January 9, 2016 · (Permalink)
I was a math major in college. It wasn't until I was about 26 that I realized a radian is the measure of the Arc Length drawn by that "radian" on a unit circle.
With a unit circle, your radius is 1. The circumference of that circle is 2 * pi * r = 2pi. Just to keep it simple, if you were to measure 90 degrees angle, the length of the arc on the unit circle would be 1/4th of that 2pi. So, (1/2)pi. Guess what the 90 degrees is in radians? Yep! (1/2)pi. Just for reference, the formula we used when all put together is (frational portion of circle you wish to travel around) * 2 * pi * r.
How is it useful? Say you're about to drive on a roundabout with radius 12 meters, and your exit is 7/16ths of the way around the circle. How what would your odometer measure your distance as when you get to the end of the roundabout? (7/12) * 2 * pi * 18 meters = 21*pi meters, or ~0.065 kilometers
When that clicked in my head, I felt like the universe had opened up to me... or at least 10th grade trigonometry.
[deleted] · 1 points · Posted at 17:29:41 on January 9, 2016 · (Permalink)
Literally me too lol
chrisd93 · 1 points · Posted at 17:33:26 on January 9, 2016 · (Permalink)
How did calc go for you lol?
Frezerburnfish · 1 points · Posted at 17:35:35 on January 9, 2016 · (Permalink)
Half way through my first pie it clicked.
number90901 · 1 points · Posted at 17:36:37 on January 9, 2016 · (Permalink)
How was everyone not taught this the first time radians were mentioned in 10th grade? It's such a core concept, I couldn't have gotten through HS math without it.
Introvertsaremyth · 1 points · Posted at 17:37:04 on January 9, 2016 · (Permalink)
Not an engineer but my son is in a Montessori school. When they taught the Pythagorean theorem they actually laid out a large right triangle on the floor and had the kid stack cubes along each side to form a square so they could physically see A2+B2 =C2. Mind blown, I just had to memorize the formula I never visualized it or understood it like that. Why isn't all math explained that way?!
Rebmes · 1 points · Posted at 17:41:03 on January 9, 2016 · (Permalink)
Halfway through AP Calc. Just clicked for me too.
Arusht · 1 points · Posted at 17:49:20 on January 9, 2016 · (Permalink)
Don't worry, I first saw this gif half way through engineering school, as well. How is it that we can make it so far in math, without ever being shown this?
GenericCoffee · 1 points · Posted at 17:52:15 on January 9, 2016 · (Permalink)
I dropped out of highschool then got my shit together and dropped out of Oregon state I have literally no clue what's going on or what this represents. I come to explain like I'm five so that I might learn something new and even though I can't appreciate this .gif I appreciate that you appreciate this .gif.
TheGoldenLeo · 1 points · Posted at 17:53:46 on January 9, 2016 · (Permalink)
It's two pie are bro. What's not to get
TrollManGoblin · 1 points · Posted at 18:04:42 on January 9, 2016 · (Permalink)
You should try feading this: http://tauday.com/tau-manifesto
aykcak · 1 points · Posted at 18:12:51 on January 9, 2016 · (Permalink)
Early enough. You are lucky
[deleted] · 1 points · Posted at 18:13:35 on January 9, 2016 · (Permalink)
same here, almost done my engineering degree (two and a half years of part time classes left), I finally get it!
getefix · 1 points · Posted at 18:23:02 on January 9, 2016 · (Permalink)
Ditto. Just finished my last math course (PDE) and never knew this. Wow. Great graphic.
chimpo64 · 1 points · Posted at 18:29:19 on January 9, 2016 · (Permalink)
exactly, me too... i don't think my teacher knows that.
Etherius · 1 points · Posted at 18:37:54 on January 9, 2016 · (Permalink)
Your mind is really going to be blown when you start work with phases (of electricity and electromagnetism) and realize that Pi doesn't belong to circles at all, but to the trig functions.
Pao_Did_NothingWrong · 1 points · Posted at 18:38:09 on January 9, 2016 · (Permalink)
Ten years after my last math class, and it just clicked.
duckandcover · 1 points · Posted at 18:40:48 on January 9, 2016 · (Permalink)
Until now the whole 2 PI R thing just went over your head? That's like some sort of engineering confession bear.
waterloops · 1 points · Posted at 18:51:29 on January 9, 2016 · (Permalink)*
Whoa me too! 3rd year. Have you seen the gif of sin and cos spiraling in 3d? Between this and linear algebra helped me grasp and pass calc 3.
EDIT: formatting, provided link, also the original gif by u/lucasvb is used in this article, thank you for your fine work
lucasvb · 1 points · Posted at 19:24:57 on January 9, 2016 · (Permalink)
Yeah, I've seen it. It's a great way to see complex exponentials!
perl_Help · 1 points · Posted at 18:57:46 on January 9, 2016 · (Permalink)
You might not be cut out for it then
boringcigars · 1 points · Posted at 19:08:51 on January 9, 2016 · (Permalink)
Didn't you see this in high school?
theoneandonlymyself · 1 points · Posted at 19:13:01 on January 9, 2016 · (Permalink)
Same over here, didn't realize it was so easy :p
gurg2k1 · 1 points · Posted at 19:20:37 on January 9, 2016 · (Permalink)
Oh so that's why they call it that.
AngryFace4 · 1 points · Posted at 19:26:20 on January 9, 2016 · (Permalink)
You'd be surprised (or not) by how much you can learn from taking your class notes and googling "ELI5 (insert note here)_"
[deleted] · 1 points · Posted at 19:38:26 on January 9, 2016 · (Permalink)
That gif would have been really nice in my high school geometry class.
presto841 · 1 points · Posted at 19:40:29 on January 9, 2016 · (Permalink)
Don't worry 3rd year biology and I just realized lungs aren't like balloons.
mnr3d · 1 points · Posted at 19:45:01 on January 9, 2016 · (Permalink)
It would be nice if the introduced trig with visualizations like this rather than just requiring memorization of the identities...
SpacemasterTom · 1 points · Posted at 19:48:12 on January 9, 2016 · (Permalink)
Holy shit, same here.
LEGITIMATE_SOURCE · 1 points · Posted at 19:56:36 on January 9, 2016 · (Permalink)
I just don't think people are teaching it right. I mean circumference = pi*diameter
Or pi*2r
2pi rad makes a lot of sense in that context
[deleted] · 1 points · Posted at 20:07:12 on January 9, 2016 · (Permalink)
Got A's through Calc 2 in college without seeing this, idk how, this is so simple
memeticmachine · 1 points · Posted at 20:28:12 on January 9, 2016 · (Permalink)
halfway through fallout, it just clicked.
StabberRabbit · 1 points · Posted at 22:38:48 on January 9, 2016 · (Permalink)
This is how my high school precalc teacher explained radians.
Damn_Dog_Inappropes · 1 points · Posted at 22:47:06 on January 9, 2016 · (Permalink)
Seriously, how the fuck did people learn shit like this before animations existed?? How did they INVENT/DISCOVER this stuff then??
brin722 · 1 points · Posted at 23:16:54 on January 9, 2016 · (Permalink)
I'm so disappointed in all my math teachers after seeing this. I'm a math minor and this is new.
Alkalilee · 1 points · Posted at 23:43:45 on January 9, 2016 · (Permalink)
W-wait, what? I personally prefer radians over degrees and I'm only first year Eng.
fudled · 1 points · Posted at 01:01:47 on January 10, 2016 · (Permalink)
wow, you're fucking stupid
lolthrash · 1 points · Posted at 01:12:54 on January 10, 2016 · (Permalink)
Fully. I'm a final year electrical engineering student and so much of what I do/have done is still just abstract concepts and equations to me
itonlygetsworse · 1 points · Posted at 01:44:43 on January 10, 2016 · (Permalink)
40 years later, it just clicked for me.
mbarnar · 1 points · Posted at 01:52:33 on January 10, 2016 · (Permalink)
Dude no joke, dropped out of engineering, all the sudden I'm ready to go back
chad303 · 1 points · Posted at 02:04:33 on January 10, 2016 · (Permalink)
This is one of many reasons why we should teach radians first in grade school.
Duwelden · 1 points · Posted at 02:41:41 on January 10, 2016 · (Permalink)
TIL my ancestors were a lot smarter than I for coming up with this from scratch. I never even questioned why the math added up like that, lol.
ThatForearmIsMineNow · 1 points · Posted at 02:43:50 on January 10, 2016 · (Permalink)
Please don't take offense to this, but what's there not to get?
zer0t3ch · 1 points · Posted at 02:58:16 on January 10, 2016 · (Permalink)
High school senior who has taken up to pre-calculus, I never realized why it was called radians until now.
rrealnigga · 1 points · Posted at 02:59:32 on January 10, 2016 · (Permalink)
Doubt you're a great student, honestly
Complexifier · 1 points · Posted at 16:43:53 on January 11, 2016 · (Permalink)
More evidence that engineers are retarded.
[deleted] · 1 points · Posted at 09:37:57 on February 1, 2016 · (Permalink)
?
[deleted] · 1 points · Posted at 15:10:06 on January 9, 2016 · (Permalink)*
[deleted]
dunk_hs · -1 points · Posted at 15:35:02 on January 9, 2016 · (Permalink)
If you were an employer/customer would you hire an engineer who doesn't understand basic engineering math?
The fact that this guy got through 3 years is either a miracle or a failure on behalf of his teacher(s).
[deleted] · 1 points · Posted at 15:57:27 on January 9, 2016 · (Permalink)
[deleted]
dunk_hs · 2 points · Posted at 16:14:28 on January 9, 2016 · (Permalink)
Yeah, that's exactly the problem. People get degrees that prove they know stuff they actually don't. In one year this person will be out in the wild designing bridges/electrical/mechanical systems or who knows what other things without knowing what a radian or sin is. It's dangerous to say the least.
Ebolinp · 0 points · Posted at 13:35:31 on January 9, 2016 · (Permalink)
I graduated from Engineering school 10 years ago and I just got it...
dunk_hs · 0 points · Posted at 15:32:24 on January 9, 2016 · (Permalink)
what a disgrace.
ellenkpao · 0 points · Posted at 15:59:19 on January 9, 2016 · (Permalink)
Am I just weird then? Why is it so damn difficult for people to understand this shit? It's not difficult at all. It's either people are way dumber than I thought before...or maybe I'm actually learning a fuckton in my degree program without realizing it (math major)
eeeeeep · 0 points · Posted at 13:29:35 on January 9, 2016 · (Permalink)
Don't know how to ask this question, but what are we adding for pi? The number of pi? So its 3 rads + 3.14 to make half a circumference? What unit is pi in, cm? So sorry I suck at maths.
omgitsbacon · 2 points · Posted at 13:42:52 on January 9, 2016 · (Permalink)
Took me a few times... There are 3 rads shown, then another .16 for 3.16 total, or pi rads in that semi circle. 2pi is the full circle
eeeeeep · 1 points · Posted at 14:03:50 on January 9, 2016 · (Permalink)
Got it, thank you very much!
MAK-15 · 0 points · Posted at 14:13:05 on January 9, 2016 · (Permalink)
Three years? You probably should have asked someone. Not asking questions like that is how you fail the harder classes
bigcat318 · 0 points · Posted at 14:17:53 on January 9, 2016 · (Permalink)
One year into my engineering career, this just clicked
Denziloe · 0 points · Posted at 14:50:53 on January 9, 2016 · (Permalink)
You should really have known what the definition of one radian is by now...
HenryCGk · 0 points · Posted at 15:02:23 on January 9, 2016 · (Permalink)
that's because pi is wrong
Sixtyninelolz · 0 points · Posted at 15:05:11 on January 9, 2016 · (Permalink)
This means you aren't going to be a good engineer.
MyOldNameSucked · 0 points · Posted at 15:06:15 on January 9, 2016 · (Permalink)
How to you get in your 3rd year of engineering without needing that info? I'm in my 2nd year and I have used that so many times.
BBrown7 · 0 points · Posted at 15:12:10 on January 9, 2016 · (Permalink)
Can confirm. Saw this in highschool and basically shit my pants with the sudden flow of calculus I now understand. Am now almost done with my second year of engineering.
SimbaOnSteroids · 0 points · Posted at 15:32:28 on January 9, 2016 · (Permalink)
Same
Kwajalein · 30 points · Posted at 12:09:22 on January 9, 2016 · (Permalink)
1 rad? I'm not wasting a Rad-X on that!
ohyouresilly · 165 points · Posted at 08:43:48 on January 9, 2016 · (Permalink)
thx for the math boner
PartizanParticleCook · 311 points · Posted at 08:51:35 on January 9, 2016 · (Permalink)
Here's some more Fourier pleasure
ohyouresilly · 198 points · Posted at 08:55:31 on January 9, 2016 · (Permalink)
God that is hot, I can hardly function
Problem119V-0800 · 51 points · Posted at 09:47:31 on January 9, 2016 · (Permalink)
Ooh, that wavy line Gibbs me a hardon
[deleted] · 20 points · Posted at 10:28:52 on January 9, 2016 · (Permalink)
If only I had more of these phenomenal gifs to sinc my teeth into.
randypriest · 9 points · Posted at 12:07:58 on January 9, 2016 · (Permalink)
It's a sine of things to come
khmertommie · 3 points · Posted at 12:24:15 on January 9, 2016 · (Permalink)
It's hot cos of the way it is.
Verlepte · 6 points · Posted at 12:36:56 on January 9, 2016 · (Permalink)
Now that's what I call getting off on a tangent...
[deleted] · 1 points · Posted at 13:02:10 on January 9, 2016 · (Permalink)
LOOK AT THEM CURVES
[deleted] · 1 points · Posted at 02:32:10 on January 10, 2016 · (Permalink)
Yo dawg I heard you like derivin' so I put a function in your function so you can derive while you derive.
[deleted] · 41 points · Posted at 11:56:50 on January 9, 2016 · (Permalink)
Interestingly, this is a wonderful demonstration of how epicycles work, and the reason why the geocentrists were able to keep their model by adding more and more epicycles (orbits within orbits within orbits) - they were essentially performing Fourier decomposition of the orbit by hand. It was inelegant and ultimately useless because Kepler showed you can think of it in much simpler terms as an ellipse - but it was mathematically correct.
[deleted] · 14 points · Posted at 12:15:00 on January 9, 2016 · (Permalink)
Yep. Epicycles are virtually complex Fourier analysis. Any smooth curve on the complex plane can be approximated with arbitrary precision.
Just goes to show how overkill and desperate geocentrism is.
XkF21WNJ · 10 points · Posted at 14:52:02 on January 9, 2016 · (Permalink)
Initially heliocentrism still needed epicycles to account for the fact that the orbits aren't perfect circles. Its main advantage was that it needed less of them.
mwobey · 3 points · Posted at 12:53:42 on January 9, 2016 · (Permalink)
I don't know, I think they make some pretty good points. I think we should teach both sides in science class, and let children come to their own conclusion.
Drasern · 8 points · Posted at 13:20:08 on January 9, 2016 · (Permalink)
And then mock them when they reach the wrong one.
DXPower · 3 points · Posted at 14:13:28 on January 9, 2016 · (Permalink)
Then we might as well teach spontaneous generation, steady state theory, intelligent design (already proved to be not science). When you have mountains of evidence and suddenly you have a few people with no formal education that say it's wrong, they don't have any credibility in any academia field. Why should we teach their babbles that often form unnecessarily ad-hoc explanations and make no useful predictions. The reason why we teach only one side in science classes is because the other side can't make any predictions based on a mathematical model, and thus is pseudoscience because it cannot be tested.
There is a great (albeit long) series on YouTube called Testing Geocentrism if you want to learn more about its problems (and it's fairly entertaining as well)
mwobey · 5 points · Posted at 15:51:10 on January 9, 2016 · (Permalink)
Woosh.
Apply /s as needed, I guess. I thought it was self-evident parody.
DXPower · 4 points · Posted at 15:53:18 on January 9, 2016 · (Permalink)
Poe's law.
FUCK_VIDEOS · 1 points · Posted at 17:18:16 on January 9, 2016 · (Permalink)
/r/Geocentrism
[deleted] · 1 points · Posted at 22:19:19 on January 9, 2016 · (Permalink)
No, it's more really the desperateness of people insisting on circular orbits. Heliocentrism itself needed epicycles as well before Kepler came along.
AppearMissing · 7 points · Posted at 11:02:01 on January 9, 2016 · (Permalink)
Show us the extra terms as well!
blitzkraft · 6 points · Posted at 11:17:33 on January 9, 2016 · (Permalink)
Yes. All of them. Don't hold back on us!!
MrRuby · 2 points · Posted at 11:38:42 on January 9, 2016 · (Permalink)
I watched that for way too long.
MuhTriggersGuise · 2 points · Posted at 12:46:21 on January 9, 2016 · (Permalink)
Could've left the 4/pi factor out of all the equations and used the same plots.
[deleted] · 2 points · Posted at 13:05:05 on January 9, 2016 · (Permalink)
Holy shit. I have been working with FFTs for years and never pictured it this way. Mind blown.
PartizanParticleCook · 2 points · Posted at 22:40:36 on January 9, 2016 · (Permalink)
I remember when it first clicked in my mind, I had to just sit there for a couple of minutes whilst everything I learnt about the frequency domain clicked into place.
[deleted] · -5 points · Posted at 16:17:43 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 3 points · Posted at 16:53:34 on January 9, 2016 · (Permalink)
What a useless comment. And how fucking rude.
There are many ways of considering, visualising and using mathematical constructs, and contexts within which to apply them. To see them in a different way is just that. It doesn't make the work I've done with them so far useless or invalid. To try to belittle someone for not seeing them the way you perhaps saw them is petty and belies deep insecurity. Seriously, what value did you add to this? What is the point of anything you said? Nothing.
Take your rude, condescending and needless insult and fuck off back to your sperglord mindpalace.
fuckitimatwork · 2 points · Posted at 17:09:01 on January 9, 2016 · (Permalink)
Hnnngggg
laseralex · 1 points · Posted at 11:42:55 on January 9, 2016 · (Permalink)
I came.
Wiggity_Wooty_PM_Dat · 1 points · Posted at 12:52:58 on January 9, 2016 · (Permalink)
So replacing that number with increasing prime numbers makes ever increasingly wider Batmen?
BiblioPhil · 1 points · Posted at 23:44:02 on January 9, 2016 · (Permalink)
Wow, even fourier than I thought. Look at all those fours!
lucasvb · 248 points · Posted at 11:51:57 on January 9, 2016 · (Permalink)
I'm the author. You're welcome!
Here's my gallery of Wikipedia animations if you want more.
[deleted] · 27 points · Posted at 12:13:48 on January 9, 2016 · (Permalink)
Hey with what software do you make the animation?
lucasvb · 186 points · Posted at 13:15:27 on January 9, 2016 · (Permalink)
This is covered in the FAQ, but I'll write a bit more about it here.
I use a custom-drawing library for 2D/2.5D and POV-Ray for the fancy 3D stuff. The drawing library was cumulatively developed over the years on top of GD in PHP, due to historical reasons.
Most existing software are too specific and/or too cumbersome to do the kind of stuff I want to do. I always need some artistic freedom they didn't offer, or which is pretty hard to achieve. So I had to use a drawing library. Check the FAQ for more on this.
Now, I've been working on a similar library using OpenGL and Python, but I'm having problems getting the hang of shaders. Looks like I'll have to roll out my own line and polygon drawing stuff too, which I'm fine with since it'll be a good way to learn OpenGL.
I'm doing this because I've been working on a YouTube channel where I'll use more technical animations and narration to explain math and physics concepts to a general audience.
Most YouTube channels are superficial about math and physics ("an electron is a particle... AND a wave! wow!", and then the video ends) or too technical (some dude boringly writing on a paper/chalkboard, pretty much a formal lecture, an ancient format that isn't trying anything new).
I think there's room for improvement. But for the videos I'd need a larger amount of frames at 1080p and my current setup isn't going to work.
Plasma_000 · 36 points · Posted at 13:41:28 on January 9, 2016 · (Permalink)
Wow, I'm super excited for this youtube channel. 10/10 would watch. Subscribed already
electricx99 · 14 points · Posted at 13:52:23 on January 9, 2016 · (Permalink)
I did too. Looking forward to the first video
lucasvb · 8 points · Posted at 14:16:49 on January 9, 2016 · (Permalink)
Thanks. Just be gentle on me, I still have a lot of work ahead of me! I'm hoping to have the first video up before April.
pavel_lishin · 2 points · Posted at 18:53:32 on January 9, 2016 · (Permalink)
Ditto.
H2C2O4 · 5 points · Posted at 22:10:12 on January 9, 2016 · (Permalink)
I recognize a large portion of your illustrations from reading various Wikipedia-articles over the years. Only yesterday I saw your scalar field png! It's amazing how much a good illustration can aid the understanding of a concept, and it's so easy to forget that there is a person behind every line of text and every picture. I'm almost as star struck right now as when the guy who made solitaire for Windows showed up on reddit not long ago.
DXPower · 3 points · Posted at 14:49:05 on January 9, 2016 · (Permalink)
You should look at King Crocoduck's Quantum Theory Made Easy series, he goes over the history and math of duality without boring you and making it easy to understand, great videos if you want some ideas on how to structure it
lucasvb · 3 points · Posted at 14:53:54 on January 9, 2016 · (Permalink)
Cool, I'll take a look. Thanks for the suggestion!
optigon · 2 points · Posted at 17:08:06 on January 9, 2016 · (Permalink)
Curious, but have you looked at Processing as a language to help you with your animations? It's largely designed for visual representation.
lucasvb · 3 points · Posted at 17:21:42 on January 9, 2016 · (Permalink)
Yes, but the real time paradigm is not acceptable for me. It's also very difficult to deal with certain high-level features I need to add.
TRexRoboParty · 1 points · Posted at 23:05:29 on January 10, 2016 · (Permalink)
Processing is great for non-realtime usage too - I've seen examples of people generating images over time using genetic algorithms for example, or making movies/gifs by rendering out a series of jpgs etc. For example, this Hypercube gif is probably somewhat along the lines of your explanation circle gif (though obviously I've no idea what you've got planned for the future!). The author has a lot of neat geometric gifs: https://twitter.com/bigblueboo
I'd also recommend checking out OpenFrameworks - there's a huge amount of extensions/plugins available for things like editor interfaces, UI, post-processing effects etc. Processing has those too, but for some reason I find myself more productive in OF. Either way, good luck with the project! I'm definitely looking forward to the Youtube channel :)
why_no_aubergines · 2 points · Posted at 21:30:44 on January 9, 2016 · (Permalink)
High five for POV-Ray! :D
nfsz · 3 points · Posted at 15:17:53 on January 9, 2016 · (Permalink)*
You could start an indiegogo campaign to crowdfund a better computer setup. Ill help and i'm sure many others will be willing to help
lucasvb · 10 points · Posted at 15:27:59 on January 9, 2016 · (Permalink)
Thank you for the suggestion. But it's not the computer setup. It's really a matter of expanding the range of stuff I can do and how fast I can make animations. It's a software thing.
With my new Python+OpenGL engine I'll even have real time interactivity that will help me choose angles and adjust parameters before I make the final, high quality renders. Right now, I have to adjust and re-render all the frames, which takes a long time sometimes. A new engine will speed up things immensely.
I also don't want to disappoint anyone at this moment, so I'm taking things in my own pace. I know there's a lot of interest for this sort of material out there, and I'm excited to be able to provide it, but I wouldn't want to leave people who made a monetary investment waiting for too long. I have a lot of other personal stuff going on in my life that could get in the way.
Once my YouTube channel is going, I'll set up a per-video Patreon account so that I can keep things fair, and so people can show their support.
nfsz · 3 points · Posted at 15:39:27 on January 9, 2016 · (Permalink)
I completely understand. And as an aspiring programmer, I love how you don't settle with the limitations of the design tools already out there and craft your own solutions!
lucasvb · 5 points · Posted at 15:43:16 on January 9, 2016 · (Permalink)
Hah, I'm just a stubborn bastard. But I wouldn't have done if I wasn't into developing low level stuff. It's fun to work with the basics. Big applications are not for me.
EliteTK · 1 points · Posted at 19:33:15 on January 9, 2016 · (Permalink)*
Will this library be released under a permissive license as open source?
If you put your code on github I would be willing to help with the shaders.
Simply do as most other projects do, include a TODO for each directory explaining what needs to be done or create a list of issues for people to post PRs against.
Edit: Now I know where all those wikipedia GIFs come from.
lucasvb · 1 points · Posted at 19:35:14 on January 9, 2016 · (Permalink)
Yeah, I hope to release the Python+OpenGL library at some point. But I'm super inexperienced with OpenGL so this is probably going to be a disaster. I don't think I'm a particularly good developer.
EliteTK · 2 points · Posted at 19:57:56 on January 9, 2016 · (Permalink)
Even more reason to release it, you can learn a lot more from people criticising your work on a public platform than you will from trying to discover your own mistakes and solve them.
The point is, if your tool in any way actually solves a problem (it solved a problem for you) even if it's not particularly well written, it will attract developers who will first help put it in shape and then continue to make it better.
protestor · 1 points · Posted at 21:07:04 on January 9, 2016 · (Permalink)
Well release it as a work in progress anyway.
ferozer0 · 1 points · Posted at 14:18:53 on January 9, 2016 · (Permalink)
Subbed.
soliloki · 1 points · Posted at 14:48:27 on January 9, 2016 · (Permalink)
This is great! I'm subscribing!
DrJoeOopa · 1 points · Posted at 17:39:27 on January 9, 2016 · (Permalink)
Consider myself subscribed to your channel. Hope to see your content in there soon :)
blbd · 1 points · Posted at 19:10:17 on January 9, 2016 · (Permalink)
You seem like the type of guy they could really use on a temporary posting to the CTO's office in the White House. I an hoping to do one someday if I can get some money from options at a startup at some point in my career.
1337Gandalf · 1 points · Posted at 19:29:39 on January 9, 2016 · (Permalink)
I need to learn more of this kind of thing, where do I start?
protestor · 2 points · Posted at 21:08:58 on January 9, 2016 · (Permalink)
Even though he eventually discarded Processing for his own usage, if you wanted to learn how to do this kind of stuff you could do far worse than learning how to program in Processing.
Also see /r/loadingicon and other subreddits where this kind of animation is sometimes posted.
lucasvb · 1 points · Posted at 19:31:29 on January 9, 2016 · (Permalink)
Not sure what "this kind of thing" is specifically.
1337Gandalf · 1 points · Posted at 21:45:09 on January 9, 2016 · (Permalink)
high level geometry math.
I don't have a degree in mathematics, but I'm interested in this, where should I start?
TRexRoboParty · 2 points · Posted at 02:08:21 on January 10, 2016 · (Permalink)
Khan Academy have a whole slew of videos focused on teaching in a straightforward manner. Geometry & trigonometry are covered, but they cover a whole lot ranging from basic arithmetic to calculus.
protestor · 1 points · Posted at 21:05:32 on January 9, 2016 · (Permalink)
Do you keep your code under version control (like Git)? If not, you should.
In any case, you could just dump the code as-is to Github or something, even if nobody would use it.
And if you have both the code and the images under version control, that's already useful (it doesn't matter if the code is constantly changing if you can match each image to the source used to render part of it)
deshe · 1 points · Posted at 21:30:56 on January 9, 2016 · (Permalink)
Hi, I am a math Ph.D student and a TA, and I often get ideas for animations which I think could be pedagogical and fun. Are you open to suggestions?
lucasvb · 1 points · Posted at 21:47:17 on January 9, 2016 · (Permalink)
Always. No guarantees, though.
salmix21 · 1 points · Posted at 21:32:27 on January 9, 2016 · (Permalink)
Did you major in anything physics related?
lucasvb · 3 points · Posted at 21:47:33 on January 9, 2016 · (Permalink)
I major in physics.
Vacster · 1 points · Posted at 00:38:14 on January 10, 2016 · (Permalink)
Oh man, OpenGL shaders are hell, the first time I dived into them I spent like 8 hours trying to dynamically change the color, I feel you man. Good luck with your project!
[deleted] · 1 points · Posted at 00:40:29 on January 10, 2016 · (Permalink)
POVRay! Holy hell that brings back memories of ~1996, starting a render on my 386 in the morning and going to school, hoping that it might be done before bedtime that night...
[deleted] · 1 points · Posted at 03:23:10 on January 10, 2016 · (Permalink)
Have you ever tried blender?
______DEADPOOL______ · 0 points · Posted at 22:59:16 on January 9, 2016 · (Permalink)
SUB FUCKING SCRIBED D:
More videos please!
Allong12 · 9 points · Posted at 12:40:43 on January 9, 2016 · (Permalink)
Have you tried clicking the link he gave you?
ChiefSchniplock · 3 points · Posted at 12:55:01 on January 9, 2016 · (Permalink)
He already told you.
http://en.wikipedia.org/wiki/User:LucasVB/Gallery
JimmyLuckyChance · 2 points · Posted at 13:09:43 on January 9, 2016 · (Permalink)
http://1ucasvb.tumblr.com/faq
Stiffo90 · 13 points · Posted at 12:15:30 on January 9, 2016 · (Permalink)
You do sexy animations. Could you please do animations of common sorting algorithms as well? :) I mean, there are of course animations, they just aren't satisfying like eg. your radians one.
lucasvb · 12 points · Posted at 13:50:12 on January 9, 2016 · (Permalink)
Yes. I've been thinking about alternative visualizations of several algorithms in computer science and computer graphics. Keep an eye out.
Godd2 · 3 points · Posted at 15:01:11 on January 9, 2016 · (Permalink)
Mike Bostock (creator of d3.js) has a whole page of amazing algorithm visualizations. If you haven't seen them, they might be good reference/inspiration. (My favorite is the maze turning into a binary tree on the bottom)
lucasvb · 1 points · Posted at 15:04:48 on January 9, 2016 · (Permalink)
I've seen them all, it's a great source of inspiration. I intend to use d3.js for some interactive stuff to accompany my YouTube channel.
FuckingaFuck · 7 points · Posted at 13:07:52 on January 9, 2016 · (Permalink)
I'm a high school math teacher and I've used these to help my students visualize sine and completing the square. Your work is spectacular, thank you!
lucasvb · 8 points · Posted at 13:40:10 on January 9, 2016 · (Permalink)
Makes me happy to know these are being used like this. I hope they liked them!
Thanks!
NeokratosRed · 5 points · Posted at 12:28:53 on January 9, 2016 · (Permalink)
Holy crap, you basically made most of the educational gifs I love !
Thank you so much!
lucasvb · 7 points · Posted at 13:48:16 on January 9, 2016 · (Permalink)
Thanks for the appreciation! And you're welcome.
[deleted] · 5 points · Posted at 12:38:40 on January 9, 2016 · (Permalink)
Your animations make me believe I could almost not suck at math.
lucasvb · 8 points · Posted at 13:52:13 on January 9, 2016 · (Permalink)*
I'm glad I can give you that impression. I do believe animations and interactive illustrations, paired with a proper and new teaching strategy, can really make a huge difference in math and physics education.
MamaduCookie · 3 points · Posted at 12:24:23 on January 9, 2016 · (Permalink)
I know nothing about physics and only a little mathematics but I watched a lot of your animations and found them fascinating. Thanks.
[deleted] · 3 points · Posted at 15:15:24 on January 9, 2016 · (Permalink)*
[deleted]
lucasvb · 1 points · Posted at 15:17:27 on January 9, 2016 · (Permalink)
Yep. Been at it for over ten years. God, I'm old.
Glad I could help!
atoge1 · 2 points · Posted at 12:16:18 on January 9, 2016 · (Permalink)
You, sir, are amazing.
lucasvb · 1 points · Posted at 13:50:31 on January 9, 2016 · (Permalink)
Thanks!
Forrestfunk · 2 points · Posted at 12:32:03 on January 9, 2016 · (Permalink)
I also would like to know how you make those nice animations, what software you use!
lucasvb · 2 points · Posted at 13:50:59 on January 9, 2016 · (Permalink)
Check this comment.
DanGNU · 2 points · Posted at 12:39:48 on January 9, 2016 · (Permalink)
I just want to say one thing, you are awesome.
Jumpmobile · 2 points · Posted at 13:05:00 on January 9, 2016 · (Permalink)
Good work! Do you have anything like flattr?
lucasvb · 6 points · Posted at 13:41:18 on January 9, 2016 · (Permalink)
You can donate via PayPal at the moment. I'll have a Patreon once my YouTube channel is up.
Since I've been busy with other stuff for the past year and so, I haven't made anything new. But I'm working on big things.
inherent-boredom · 1 points · Posted at 13:48:14 on January 9, 2016 · (Permalink)
Well, i'm not in a financially stable situation to make donation, yet i'm very glad to be one of your very first subscribers. Keep it up!
plasticenewitch · 1 points · Posted at 18:17:57 on January 9, 2016 · (Permalink)
This home school mom says thank you very much!
fupreviousotterpops · 1 points · Posted at 12:51:30 on January 9, 2016 · (Permalink)
This is so helpful. I might have stood a chance in math had I had something like this. Thank you!
DendariaDraenei · 1 points · Posted at 13:05:15 on January 9, 2016 · (Permalink)
heavy breathing
DeltaPositionReady · 1 points · Posted at 13:18:49 on January 9, 2016 · (Permalink)
Not sure if my maths is on the right track here but the "Converting from Cartesian to Polar coordinates" animation, would that be how Radiation plots are calculated?
My thinking is that in the instance of a radio antenna sending out RF energy, the frequency and the power and modulation etc would be relevant to the pattern that it would propagate within?
Or am i just grasping at straws?
aya_mangelou · 1 points · Posted at 13:42:41 on January 9, 2016 · (Permalink)
Those are awesome! Particularly your gifs for the line integral of a vector field and completing the square are the best imho.
thebiggerbang · 1 points · Posted at 13:44:01 on January 9, 2016 · (Permalink)
This is legitimately the best thing that I've seen this week!
seaandtea · 1 points · Posted at 13:44:26 on January 9, 2016 · (Permalink)
I do want more...I got more...I am so late for ballet because of these pretty moving pictures :)
dumbredditer · 1 points · Posted at 14:47:59 on January 9, 2016 · (Permalink)
I went to this page hours ago. I totally forgot how I even you there after a while.
[deleted] · 9 points · Posted at 13:04:30 on January 9, 2016 · (Permalink)
So rad
OrangeIsARat · 14 points · Posted at 12:27:26 on January 9, 2016 · (Permalink)
This gif did what 4 years of high school math failed to do. Thanks for posting this.
stevemcblark · 42 points · Posted at 11:00:06 on January 9, 2016 · (Permalink)
Dude, that gif is pretty rad.
HAHA_goats · 1 points · Posted at 13:45:03 on January 9, 2016 · (Permalink)
rad
tpgreyknight · 1 points · Posted at 01:08:58 on January 10, 2016 · (Permalink)
Take your upvote and get out of here.
[deleted] · 7 points · Posted at 12:29:32 on January 9, 2016 · (Permalink)
Reddit needs a /r/helpfulmathgifs
mcfandrew · 10 points · Posted at 14:44:54 on January 9, 2016 · (Permalink)
well, there is /r/mathgifs. How helpful they are is a matter of personal preference.
[deleted] · 1 points · Posted at 03:13:33 on January 10, 2016 · (Permalink)
Seems pretty helpful. Thanks
flurrux · 2 points · Posted at 17:20:05 on January 9, 2016 · (Permalink)
will /r/mathgifs/ do?
[deleted] · 1 points · Posted at 03:13:23 on January 10, 2016 · (Permalink)
Yes!
sbb618 · 2 points · Posted at 23:56:12 on January 9, 2016 · (Permalink)
/r/educationalgifs and /r/mathgifs have a ton of them.
[deleted] · 1 points · Posted at 03:13:14 on January 10, 2016 · (Permalink)
Thanks!
phd2k1 · 15 points · Posted at 10:25:22 on January 9, 2016 · (Permalink)
What is the benefit of dividing a circle this way? Is there a practical reason to use this instead of 360 or 100?
simarilli · 62 points · Posted at 11:08:06 on January 9, 2016 · (Permalink)
This way sin and cos are related to the exponential function without any ugly conversion factors in the arguments. If our angle x is measured in radians, then cos(x) = (eix + e-ix )/2. If x is measured in degrees, it becomes cos(x) = (eixpi/180 + e-ixpi/180 )/2
Where you're more likely to meet the distinction explicitly is in calculus, where if x is measured in radians then d/dx sin(x) = cos(x) and d/dx cos(x) = -sin(x), but if x is measured in degrees you have to include a conversion factor.
PM_ME_UR_GAPE_GIRL · 44 points · Posted at 12:26:58 on January 9, 2016 · (Permalink)
I see
verheyen · 21 points · Posted at 13:11:34 on January 9, 2016 · (Permalink)
Now apply what you have learned to the gapes.
[deleted] · 1 points · Posted at 15:22:09 on January 9, 2016 · (Permalink)
Gonna need a gif to explain this.
simarilli · 5 points · Posted at 15:55:09 on January 9, 2016 · (Permalink)
Not in gif format, but I quite like this image. Definitely not ELI5 though.
Rangsk · 35 points · Posted at 11:16:57 on January 9, 2016 · (Permalink)
Radians are the only measurement of angle that is unitless. Radians are defined as the ratio of the arclength (s) and the radius (r), which is s/r. Since s and r are the same unit, it doesn't matter which unit you use for the length, as it cancels out.
Any other way of expressing angles is going to require using a unit, such as degrees.
Why is this beneficial? Well, if you have to use a unit for an angle, then random annoying constants start appearing due to the need to do unit conversions. Here's one example:
In radians:
In degrees:
If you were to use degrees, you'd have to keep sprinkling this (π/180) constant everywhere, which is annoying and unnecessarily complicated.
Kayyam · 53 points · Posted at 12:55:59 on January 9, 2016 · (Permalink)
You're wrong. Radian is not unitless since Radian is an unit. The word you're looking for is "dimensionless".
And degrees is also a unit which is also dimensionless.
The only reason the derivative works better in Radian than Degrees is not because of one being a unit and the other not, but because Pi is at the heart of mathematics while 360 (an arbitrary number inherited from Babylonians diving stuff in 60 parts instead of 10 or 100) isn't.
Akijojo · 10 points · Posted at 14:42:42 on January 9, 2016 · (Permalink)
This comment made me realize how weird "an unit" sounds.
ThePantsParty · 17 points · Posted at 17:26:32 on January 9, 2016 · (Permalink)
(That's because it's incorrect grammar)
marknutter · 1 points · Posted at 00:40:47 on January 10, 2016 · (Permalink)
Maybe /u/Kayyam pronounces it "oonit" instead of "unit".
Kayyam · 1 points · Posted at 00:54:24 on January 10, 2016 · (Permalink)
Took me a while to figure out what you guys were talking about!
bobberpi · 7 points · Posted at 18:16:30 on January 9, 2016 · (Permalink)
A ñunit
Up_to_11 · 1 points · Posted at 20:55:28 on January 9, 2016 · (Permalink)
An ewt
bobberpi · 1 points · Posted at 21:30:03 on January 9, 2016 · (Permalink)
She turned me into an ewt!
BlindSoothsprayer · 1 points · Posted at 19:22:27 on January 9, 2016 · (Permalink)
It really bothers me when people use the wrong indefinite article. Acronyms/initialisms can be especially tricky.
teh_tg · 3 points · Posted at 13:55:21 on January 9, 2016 · (Permalink)
Rangsk might be technically wrong but if you replace one word with anothere then its explanation is nice.
Parsel_Tongue · 7 points · Posted at 16:37:09 on January 9, 2016 · (Permalink)
No he's not.
Radians are not the only dimensionless unit.
There are all sorts of units which could be dimensionless.
I could just as easily have a single unit which is the full rotation of the circle.
The advantage of using radians is that it makes (sinx)/x =1 for very small values of x, this means that it has a gradient of 1 and a derivative of cos(x).
Other dimensionless units will not do this.
dongmaster42 · 1 points · Posted at 17:06:31 on January 9, 2016 · (Permalink)
no, 2pi is at the heart of mathematics. if it was pi, you'd still have conversion factors when you differentiated.
Noncomment · 1 points · Posted at 19:11:09 on January 9, 2016 · (Permalink)
Well 360 isn't arbitrary, it's a highly divisible number. Whereas using 2pi as a unit isn't divisible at all, and all measurements will have infinite nonrepeating digits.
Kayyam · 1 points · Posted at 22:27:07 on January 9, 2016 · (Permalink)
In algebra, the digits are irrelevant.
Noncomment · 2 points · Posted at 23:02:13 on January 9, 2016 · (Permalink)
Yes but in real life they are not. All I'm saying is the number isn't arbitrary and the Babylonians were really smart in selecting 360.
cephas384 · 1 points · Posted at 19:35:50 on January 9, 2016 · (Permalink)
SI treats radians as dimensionless. When you calculate an arc length, the product of a length and an angle is a length. It doesn't always make the most sense, though.
Kayyam · 2 points · Posted at 22:26:12 on January 9, 2016 · (Permalink)
Isn't that exactly what I'm saying? Radians are dimensionless. The product of a radian by a length is obviously a length. Why doesn't it make sense?
fuckwpshit · 2 points · Posted at 12:43:47 on January 9, 2016 · (Permalink)
Thanks for clearing this up, I was wondering why and TIL.
KapteeniJ · 6 points · Posted at 10:54:28 on January 9, 2016 · (Permalink)
It's probably derived from Babylonian mathematics, their number system was based on number 60, similar to how ours is based on 10. I couldn't find any hard source for how 360 came about, though.
60 is a nice number because you can divide it evenly by all the common factors, 2, 3, 4, 5, 6, 8, 10, 12, 15. Allows you to do math with integers longer even if you have to deal with division.
Artefact2 · 8 points · Posted at 12:31:46 on January 9, 2016 · (Permalink)
It probably comes from the ~360 days in a year. The babylonians noticed that, and chose their base accordingly.
Noncomment · 1 points · Posted at 19:13:08 on January 9, 2016 · (Permalink)
No that's just a coincidence. 360 is a highly divisible number, which makes it very convenient to use as a base.
Kayyam · 0 points · Posted at 12:59:04 on January 9, 2016 · (Permalink)
Probably not since there aren't 360 days in a year.
It comes from the sexagesimal base used by them before that and they used that base because 60 is a highly composite number.
Artefact2 · 2 points · Posted at 13:13:20 on January 9, 2016 · (Permalink)
The babylonians couldn't have known that. From empirical obvervations (ie seasons, etc.) it makes sense to guess a roughly 360-day cycle.
Kayyam · 1 points · Posted at 13:18:57 on January 9, 2016 · (Permalink)
It's not so obvious, it doesn't take much to figure out the length of a year (there is another comment on this thread that says the same thing).
It's much more safe to assume that 360 is just 6*60 with 60 being the base of the whole measurement system.
[deleted] · 2 points · Posted at 14:38:32 on January 9, 2016 · (Permalink)
They had two calendars: a lunar (354 days) and a solar (365). (http://www.livius.org/articles/concept/calendar-babylonian/) Maybe they averaged to get the 360?
[deleted] · 1 points · Posted at 13:06:42 on January 9, 2016 · (Permalink)
Also 60 minutes in an hour, 60 seconds in a minute, etc.
diakked · 1 points · Posted at 14:09:51 on January 9, 2016 · (Permalink)
This. 12 is magic. Same reason we have 24 hours in a day (12 am, 12 pm) and 60 minutes in an hour. 10 and powers of 10 don't divide nicely into thirds or sixths or eighths.
[deleted] · -3 points · Posted at 11:27:02 on January 9, 2016 · (Permalink)
[deleted]
JonnyLakey · 5 points · Posted at 11:41:19 on January 9, 2016 · (Permalink)
No, since dividing a circle into 360° is older than the metric system. It is almost certainly to do with the divisibility of 360.
KapteeniJ · 3 points · Posted at 13:29:47 on January 9, 2016 · (Permalink)
That's related to base 60, yeah, because you have 60 minutes in hour and 60 seconds in a minute, and 1000 meters in a kilometer.
However, circle is divided into 360 degrees, and each degree is divided into 60 arc minutes, which are further divided into 60 arc seconds. You type them out 180°45'1" for 180 degrees, 45 arc minutes and 1 arc second. Minutes and seconds are in the wrong place there. I mean, it seems to relate to 60-base number system, but I can't really see any big singular reason why 360 precisely.
haagiboy · 1 points · Posted at 19:51:06 on January 9, 2016 · (Permalink)
Thanks! :)
ReallyNiceGuy · 1 points · Posted at 11:47:21 on January 9, 2016 · (Permalink)
Probably not, as the meter was made in the 1600s. Degrees go much farther back to the Ancient Greeks.
Also, I doubt time has much to do with a full circle.
w2qw · 1 points · Posted at 11:58:41 on January 9, 2016 · (Permalink)
The 3.6 there mainly comes from 3600s being equal to 1h which is from the Babylonian mathematics, but obviously predates SI units.
asimillo · 1 points · Posted at 11:32:39 on January 9, 2016 · (Permalink)
Try and take out the derivate of the sinus (etc) function without rads
jofwu · 1 points · Posted at 13:25:55 on January 9, 2016 · (Permalink)
They directly relate the angle with the length of the radius. This becomes useful for many reasons. That's the short answer.
TheWrongFusebox · 8 points · Posted at 08:35:37 on January 9, 2016 · (Permalink)
Nice.
Doublebhn · 31 points · Posted at 10:11:48 on January 9, 2016 · (Permalink)
rad!
[deleted] · 3 points · Posted at 09:01:19 on January 9, 2016 · (Permalink)
[deleted]
gregorthebigmac · 2 points · Posted at 19:41:34 on January 9, 2016 · (Permalink)
That's not strange. It's a very perishable skill. Most math is, but I found trig to be the most perishable. The less you use it, the less likely you are to remember it.
Lollipop126 · 9 points · Posted at 12:23:33 on January 9, 2016 · (Permalink)
Holy shit, that's why circumference is 2pi x r
BlindSoothsprayer · 2 points · Posted at 19:26:31 on January 9, 2016 · (Permalink)
Well, it's not exactly the reason why. I might be getting a little Platonic here, but circumference is 2pi x r because it's just a fact that can be measured or calculated. More accurately, circumference being 2pi x r is the reason why a radian is defined the way it is.
AceDecade · 3 points · Posted at 23:00:15 on January 9, 2016 · (Permalink)
I think the word you're looking for is "pedantic"?
BlindSoothsprayer · 1 points · Posted at 23:09:15 on January 11, 2016 · (Permalink)
That too, but I fully intended to write "Platonic." As in, I believe abstract numbers actually exist in the physical universe. Otherwise, it might not make sense to say that "one math thing is the reason why another math thing is". You know, people who believe math is a collective figment of human's imaginations might have an issue with that.
keveready · 1 points · Posted at 15:48:33 on January 9, 2016 · (Permalink)
What's the difference between pi rad and 1/2 circumference?
Minkar · 1 points · Posted at 17:44:23 on January 9, 2016 · (Permalink)
Well, the difference is that pi radians is an angle, where as 1/2 circumference is a distance. Though they are intimately related, as an angle of pi rad (180 degrees) produces an arc which creates a semi circle, or half the circumference.
landingshortly · 6 points · Posted at 10:24:04 on January 9, 2016 · (Permalink)
Harr. harr. Pi-rad.
samsg1 · 7 points · Posted at 11:49:03 on January 9, 2016 · (Permalink)
I have a degree in physics.. I finally got radians. Thank you!
[deleted] · 1 points · Posted at 20:24:21 on January 9, 2016 · (Permalink)
I'm confused how you couldn't get it before
C = 2πr
so if you say there are 2π radians in a circle then the length of the arc subtended by 1 radian (ie 1/(2π) of a circle) is 2π.r/(2π) which is simply r.
C/(2π) = r
What's more helpful is that all the relationships are simplified by the 2π factor. It's just a substitution to make things easier. Look at that first equation:
C = 2πr
What are you going to pick to make this simple? That's right 2π.
PartizanParticleCook · 1 points · Posted at 22:45:12 on January 9, 2016 · (Permalink)
Better late than never
DarthFarious · 2 points · Posted at 12:54:57 on January 9, 2016 · (Permalink)
So radians is actually just radii?
[deleted] · 1 points · Posted at 20:25:38 on January 9, 2016 · (Permalink)
No
Brarsh · 1 points · Posted at 04:29:59 on January 10, 2016 · (Permalink)
Well, it's a hint as to what it is by having a similar name. The radius is used to travel that distance around the circle, and the angle that the starting point and ending point in relation to the center of the circle is 1 radian. The "pizza slice" that it makes has 2 straight sides 1 radius long and one curved side 1 radius long.
_schweddy_balls · 2 points · Posted at 13:21:47 on January 9, 2016 · (Permalink)
So the circumference of every circle is 2 pi r?
[deleted] · 1 points · Posted at 20:15:39 on January 9, 2016 · (Permalink)
C = πd
You had to ask?
PartizanParticleCook · 1 points · Posted at 22:39:20 on January 9, 2016 · (Permalink)
Exactly.
[deleted] · 2 points · Posted at 13:59:31 on January 9, 2016 · (Permalink)
TIL radians are a unit and not just the name of this approach.
breawycker · 2 points · Posted at 14:17:19 on January 9, 2016 · (Permalink)
Wikipedia has the best gifs
JimeDorje · 2 points · Posted at 14:21:25 on January 9, 2016 · (Permalink)
This fucking blew my mind.
Dinah_Mo_Hum · 2 points · Posted at 15:04:34 on January 9, 2016 · (Permalink)
That is so hot
GENERIC-WHITE-PERSON · 2 points · Posted at 15:10:00 on January 9, 2016 · (Permalink)
That's http://m.imgur.com/JZyK3Ps
Wishyouamerry · 2 points · Posted at 15:22:21 on January 9, 2016 · (Permalink)
Once I saw "Π rad" I expected some guy in an eye patch to pop up and say, "Aye, mately! This be my circle because I'm a pi-rad. Argh!"
DavidMalchik · 2 points · Posted at 15:48:56 on January 9, 2016 · (Permalink)
Took me awhile to realize that after 3 rad comes pi rad which is 3.14... very cool. Excellent visualization! Thank you!
[deleted] · 2 points · Posted at 16:02:06 on January 9, 2016 · (Permalink)
You know. If my geometry teacher showed me this way for a lot of concepts, I would have understood a hell of a lot more.
I struggled so much with math in grade school and elementary school because it was just "this is the formula. Learn this shit."
Then, since I didn't understand HOW the formulas are developed, I'd panic and forget which thing went where on test day and screw it up.
PartizanParticleCook · 1 points · Posted at 22:33:57 on January 9, 2016 · (Permalink)
That is the biggest flaw in the education system, making you learn what the end result is and not how you get there and why. Never too late if you want to turn it round though!
doGoodScience_later · 2 points · Posted at 16:23:16 on January 9, 2016 · (Permalink)
Aerospace engineer here. Made an account just to comment. These are brilliant. Learned alot from those gifs. Well done
PartizanParticleCook · 1 points · Posted at 22:25:36 on January 9, 2016 · (Permalink)
No worries, very happy to help you.
Ansonm64 · 2 points · Posted at 16:27:08 on January 9, 2016 · (Permalink)
This is the most I've ever understood this. Thank you.
PartizanParticleCook · 1 points · Posted at 22:25:02 on January 9, 2016 · (Permalink)
Glad to help
F1RST_WORLD_PROBLEMS · 2 points · Posted at 16:32:58 on January 9, 2016 · (Permalink)
I didn't even care about this post, but it is a perfectly simple explanation. Well done.
infosackva · 2 points · Posted at 16:35:02 on January 9, 2016 · (Permalink)
Holy shit
Cybertronic72388 · 2 points · Posted at 17:08:16 on January 9, 2016 · (Permalink)
The Pi Rad is like a hotfix patch. You couldn't divide it all evenly without it. Pi is there to just make it work.
xArchitectx · 2 points · Posted at 17:52:30 on January 9, 2016 · (Permalink)
Holy shit. I'm in my twenties, always excelled in Mathematics. It has never been explained to me like this but it all makes sense now! You're amazing thank you!
PartizanParticleCook · 1 points · Posted at 22:22:09 on January 9, 2016 · (Permalink)
Some stuff just needs to be visualised, glad to have helped you. May the trig be with you
Go_Fonseca · 2 points · Posted at 18:30:37 on January 9, 2016 · (Permalink)
This animation would have been so useful back in my college days.
JusticeBeaver13 · 2 points · Posted at 18:40:31 on January 9, 2016 · (Permalink)
6.28 radians = ~360 degrees
[deleted] · 2 points · Posted at 18:48:47 on January 9, 2016 · (Permalink)
mother of god.
Apache1080 · 2 points · Posted at 19:31:09 on January 9, 2016 · (Permalink)
You saved my second semester precal grade. Thank you.
PartizanParticleCook · 1 points · Posted at 22:20:17 on January 9, 2016 · (Permalink)
Happy to help. Maths is to be enjoyed, not hated.
Chief_Tallbong · 2 points · Posted at 20:17:36 on January 9, 2016 · (Permalink)
I don't know what any of this means and I still feel like I learned something. Excellent visualization(?)
TALQVIST · 2 points · Posted at 20:56:59 on January 9, 2016 · (Permalink)
Finally answered the question I've asked teachers since elementary school. Thanks.
viewerdoer · 2 points · Posted at 21:15:36 on January 9, 2016 · (Permalink)
Omg i finally understand pi at age 27 through a gif
PartizanParticleCook · 1 points · Posted at 22:16:10 on January 9, 2016 · (Permalink)
ᕕ( ՞ ᗜ ՞ )ᕗ
[deleted] · 2 points · Posted at 21:37:32 on January 9, 2016 · (Permalink)
Brilliant
elcheeserpuff · 2 points · Posted at 23:30:11 on January 9, 2016 · (Permalink)
I'm a 25 year old man and this is the best explanation of circumference and pi that I've ever seen. Thank you so much for this. Really wish I had this lesson years and years ago.
Instantcoffees · 2 points · Posted at 23:49:54 on January 9, 2016 · (Permalink)
Wait a minute. Math actually makes sense? They never told me this in high school!
boraxus · 2 points · Posted at 00:38:01 on January 10, 2016 · (Permalink)
My god. I am 39 years old and struggled with geometry in junior high/high school. A rectangle's area is the length times the height, therefor a square's area is either the height or the length squared. After seeing this, it is the first time I ever understood "(Pi)(r-squared)" and how it makes any sense. I've always just accepted it, and been frustrated not to know.
PartizanParticleCook · 2 points · Posted at 05:48:25 on January 10, 2016 · (Permalink)
Sorry you had a stink time with math but glad this helped
dgrant92- · 2 points · Posted at 01:55:01 on January 10, 2016 · (Permalink)
Wow too cool. I could have understood so much more with graphics like this to help my simple mind get it. (btw I still ended up aiming missiles by the stick...lol )
TrampyPizza77 · 3 points · Posted at 10:31:29 on January 9, 2016 · (Permalink)
THANK YOU SO MUCH. RADIANS NOW MAKE SENSE.
thebrose69 · 3 points · Posted at 08:31:45 on January 9, 2016 · (Permalink)
That is so incredibly confusing to me
PartizanParticleCook · 19 points · Posted at 08:36:47 on January 9, 2016 · (Permalink)
1 radian is the angle formed by wrapping the length of a circles radius around it's edge. Super duper useful for physics and maths.
barbiferousone · 3 points · Posted at 12:25:23 on January 9, 2016 · (Permalink)
TIL. thankyou, all of a sudden, a lightbulb has switched on.
tastes-like-chicken · 1 points · Posted at 18:49:56 on January 9, 2016 · (Permalink)
I got it up until the pi radians. Then I lost it
thebrose69 · -9 points · Posted at 08:38:02 on January 9, 2016 · (Permalink)
I mean I understood it, but my mind was ready to accept it, I guess. I was always just decent at math anyway
[deleted] · -6 points · Posted at 11:30:59 on January 9, 2016 · (Permalink)
[deleted]
laseralex · 7 points · Posted at 11:50:22 on January 9, 2016 · (Permalink)
Your mistake is converting Pi into a decimal value. Not only is that not necessary, it actually complicates things. Just leave it as Pi. Why? Because often another Pi will pop up in your equation, and you'll either cancel it or square it. It is easier to cancel or multiply if you keep it as "Pi", and it is also much easier to write the Pi symbol than to write out 3.14159 . . .
Hayarotle · 6 points · Posted at 11:46:18 on January 9, 2016 · (Permalink)
We just use Pi and fractions of Pi, which is pretty much what you're suggesting with redefining the radian as 1/3 pi. But having an unit angle equal to unit length in circle with unit radius is very useful.
[deleted] · -1 points · Posted at 12:02:35 on January 9, 2016 · (Permalink)
[deleted]
Hayarotle · 4 points · Posted at 12:13:13 on January 9, 2016 · (Permalink)
Here is a practical example.
Say you have a car with wheels of radius 0.5 m. The car is moving at a speed of 10 m/s. How fast is the wheel rotating?
With degrees, you gotta divide the car's speed by 2 Pi, divide by the radius (0,5 m) and multiply by 360. Try doing that.
With radians, you just divide by the radius! So, it is spinning at an angular velocity of 20 rad/s. Easy!
[deleted] · 2 points · Posted at 12:15:23 on January 9, 2016 · (Permalink)
Here's one advantage, if you define sin(x) and cos(x) in degrees. (e.g: sin(90)=1, cos(180)=-1,cos(270)=0...)
Then the derivative of sin(x) is (2pi/360)cos(x), and the derivative of cos(x) is -(2pi/360)sin(x)
On the other hand, if you define them in radians (e.g: sin(pi/2)=1, cos(pi)=-1, cos(3pi/2)=0...0
Then the derivative of sin(x) is cos(x) and the derivative of cos(x) is -sin(x)
aianus · 2 points · Posted at 12:15:49 on January 9, 2016 · (Permalink)
If given an angle in radians and the radius of the circle, then the arc length is exactly the angle times the radius.
Degrees are like inches and feet, they don't naturally relate to anything.
MindStalker · 1 points · Posted at 13:07:13 on January 9, 2016 · (Permalink)
Radians are the distance around your circle. How much rope do you need for this circle? You need 2piR. Don't convert to decimal ever until you absolutely need to. Think of pi as a unit like inches. So how much rope do you need to go around the circle 100 and a half times, 201piR. Had you converted in the previous step you would have a less accurate number now. Going around a circle a half is pi, a quarter is 1/2pi generally written as fraction instead of a decimal when going fraction ways around a circle.
lucasvb · 3 points · Posted at 11:57:20 on January 9, 2016 · (Permalink)*
The point is that we need an angle unit that is inherent to the circle. Radians do that.
But the fact there are 6.283185... radians in a circle doesn't matter. The number is not important, that's why we have a constant for it (2π = τ). We don't care about it.
What we would use most of the time is a ratio of that number, so τ/4 = 2π/4 = π/2 is a quarter of a circle, and so on. That means the constant makes it human-readable, and the fact we're using radians as a unit makes it mathematically sensible.
(By the way, before someone complains, radians ARE a unit. They're a dimensionless unit, but a unit as well. A degree is also a dimensionless unit which is 1/360 of the angle around a circle, as opposed to 1/2π around a circle.)
Cerxi · 1 points · Posted at 12:35:55 on January 9, 2016 · (Permalink)
Because part of the use of it is that it is equal to the radius. If you added 1/3pi to each radian, than near every use of a radian in your equasions is going to look like "r - 1/3pi". Plus, it makes the definition of a radian from "the length of the radius, wrapped around the edge" into "the length of the radius, plus one third of pi times itself, wrapped around the edge". Neither is elegant or especially useful.
[deleted] · 1 points · Posted at 13:07:53 on January 9, 2016 · (Permalink)
Woosh. Go back to 9th grade.
(Edit: I don't know whether it's taught in schools at that age, it was in mine)
KusanagiZerg · 1 points · Posted at 13:52:25 on January 9, 2016 · (Permalink)
I was never taught radians in high school hence my questions and confusion but it seems like asking things is against the spirit of /r/eli5 so nevermind.
barbiferousone · 1 points · Posted at 12:30:54 on January 9, 2016 · (Permalink)
isn't 2 x pi equal to 6.283185 ?
Kayyam · 2 points · Posted at 13:01:01 on January 9, 2016 · (Permalink)
No.
barbiferousone · 1 points · Posted at 13:07:51 on January 9, 2016 · (Permalink)
please explain, I'm genuinely not understanding this. my calculator gives an answer of 6.283185. thanks.
Kayyam · 2 points · Posted at 13:14:09 on January 9, 2016 · (Permalink)
2*Pi is approximately 6.283185. It's not equal to that. Because Pi is irrational and the sequence of numbers never ends nor repeats itself.
______DEADPOOL______ · 2 points · Posted at 12:20:02 on January 9, 2016 · (Permalink)
That is so rad
[deleted] · 1 points · Posted at 12:44:52 on January 9, 2016 · (Permalink)
Hey you! Presidential Candidate 2016!
______DEADPOOL______ · 2 points · Posted at 12:54:36 on January 9, 2016 · (Permalink)
I'm not Bernie Sanders, man.
absinthe-grey · 1 points · Posted at 11:15:17 on January 9, 2016 · (Permalink)
Rad.
AnEpiphanyTooLate · 1 points · Posted at 12:23:59 on January 9, 2016 · (Permalink)
Holy shit! Is there a website/subreddit that visualizes math/science topics like this?
mcfandrew · 1 points · Posted at 14:45:26 on January 9, 2016 · (Permalink)
/r/mathgifs
PM_ME_YOUR_NACHOS · 1 points · Posted at 12:44:45 on January 9, 2016 · (Permalink)
Is this how they find the precision in pi? I still struggle to find out how they find all the decimal of pi.
[deleted] · 2 points · Posted at 13:15:31 on January 9, 2016 · (Permalink)
Here's a few examples: http://www.wikihow.com/Calculate-Pi
The Taylor series is where i learned it: https://www.math.hmc.edu/funfacts/ffiles/30001.1-3.shtml
How pi has been calculated in the past is actually very interesting, https://en.wikipedia.org/wiki/Approximations_of_%CF%80 for a history and the different techniques used.
PartizanParticleCook · 1 points · Posted at 22:44:41 on January 9, 2016 · (Permalink)
It's incredibly hard to compute but basically you carry the division to as many decimal places as possible.
DopeyMcSnopey · 1 points · Posted at 12:55:28 on January 9, 2016 · (Permalink)
I don't know what to do with this information.
Awdayshus · 1 points · Posted at 12:55:40 on January 9, 2016 · (Permalink)
That's pretty rad.
Robborboy · 1 points · Posted at 12:58:49 on January 9, 2016 · (Permalink)
After watching this I feel owning a Geiger Counter is now more important than ever.
Oxford_karma · 1 points · Posted at 13:02:58 on January 9, 2016 · (Permalink)
Wow. I needed that like ten years ago
GeneralDisorder · 1 points · Posted at 13:04:32 on January 9, 2016 · (Permalink)
I remember learning about radians in probably trigonometry but was never told what it means. Just what the angle was in degrees.
Schootingstarr · 1 points · Posted at 13:13:48 on January 9, 2016 · (Permalink)
half the circumference of a circle is a pi-rad
yo-ho-ho and a bottle rum!
lastkajen · 1 points · Posted at 13:19:09 on January 9, 2016 · (Permalink)
That's rad
iWantedMVMOT · 1 points · Posted at 13:19:22 on January 9, 2016 · (Permalink)
Where was this when I needed it....
akhilleus650 · 1 points · Posted at 13:24:17 on January 9, 2016 · (Permalink)
Holy crap, nobody has ever told me this! Every one of my teachers has just told me there are 2pi rads per 360 degrees and made us learn by repetition. Thank you for this!
WHERESMYNAMEGO · 1 points · Posted at 13:45:25 on January 9, 2016 · (Permalink)
That's rad
irascibleuserblame · 1 points · Posted at 13:50:01 on January 9, 2016 · (Permalink)
Hehe... pirate
Kierkin · 1 points · Posted at 13:53:44 on January 9, 2016 · (Permalink)
1 Rad
Sooap · 1 points · Posted at 13:55:34 on January 9, 2016 · (Permalink)
Where has this been my whole life.
Kaze47 · 1 points · Posted at 14:01:09 on January 9, 2016 · (Permalink)
Wouldn't it be 3Pi?
ProfessorChaos5049 · 1 points · Posted at 14:04:35 on January 9, 2016 · (Permalink)
All my years of math classes and this gif did a better job explaining what a radian is than anything I've ever had
[deleted] · 1 points · Posted at 14:05:30 on January 9, 2016 · (Permalink)
That was some Sesame Street level visualization, right there. Whoever made that did very well.
[deleted] · 1 points · Posted at 14:06:54 on January 9, 2016 · (Permalink)
Pretty rad
unassigned_username · 1 points · Posted at 14:10:38 on January 9, 2016 · (Permalink)
https://en.wikipedia.org/wiki/Gradian My father told me about this when he was still working as a geodesist (he's in pension now).
n_mca · 1 points · Posted at 14:14:17 on January 9, 2016 · (Permalink)
This doesn't focus enough on the most important point by far, that the arc length is r*theta.
blakfeld · 1 points · Posted at 14:14:57 on January 9, 2016 · (Permalink)
Holy fuck everything just snapped into place
user5577 · 1 points · Posted at 14:17:44 on January 9, 2016 · (Permalink)
The circumference of a circle is 2pir ... so is a rad just that relationship quantified
greyttast · 1 points · Posted at 14:22:21 on January 9, 2016 · (Permalink)
.
you_get_CMV_delta · 2 points · Posted at 14:25:29 on January 9, 2016 · (Permalink)
That is a great point. I had not thought about the matter that way before.
greyttast · 1 points · Posted at 14:27:26 on January 9, 2016 · (Permalink)
...I had hoped no one would notice my period.
I used that to save this comment. I'm fully aware of reddit's save feature, but windows phones are literally the foul excrement of Satan himself, and there is no comment save feature on my app.
Braedoktor · 1 points · Posted at 14:26:35 on January 9, 2016 · (Permalink)
That's rad.
doogles · 1 points · Posted at 14:27:44 on January 9, 2016 · (Permalink)
2 Pi rads walk into a bar...
i_spot_ads · 1 points · Posted at 14:31:43 on January 9, 2016 · (Permalink)
ooohhhkaaayy now i see
luketheduke03 · 1 points · Posted at 14:39:48 on January 9, 2016 · (Permalink)
Wow that's pretty rad
duhzmin · 1 points · Posted at 14:47:20 on January 9, 2016 · (Permalink)
If there a sub Reddit dedicated to animations like this?
PartizanParticleCook · 1 points · Posted at 22:37:01 on January 9, 2016 · (Permalink)
I believe /r/educationalgifs has something that is similar
jvkeizer · 1 points · Posted at 14:51:08 on January 9, 2016 · (Permalink)
If only I had seen that 3 years ago when trying to figure out sin, cos and all that other shit
Truffle_Shuffle_85 · 1 points · Posted at 14:54:45 on January 9, 2016 · (Permalink)
I now understand rads, thanks.
marijn198 · 1 points · Posted at 14:59:14 on January 9, 2016 · (Permalink)
REALLY? Fucking 2 times gold for a gif that has been posted a million times?
dylansesco · 1 points · Posted at 15:06:32 on January 9, 2016 · (Permalink)
Yep, those are shapes and stuff.
Fatburg · 1 points · Posted at 15:07:39 on January 9, 2016 · (Permalink)
Damn, I wish I'd had this in high school.
blacklab · 1 points · Posted at 15:08:13 on January 9, 2016 · (Permalink)
Whoa.
PetrRabbit · 1 points · Posted at 15:09:33 on January 9, 2016 · (Permalink)
TIL that pi is an amount of radians.
loombo · 1 points · Posted at 15:10:00 on January 9, 2016 · (Permalink)
Haha that's pretty rad
uncletugboat · 1 points · Posted at 15:13:11 on January 9, 2016 · (Permalink)
Such a simple post could've replaced an entire week of school.
Shadow_Banned_Why · 1 points · Posted at 15:17:09 on January 9, 2016 · (Permalink)
Thanks for the gif
myhf · 1 points · Posted at 15:19:12 on January 9, 2016 · (Permalink)
rad
Zadoose · 1 points · Posted at 15:23:57 on January 9, 2016 · (Permalink)
holy shit i never understood the meaning of that and have been using pi and rad for years and only til now do i know where this comes from, that was amazing
wedontlikespaces · 1 points · Posted at 15:25:27 on January 9, 2016 · (Permalink)
In 2d graphics programing there is no circle command, only lines and arcs, so to draw a circle you just tell the computer to draw an arc with an angle of Pi x 2.
I never understood how that worked until just now, thanks!
steveCharlie · 1 points · Posted at 15:30:37 on January 9, 2016 · (Permalink)
That's so rad.
DarkDarkness · 1 points · Posted at 15:30:51 on January 9, 2016 · (Permalink)
I never wish to get remotely close to having to learn stuff like this
capt_clark · 1 points · Posted at 15:31:04 on January 9, 2016 · (Permalink)
Yo, piRad has me pretty incensed right now.
nohiddenmeaning · 1 points · Posted at 15:31:13 on January 9, 2016 · (Permalink)
Is that some sort of math joke where a half circle equals one pirate?
dagormz · 1 points · Posted at 15:36:25 on January 9, 2016 · (Permalink)
Shouldn't that last little bit on the first half be pi / 3 ?
PartizanParticleCook · 1 points · Posted at 22:35:33 on January 9, 2016 · (Permalink)
Nope, pi is that little bit and the others. 180 degrees is made up of 3 radius lengths wrapped round the circles arc + a little bit more. That little bit more is 1 radius length * 0.1415926535897..... and so on.
thisisandy90 · 1 points · Posted at 15:42:47 on January 9, 2016 · (Permalink)
That was rad
PotatoMussab · 1 points · Posted at 15:54:50 on January 9, 2016 · (Permalink)
You got gold. You should edit your comment as follows:
EDIT: This blew up so fast. EDIT 2: Thanks for the gold.
[deleted] · 1 points · Posted at 15:55:05 on January 9, 2016 · (Permalink)
Thanks! That made it make a lot of sense.
Now I have an odd craving for pizza all of a sudden.
ItsTimeDrFreeman · 1 points · Posted at 15:56:36 on January 9, 2016 · (Permalink)
Hey this gif is pretty...Rad
SMEGMA_IN_MY_TEETH · 1 points · Posted at 16:00:58 on January 9, 2016 · (Permalink)
That gif was rad.
sephtis · 1 points · Posted at 16:02:12 on January 9, 2016 · (Permalink)
Pi is so weird. Coming from a guy who isn't a fan of maths.
Doctor_John_Watson · 1 points · Posted at 16:03:09 on January 9, 2016 · (Permalink)
Wow. Who works this shit out? Especially Pi which only ever has an approximate value. Oh yeh, some stoned beardy togaGreeks. Anybody know what exactly they smoked back then? I want some so I can figure out all kinds of unanswered shit. Wow, some kids just built a little snowman outside my coffee shop. Oops, sorry, #shortAttentionSpan
Horse_Sized_Duck_ · 1 points · Posted at 16:04:41 on January 9, 2016 · (Permalink)
But surely there'd have to be a number of how many radians are in pi, right? It can't go on indefinitely.. Can it? For the fourth piece of that gif once r starts going around the circle to make one pi, if it is a definitive space needed for what is supposed to be the 3+.1415..... How is it possible that to find the length it is all repeating?
PartizanParticleCook · 1 points · Posted at 22:33:04 on January 9, 2016 · (Permalink)
If you can work that out you will get a butt-load of money as it is crazy hard to calulate, those these guys did 12 trillion and it took them 94 days of computation to do so.
It is not definite that it never repeats itself but proving that is hard as hell. In this case, you'd have to get to the infinite digit to prove it never repeats and that is impossible due to infinity being larger than everything, meaning that as soon as you get to the 'last' digit there will be even more.
Prtyvacant · 1 points · Posted at 16:08:26 on January 9, 2016 · (Permalink)
I get the 3 rads that make up 1 pi rad, but what's the measurement of that little remainder? If it isn't obvious, I'm not a STEM person.
PartizanParticleCook · 2 points · Posted at 22:28:31 on January 9, 2016 · (Permalink)
Hey non-STEM person, 3 rads make up very very nearly a full half (180 degrees) of a circle.
The little bit left over is the fractional part of Pi and that is 0.14159265358979... * 1 radius length. This fraction is flipping annoying as it never repeats itself (as far as we know) and is only needed to make the whole thing work.
AntennasAreMagic · 1 points · Posted at 16:20:20 on January 9, 2016 · (Permalink)
What the...
How did I never realize that before...So simple, so elegant!
Thanks!
[deleted] · 1 points · Posted at 16:21:08 on January 9, 2016 · (Permalink)
That's pretty rad
DJCatfoodFace · 1 points · Posted at 16:25:48 on January 9, 2016 · (Permalink)
Rad
blore40 · 1 points · Posted at 16:28:14 on January 9, 2016 · (Permalink)
So every pie is 2pi?
realfoodman · 1 points · Posted at 16:31:33 on January 9, 2016 · (Permalink)
2 rad 4 math.
dan_nad · 1 points · Posted at 16:33:24 on January 9, 2016 · (Permalink)
I've no idea how I never made this connection. Amazing.
eggnaramoose · 1 points · Posted at 16:33:55 on January 9, 2016 · (Permalink)
Pretty rad
savethetriffids · 1 points · Posted at 16:40:42 on January 9, 2016 · (Permalink)
Amazing. Where was this when I was in grade 12? Thanks!
[deleted] · 1 points · Posted at 16:46:42 on January 9, 2016 · (Permalink)
Ooooooooohhhhhh
This really would have helped me in high school.
Brooklyyyn23 · 1 points · Posted at 16:48:45 on January 9, 2016 · (Permalink)
Oooooooooooooooo!
sonicandfffan · 1 points · Posted at 16:59:53 on January 9, 2016 · (Permalink)
And there was me thinking rads were what you got for standing in poop in fallout
80Eight · 1 points · Posted at 17:01:13 on January 9, 2016 · (Permalink)
If PI Rad hadn't jumped out of no where I might understand it...
Where did that come from? What's that tiny slice called? Is a half a sphere a rad or half a circle... Is it 3.14 of a circle a PI Rad? Is that .14 the tiny amount and all the others are 1.00?
PartizanParticleCook · 2 points · Posted at 22:24:30 on January 9, 2016 · (Permalink)
So one radian is formed by wrapping 1 radius length about the edge of a circle. 3 of these wrapped together gives you a 3 radian arc.
However, there is a little piece left and that little bit is the fractional element of Pi. So 180 degrees is half a circle which is 3 radians plus a little bit extra.
[deleted] · 1 points · Posted at 17:02:09 on January 9, 2016 · (Permalink)
As someone who has the mathematical abilities of a toddler, this gif confused the ever living shit out of me
pipnewman · 1 points · Posted at 17:03:29 on January 9, 2016 · (Permalink)
Whoa!
theacorneater · 1 points · Posted at 17:07:39 on January 9, 2016 · (Permalink)
this pi value is mysterious and magical
dodgeunhappiness · 1 points · Posted at 17:08:12 on January 9, 2016 · (Permalink)
Why the hell nobody taught me radians this way ?! I spent hours memorising an obvious thing.
majornerd · 1 points · Posted at 17:12:45 on January 9, 2016 · (Permalink)
Ha! First time that made sense. Thank you.
dancingbanana123 · 1 points · Posted at 17:16:02 on January 9, 2016 · (Permalink)
That's pretty rad
ijustwantanfingname · 1 points · Posted at 17:16:11 on January 9, 2016 · (Permalink)
....why the hell didn't my geometry teacher just tell us that in the first place? That makes so much sense.
Alyybaba · 1 points · Posted at 17:25:06 on January 9, 2016 · (Permalink)
holy shit
daintydramatist · 1 points · Posted at 17:32:29 on January 9, 2016 · (Permalink)
Great stuff! How do you produce the 2D gifs? They're great!
kabuto_mushi · 1 points · Posted at 17:36:18 on January 9, 2016 · (Permalink)
It can't be that simple... ? So pi in rad is just "the little bit of circumference left after 3 rad"?
slackerboyfx · 1 points · Posted at 17:59:27 on January 9, 2016 · (Permalink)
pi rad appears to be 1/2 of the circumference. its 3.14... rads
PartizanParticleCook · 1 points · Posted at 22:22:30 on January 9, 2016 · (Permalink)
Pi is 3 radii + that little bit left, yes.
geocitiesuser · 1 points · Posted at 17:42:28 on January 9, 2016 · (Permalink)
Where was this gif when I was in college?
cdawgtv2 · 1 points · Posted at 17:46:46 on January 9, 2016 · (Permalink)
I think I just leveled up.
ghillerd · 242 points · Posted at 11:16:04 on January 9, 2016 · (Permalink)
it's worth noting that radians aren't arbitrary - an angle of 1 radian is defined by the properties of a circle rather than being an arbitrary number of slices.
understated_panda · 4 points · Posted at 12:55:03 on January 9, 2016 · (Permalink)
Going even further down the rabbit hole, some would argue that the definition of pi is some what arbitrary/wrong: https://youtu.be/jG7vhMMXagQ
ghillerd · 62 points · Posted at 13:30:46 on January 9, 2016 · (Permalink)
well, the definition of pi as 'the number of radians in a straight line' or 'the ratio between a circle's circumference and diameter' is correct and absolutely true, so the way we define pi isn't 'arbitrary' or 'wrong'. in that video, Vihart is arguing that its use is less intuitive or practical than the use of tau. deciding whether you want to use pi, tau, or some other constant like pi/2 or pi/12 is the arbitrary part. you could argue that pi/12 (let's call it mu) is a good one because then you have 24mu in a circle, which divides up very easily into subsections (1/2, 1/3, 1/4, 1/6, 1/8, 1/12, 1/24) of the circle without having to use fractions, which some people prefer for aesthetic reasons. tau on the other hand lets you use the fraction of tau as the fraction of the circle you're dealing with. pi, also, comes up in a lot of equations without a factor of 2 (for example, the area of a circle) and is neater in those instances. so they both have advantages and disadvantages.
UntamedOne · 3 points · Posted at 17:51:53 on January 9, 2016 · (Permalink)
I'd guess that pi was preferred by people that measured diameters by hand to use in calculations. Tau is like the idealized pure version where no physical measurements will need to be done because you just specify the radius.
ghillerd · 1 points · Posted at 18:05:40 on January 9, 2016 · (Permalink)
Yeah exactly, so it more depends on what you're doing that anything else. I like tau because of the whole fractions of a circle thing, but if I've measured a diameter, I'm not going to then divide it in half just for the sake of using it.
zacker150 · -1 points · Posted at 19:37:39 on January 9, 2016 · (Permalink)
Pi is arguably the more pure version because of how often it comes up in mathematics. For an example, the integral of the Gaussian is the square-root of pi.
[deleted] · 0 points · Posted at 18:29:32 on January 9, 2016 · (Permalink)*
[deleted]
algag · 1 points · Posted at 18:51:45 on January 9, 2016 · (Permalink)
I don't think you know what diameter means. Lol jk. But for real, it just depends on if you consider the diameter or the radius more important. I could say that that I prefer tau because "ratio of radius to the circumference" is more intuitive than " ratio of half the diameter to the circumference "
ghillerd · 1 points · Posted at 19:10:56 on January 9, 2016 · (Permalink)
Ratio of radius to diameter is 2. Ratio of diameter to circumference is pi. Ratio of radius to circumference is tau.
HAHA_goats · 12 points · Posted at 13:55:58 on January 9, 2016 · (Permalink)
2π=τ?
Pfft. That's absurd. τ looks like a half a π, but it's supposed to be 2*π. Thus, a contradiction. QED, mofos!
user_82650 · 13 points · Posted at 14:47:07 on January 9, 2016 · (Permalink)
You can see τ and π as the bottom part of a fraction. Then it looks like "divided by 1" and "divided by 2".
INTERNET_RETARDATION · 2 points · Posted at 15:13:54 on January 9, 2016 · (Permalink)
/r/shittyaskscience
[deleted] · 44 points · Posted at 13:29:34 on January 9, 2016 · (Permalink)
Ah yes. Tauism. I've heard of that religion.
Amablue · 7 points · Posted at 15:23:52 on January 9, 2016 · (Permalink)
It's a shame it never caught on, it's better than pi in just about every way.
FkIForgotMyPassword · 10 points · Posted at 17:04:59 on January 9, 2016 · (Permalink)
The main reason people think that this is the case is because there are videos and infographics and everything made by people who want to push for tau, while not many serious people actually care to defend pi because of how futile it is.
I suggest you read a well-written answer to all of this noise about tau, like http://www.thepimanifesto.com/ for instance. I'd be surprised if, after reading that, you still think tau is better than pi in "just about every way".
Amablue · 5 points · Posted at 17:35:47 on January 9, 2016 · (Permalink)*
That page is not very convincing. Tau is still clearly better to me.
The main points seem to be (1) that basing our constant on the diameter makes more sense because it's easy to measure and (2) that just as many equations are made simpler by pi and that the equations that tau makes simpler were carefully selected.
I disagree with both of these points. In math, we don't measure circles, we create them. A unit circle is a circle with a radius of 1. We do all kinds of math based on a unit circle. The radius is the fundamental value that describes the circle. We should use that when making our definitions. Arbitrarily switching between radius for some thing and diameters for others only confuses the relationships between things.
The page uses as an example the area of a unit circle. They claim that tau is only more intuitive measuring angles while pi is much better for areas. This is silly, of course tau is better for angles, that's what it's measuring. They claim as an example that the area of a unit circle, pi, is beautiful and simple and thus a point in pi's favor. The result of pi is simpler, but it's not better. You've lost the relationship between the angle and the area. When you express the area in terms of tau the relationship between angle and area is preserved.
Let me expand on that a bit: Consider the case where you're trying to find the area of a circle by integration. You have the equation ∫ τ r dr, which we can integrate to find τ r2 / 2. That extra division by 2 isn't arbitrary - it's there because we have an integral. Its part of the relationship that we obscure when we use pi.
Most of the rest of the arguments are variations on the area argument - that some equations work out 'prettier' when you use pi instead of tau. The main difference between the two constants is that you end up adding or removing a 2 somewhere in your equations. In the case of tau though, those 2's are meaningful and help demonstrate relationships between various areas of math. In the case of pi, they're just thrown in and meaning is lost. It's not about what gives us simpler equations, it's about what gives us equations that demonstrate relationships and express the most meaning.
FkIForgotMyPassword · 2 points · Posted at 18:24:51 on January 9, 2016 · (Permalink)
I'm not sure I agree with this, considering that I (and probably a good number of mathematicians) don't really do either, but regardless, when he makes this point, he's responding to a part of the Tau manifesto that discusses the genesis of Pi in ancient Greece, and clearly Greek mathematicians were interested in measuring things (including "circles", e.g. here).
I don't get where you're going with that. If you have two quantities, one of which equal to tau=2pi, one of which equal to tau/2=pi, and there is a way to go from the first to the second to "justify" the factor 1/2 in tau/2 in the second quantity, then it also explains the factor 2 in the 2pi of the first equation. It's just a matter of point of views.
All of that only holds based on the assumption that tau is a better constant. You're not adding another argument in favor of tau by saying that: you're just restating that you think it is better.
Well, I find more meaning in writing the Gaussian integral with pi than with tau. Same things with the links between the Gamma function and pi or tau. Same with Euler's identity (I mean, "exp(i*pi)=-1, therefore exp(2*i*pi)=(-1)2" is nice, while you lose something if you try to start from tau by saying "exp(i*tau)=1, therefore exp(i*tau/2)=±11/2). And I really think that having simpler expressions is a good thing: readability is probably just as meaningful as having the best content, if you're trying to teach math.
Amablue · -1 points · Posted at 18:55:37 on January 9, 2016 · (Permalink)
The integral of
xis1/2 x^2. Whenever you see that form come up in an equation, that's a big hint that you're looking at an integral.There was this great moment for example when I took both physics and calc in college where we were looking at an equation for moving objects,
y = 1/2 a t^2 + vt + x, and I thought to myself "Man, that really looks like an integral". Just a few days later, we did the integral that produces that equation, which connected those two concepts in my mind.The form of the equation can be used to carry meaning. It demonstrates the relationship. The 1/2 a t2 is an integral, which is why it has the same form as 1/2 τ r2. That 1/2 isn't arbitrary, and it's not better to just remove it. It connects the concept of the area of a circle to the concept of the integral of x.
I'll post more later, I have to head out and take care of an errand.
exploding_cat_wizard · 2 points · Posted at 18:09:38 on January 9, 2016 · (Permalink)
It's not worth the bother of changing by about a factor 109, though.
TAU_doesnt_equal_2PI · 1 points · Posted at 19:50:14 on January 9, 2016 · (Permalink)
[deleted] · 33 points · Posted at 14:32:23 on January 9, 2016 · (Permalink)
Let me be blunt: no one who does actual math cares about tau vs pi. People who care about tau are displayed on the left in this comic.
YoungIgnorant · 3 points · Posted at 15:57:13 on January 9, 2016 · (Permalink)
You do know Vi Hart is a serious mathematician, right? I think most mathematicians would agree that Tau would probably be the better fundamental constant, but don't make it their vendetta. However, it would make teaching trigonometry so much easier, that I think math educators should care a ton about the distinction.
[deleted] · 14 points · Posted at 16:11:35 on January 9, 2016 · (Permalink)*
What? According to herself she's a "recreational mathemusician". I'm talking about actual mathematicians, you know, the ones who work in a university or a research institute. As far as I'm aware, she isn't. I'm not saying I don't like her videos or anything -- but she isn't a serious mathematician anymore than the guys from mythbusters are serious physicists or serious chemists.
I'm a mathematician (I work at a university and I'm paid in part to produce mathematics research, something that occupies a very large part of my awake time, in case I really need to make clear what I mean by that...), and I don't think that. The topic has come up a few times talking with my colleagues, and no, they simply think (like me) that the whole tau thing is silly, that it wouldn't change anything at all to mathematics, and it's not worth wasting time about. It's my impression that it's the general sentiment among mathematicians everywhere, though there are probably exceptions somewhere.
It's not even clear that it would make teaching trig any easier. If you want, here's a Q&A at matheducators.SE, it's mostly people with actual interest in math education (as opposed to armchair math educators). Here's the pi manifesto too. As for myself, I simply don't care. Pi is the standard, and the minute benefit (if any!) gained by changing are not worth the notational upheaval.
DanielMcLaury · -1 points · Posted at 00:22:41 on January 10, 2016 · (Permalink)
She publishes regularly, which seems substantially more relevant than who signs her paychecks. You wouldn't say James Simons isn't a mathematician because he makes his money at a hedge fund.
TheFourFingeredPig · 3 points · Posted at 20:07:24 on January 9, 2016 · (Permalink)
When I was in high-school and didn't know any higher math, I thought tau was the shit -- I told everybody about it. Now I'm currently in my senior year of an undergrad math degree, and it's honestly a meaningless debate. If you tried to bring up this debate in the math department, you'll get eyes rolled at you.
I'm not trying to discredit those who have sparked this debate, because it's good that math is getting a little bit of spotlight in popular culture. I probably wouldn't have decided to major in math had I not been exposed to popular math first.
As for the education aspect of it, mathematics is as much tradition as it is rigor. A good mathematics educator, in my opinion, would teach the history of mathematics along with the lesson plan, particularly in a geometry class. Using pi over tau is far from the problem why students have trouble understanding trigonometry. The problem is that many good educators do not bother to go into K-12 education (at least in the US), because the US does not respect the teaching profession.
FkIForgotMyPassword · 5 points · Posted at 17:20:23 on January 9, 2016 · (Permalink)
I consider myself a young but somewhat serious mathematician (published in several good journals in my field of study), and I disagree. Of course, if tau had been the constant forever, and people were pushing to make pi the new constant, I'd find it pointless too. But still, I prefer pi over tau regardless of the history of things.
People who advocate for tau tend to pick examples that they like, mostly from very basic math. That makes sense because they want to reach a greater public, but it's also a bias as their arguments hold much stronger there than if you also consider broader topics (series, probabilities etc). http://www.thepimanifesto.com/ summarizes that pretty well.
But to be fair, one of my major concerns is that when manipulating pi, you encounter a lot of nπ, 2π, 2π/3, π, π/2, π/3, π/4, π/6, π2/6 etc. Write these expressions with tau instead, and you get nτ/2, τ, τ/3, τ/2, τ/4, τ/6, τ/8, τ/12, τ2/24. Out of these common examples, only two are (slightly) simpler with tau: τ instead of 2π, and τ/3 instead of 2π/3. However, most are more annoying to write with tau, including in some cases having to write a fraction where there wasn't one when we used pi. Of course, people doing math in different domains are going to encounter all of these expressions with varying frequencies, but in my experience, the only domains in which you see "2π" so often that abbreviating it into "τ" counter-balances the scenarios in which using pi makes an expression simpler to write (and potentially removes a fraction) is when you're working with Fourier transforms, or in general when you use exp(2πi) a lot, and in that case, your meaningful constant isn't 2π, but 2πi, meaning that tau isn't the appropriate choice here either.
narp7 · 5 points · Posted at 17:15:59 on January 9, 2016 · (Permalink)
This doesn't show that there's anything wrong with pi, or that it's arbitrary. Pi is not an arbitrary value at all. To claim that it's arbitrary is demonstrably false.
This is just someone who is bad at math ranting because there are 2pi in a pie and not one, as someone with no mathematical background at all would guess.
Seriously, she bakes a pie and then is upset when 1/4 of the pie, is not 1/4 pi radians. Well no shit. No one decided what a radian was. That's the natural unit!
Basically, this video is the dumbest shit I've seen all day. It's a video by ignorant people, for ignorant people. It's like a circlejerk of people celebrating how bad they are at math, then trying to say that because they don't understand it, it doesn't make sense.
There is nothing wrong with the concept of pi. You just can't assume that there is 1pi in a cherry pie. I'm sorry, but math is not based around the convenience of cherry pies.
Sully800 · 1 points · Posted at 21:02:44 on January 9, 2016 · (Permalink)
She's a mathematician, she understands the principles just fine. Vihart is proposing that tau is better than pi, because many people find it easier and more intuitive to learn. Half a circle is 1/2 tau, very straight forward.
Using pi as the basis is because humans started with physical round objects and then created mathematics to suit. You can measure the diameter and the circumference of a pipe, and therefore you can determine the ratio pi. However, if we started with mathematics as the basis there is no doubt tau would be the logical choice since the radius of the circle is the primary feature and used much more frequently throughout math and engineering.
ivalm · 2 points · Posted at 21:42:34 on January 9, 2016 · (Permalink)
VI Hart is a YouTube educator, not a mathematician. She hasn't done much meaningful mathematics research, heck, she only studies as an undergrad. As someone coming from physics (as in science, not an undergrad taking classes), and having worked and know people who work in theory (again, as in science, not cool YouTube demonstrations for general audience) I really don't know any serious person who has a preference for tau over pi. The entire discussion is a joke. They are equivalent and since pi has been around longer switching from it would just introduce unnecessary confusion.
Sully800 · 1 points · Posted at 01:51:15 on January 10, 2016 · (Permalink)
Completely agreed that switching from pi to tau would be a difficult process and not worthwhile, but I definitely think using tau would make trig easier for the average student.
CrabbyBlueberry · 2 points · Posted at 18:13:40 on January 9, 2016 · (Permalink)
For every situation where I have to use 2pi, there's another situation where you have to use tau/2.
Thue · 1 points · Posted at 16:56:15 on January 9, 2016 · (Permalink)
lol :)
[deleted] · 71 points · Posted at 11:58:19 on January 9, 2016 · (Permalink)*
[deleted]
AyeBraine · 21 points · Posted at 12:30:47 on January 9, 2016 · (Permalink)
Soviet army used 6000 standard. Russian Wiki says it's for the quickest divisibility and for quickly estimating angles in mils in the field directly from distances in your head. Then, if you want to raise the precision for particular tasks, you throw in a 5% offset. The traditional military name for this unit is "thousandth" (тысячная).
[deleted] · 1 points · Posted at 19:28:13 on January 9, 2016 · (Permalink)
Tisyachnaya
ShroudedSciuridae · 20 points · Posted at 13:52:40 on January 9, 2016 · (Permalink)
Can confirm American military also uses mils
Harbingerx81 · 1 points · Posted at 20:48:18 on January 9, 2016 · (Permalink)
Has to scroll down a long way to find mils mentioned...I spent some time doing survey for the artilley...Loved the fact that the main thing I surveyed for was radar that only needed to be roughly sighted in, considering that our measurements were down to .05 mils (less than .003 degrees).
zilti · 11 points · Posted at 14:14:54 on January 9, 2016 · (Permalink)
We use 6400 in the Swiss military as well, it's called "Artilleriepromille" (artillery per-mille)
Source: am anti-air-artillerist
My_usrname_of_choice · 2 points · Posted at 18:27:48 on January 9, 2016 · (Permalink)
Holy shit, "mils" are "miliradians"?
Just yesterday I was wondering why we used such a fucked up arbitrary segmentation of a circle and didn't use decimals of degrees. Now I know it isn't arbitrary. Wow.
bejean · 1 points · Posted at 15:35:44 on January 9, 2016 · (Permalink)
Mils are great for optics because of the small angle approximation: for very small x in radians, sin(x) ~= x.
If you have a scope marked in mils and you see and adult that is 2 mils tall in your scope, you can estimate that they are a kilometer away. Sin(.0002) ~= .0002 = height of person/distance, and adults are ~2m tall.
KuntaStillSingle · 1 points · Posted at 16:33:42 on January 9, 2016 · (Permalink)
This won't work, adjusting left or right is going to change the azimuth to the target less then that, and it will also change the range some.
Think of a circle, and the point you hit is on the circle. If the point you intend to hit is 100 meters to the right of it, it may be the same distance as 10m on the circle, but it doesn't follow the circle, the new point is either ahead of or behind it, depending on the perspective of the observer.
Even if it was that simple nobody would ever do it because they don't want to be the guy to say 'ah forget a new firing solution we can just fire the same mission again but adjust the deflection by 10m' because he is the guy who is going to be in deep shit if the round hits a walmart parking lot.
NotActuallyAWookiee · 1 points · Posted at 21:35:54 on January 9, 2016 · (Permalink)
I have a Mils compass. Wasn't aware of the specific attributes you've described here. I just thought it meant you didn't have to talk in fractions so soon!
jaredjeya · 32 points · Posted at 11:40:23 on January 9, 2016 · (Permalink)
I should add that the Radian is the natural unit of angles - if you use degrees, you'll get factors of 360/2π (or its reciprocal) everywhere, for example in calculus. They are the only non-arbitrary unit.
It's the ratio of the length around the arc, to the radius, for a given segment. Since a circle has a circumference of 2πr, you get 2π radians in a circle.
wolfkeeper · 4 points · Posted at 15:56:31 on January 9, 2016 · (Permalink)
Really, tau (2 Pi) is the most natural measure for the total angle in a circle.
Mahou · 3 points · Posted at 18:22:03 on January 9, 2016 · (Permalink)
Youtube vihart Pi Is (still) Wrong.
jellyman93 · 1 points · Posted at 22:28:38 on January 9, 2016 · (Permalink)
Really, 1 is the most natural measure of the total measure of an angle. It's not reliant on Euclidean geometry like radians are.
wolfkeeper · 1 points · Posted at 00:29:26 on January 10, 2016 · (Permalink)
Yes, that's also valid and called a turn, but how do you get from turns to radians?
jellyman93 · 1 points · Posted at 06:04:13 on January 10, 2016 · (Permalink)
Multiply by the circumference of the unit circle?
wolfkeeper · 1 points · Posted at 13:30:20 on January 10, 2016 · (Permalink)
Which is 2 Pi, also known as 'tau'.
jellyman93 · 1 points · Posted at 20:21:11 on January 10, 2016 · (Permalink)
Yeah, in Euclidean space it is.
wolfkeeper · 1 points · Posted at 20:52:05 on January 10, 2016 · (Permalink)
Actually in any differentiable space.
jellyman93 · 1 points · Posted at 21:13:27 on January 10, 2016 · (Permalink)
Really? Why is that?
jellyman93 · 1 points · Posted at 21:18:28 on January 10, 2016 · (Permalink)
I'm not seeing it. Surely hyperbolic planes are differentiable spaces?
And isn't the circumference only 2pir as r-> 0 (in hyperbolic)?
wolfkeeper · 1 points · Posted at 21:31:00 on January 10, 2016 · (Permalink)
yup. it tends to 2pi/r as r->0 in all differentiable spaces.
In fact we don't live in euclidean space anyway
jatheist · 1 points · Posted at 16:08:35 on January 9, 2016 · (Permalink)
A million times yes. I'm a math guy, but the unit circle always gave me problems. Just use tau!
fnybny · -1 points · Posted at 19:19:39 on January 9, 2016 · (Permalink)
Tau is not natural
wolfkeeper · 1 points · Posted at 00:38:32 on January 10, 2016 · (Permalink)
Well,
eitau = 1
is an identity, which are pretty natural things in mathematics.
fnybny · 1 points · Posted at 00:49:57 on January 10, 2016 · (Permalink)
What do you have against the additive identity
wolfkeeper · 1 points · Posted at 01:00:27 on January 10, 2016 · (Permalink)
Which particular additive identity?
0 + tau = 0
in angular terms.
fnybny · 1 points · Posted at 01:04:58 on January 10, 2016 · (Permalink)
The additive identify over the field of complex numbers... There is only one identity given a field and a well defined operation therein.
[deleted] · 5 points · Posted at 12:11:49 on January 9, 2016 · (Permalink)
Mils are also common in some militaries https://en.wikipedia.org/wiki/Angular_mil
GwtBc · 2 points · Posted at 13:27:16 on January 9, 2016 · (Permalink)
Radians aren't really 'arbitrary' though...
PayData · 2 points · Posted at 03:51:23 on January 10, 2016 · (Permalink)
there are tau rads in a circle! Down with pi! Up with the Tau Hegemony!
ktisis · 1 points · Posted at 07:47:52 on January 10, 2016 · (Permalink)
Why is this the only comment about tau?? Pi is a pedagogical disaster! We need more tau in math education!
[deleted] · 1 points · Posted at 13:25:22 on January 9, 2016 · (Permalink)
The Australian army uses mils. 6400 mils in a circle
My_usrname_of_choice · 1 points · Posted at 18:29:43 on January 9, 2016 · (Permalink)
I just read elsewhere that mils are miliradians. Mind blown.
prikaz_da · 1 points · Posted at 13:44:58 on January 9, 2016 · (Permalink)
Gradians, you mean. That's just an abbreviation, as far as I'm aware.
[deleted] · 1 points · Posted at 14:02:20 on January 9, 2016 · (Permalink)
[deleted]
My_usrname_of_choice · 1 points · Posted at 18:30:32 on January 9, 2016 · (Permalink)*
Mils= miliradians
I'm doing a service to point this out every time I see it in this thread. I only just learned this.
[deleted] · 1 points · Posted at 14:07:55 on January 9, 2016 · (Permalink)
It's not arbitrary at all. 360 is divisible by many numbers. That's why it was chosen.
stabinthedark_ · 1 points · Posted at 14:13:05 on January 9, 2016 · (Permalink)
Minute of angle is another one
nashvortex · 1 points · Posted at 14:13:52 on January 9, 2016 · (Permalink)
The radian is of course not arbitrary. It is actually a rather natural way to measure the curvature of things which does not vary with the size of the thing being measured.
prtierne · 1 points · Posted at 14:27:20 on January 9, 2016 · (Permalink)
What!? Not allowed
Redowadoer · 1 points · Posted at 14:34:13 on January 9, 2016 · (Permalink)
Radians are the only non-arbitrary way.
TeaRex14 · 1 points · Posted at 15:14:12 on January 9, 2016 · (Permalink)
Oh neat I always wonder grads where on my calculator when I switched from degrees to Radians
Qwop_till_you_drop · 1 points · Posted at 15:27:17 on January 9, 2016 · (Permalink)
What uses do these other measurements have over degrees?
OhhhSnooki · 1 points · Posted at 15:45:03 on January 9, 2016 · (Permalink)
Radians are not arbitrary.
[deleted] · 1 points · Posted at 15:45:39 on January 9, 2016 · (Permalink)
Ah perhaps the grad is what I know some of the iron mines in Sweden use. Gives a 400degree circle?
WhyattThrash · 1 points · Posted at 15:55:56 on January 9, 2016 · (Permalink)
Radians are also used a lot in programming.
kortez84 · 1 points · Posted at 15:59:00 on January 9, 2016 · (Permalink)
And (I have been told) that 360 was chosen because there are so many dang ways to divide it evenly. 360 is divisible by your friends 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20... it goes on.
fosiacat · 1 points · Posted at 16:16:43 on January 9, 2016 · (Permalink)
5 year olds dont know this.
SupersonicJaymz · 1 points · Posted at 16:25:54 on January 9, 2016 · (Permalink)*
Some army trades actually use mils, which divides the compass into 1000 points, counting up clockwise.
Edit: Sorry, turns out it's 6400 points. Too long since I used that stuff I guess.
My_usrname_of_choice · 1 points · Posted at 18:31:55 on January 9, 2016 · (Permalink)*
Mils= miliradians
I'm doing a service to point this out every time I see it in this thread. I only just learned this.
And it's 6400, not 1000
SupersonicJaymz · 1 points · Posted at 20:48:37 on January 9, 2016 · (Permalink)
Yeah, thats right. Sorry for the misinformation, it's been a long time since I took or used that training.
My_usrname_of_choice · 1 points · Posted at 21:45:47 on January 9, 2016 · (Permalink)
Mind blown on the other part though
RoboStalinIncarnate · 1 points · Posted at 16:50:08 on January 9, 2016 · (Permalink)
Good to know this. In grade school one time when I first learned about this 360 degree crap I actually caused a scene because I thought it was so fucking stupid.
[deleted] · 1 points · Posted at 17:14:56 on January 9, 2016 · (Permalink)
TIL 5 year olds could understand this.
How does this get so many upvotes lol it has nothing to do with this sub.
oversized_hoodie · 1 points · Posted at 17:18:15 on January 9, 2016 · (Permalink)
Radians with tau are better. /r/taumasterrace
Xaxxon · 1 points · Posted at 18:02:42 on January 9, 2016 · (Permalink)
"maths"? Is that something you can count? 2 maths? 3 maths?
skipweasel · 1 points · Posted at 19:13:44 on January 9, 2016 · (Permalink)
British English usage. Short for Mathematics.
Xaxxon · 1 points · Posted at 19:17:31 on January 9, 2016 · (Permalink)
wouldn't that be math's?
skipweasel · 1 points · Posted at 19:19:57 on January 9, 2016 · (Permalink)
Not really - we don't say bike's for bicycles, for example.
In the end, it's just usage.
http://grammarist.com/spelling/math-maths/
Exodus111 · 1 points · Posted at 18:04:33 on January 9, 2016 · (Permalink)
Just like to add that the 360 came from the ancient egyptians, who believed the sun completed one full rotation around the earth in 360 days (they were only off by 5 days or so, also by the sun not actually moving around the Earth).
And so they saw the number 360 as the number of the full rotation. In other words its totally arbitrary.
Radians are a mathically consistent manner of dividing a circle, but also useless in colloquial terms. A 90 degree angle, a 180 turn, a 360 flip, a 540 snowboard move.... These are terms radians have a hard time replacing.
enginrit · 1 points · Posted at 18:42:16 on January 9, 2016 · (Permalink)
Don't forget tau!
blaghart · 1 points · Posted at 18:45:41 on January 9, 2016 · (Permalink)
I've never seen an engineer use grads...we all use degrees or radians, depending on whether we're feeling like being patriotic or sensible.
robertdb · 1 points · Posted at 18:46:27 on January 9, 2016 · (Permalink)
I'm reading this "out loud" in my head: - 1 rad, - 2 rad, - 3 rad, - pirate! (Pi Rad)
underthehedgewego · 1 points · Posted at 18:57:44 on January 9, 2016 · (Permalink)
I purchased a compass at a flea market many years ago that was divided into 400 parts. I was told by some WW2 vets that it was a "gunnery compass". I don't know if that's true but it made sense to me, especially if you were training people without a math background; "0" is behind me, "100" is on my right, "200" is in front of me and "300" is to my left.
[deleted] · 1 points · Posted at 19:05:01 on January 9, 2016 · (Permalink)*
As a programmer this is often annoying because we're used to thinking most of the time in degrees but many libraries use radians. So it's always "here, I'll use degrees" and the result is a mess.
emdio · 1 points · Posted at 19:50:10 on January 9, 2016 · (Permalink)
Well, it's arbitrary in the sense that could exist -and of course exist- other ways to divide a circle, but calling it "arbitrary" is a bit unfair IMHO. For example;
http://mathforum.org/library/drmath/view/59075.html
UsediPhoneSalesman · 1 points · Posted at 20:01:07 on January 9, 2016 · (Permalink)
Radians aren't arbitrary like degrees or grads though.
always_down_voted · 1 points · Posted at 20:02:39 on January 9, 2016 · (Permalink)
The military uses mils = 1/6400 of the circumference.
not_that_shithead · 1 points · Posted at 20:21:29 on January 9, 2016 · (Permalink)
Theres also 6400 mils in a circle, but mils are used by the military as far as i know
iSmite · 1 points · Posted at 20:29:20 on January 9, 2016 · (Permalink)
I remember once my professor shad skmething about 360 degrees being arbitrary when compared to 2*pi.
Spnkmyr · 1 points · Posted at 20:56:37 on January 9, 2016 · (Permalink)
Also, 6400 mils in 360 degrees
Green-Brown-N-Tan · 1 points · Posted at 21:10:35 on January 9, 2016 · (Permalink)
In the military we use mils, which divide a circle by 6400. Its used for "accurate" mapping...
sinderling · 1 points · Posted at 23:06:41 on January 9, 2016 · (Permalink)
Sorry but 360 degrees is not arbitrary either.
[deleted] · 1 points · Posted at 01:35:01 on January 10, 2016 · (Permalink)
If it's of further interest, there has been debate about replacing 2Pi with Tau (which looks like a T), because a circle being 2 of something is notoriously confusing for students to learn. Think of how easy it is for anyone to imagine 90, 180, 270, 360 degrees. Yet even as a 2nd year undergrad who has used them for years, 3/2 Pi radians doesn't naturally or immediately mean anything to me, and when it does it's normally because I've converted it quickly to degrees in my head. So yeah. :)
The Babylonians used a base 60 numeral system because 60 was easily divided by most everyday numbers, and is why a minute has 60 seconds, an hour has 60 minutes, and a circle is most commonly referred to as 6 x 60 degrees.
qwerqmaster · 1 points · Posted at 01:40:45 on January 10, 2016 · (Permalink)
There's also hour, minute, and seconds, which is often used in astronomy to measure right ascension.
yurnotsoeviltwin · 1 points · Posted at 01:52:38 on January 10, 2016 · (Permalink)
Not quite. It's part of the fundamentals of Euclidian geometry. According to general relativity, spacetime operates according to non-Euclidian axioms.
cant_think_of_one_ · 1 points · Posted at 02:48:19 on January 10, 2016 · (Permalink)
Which is why degrees and grads are stupid.
In an unrelated point, my attempts to get people to use the Plank unit system outside of theoretical physics aren't progressing well.
skipweasel · 1 points · Posted at 09:31:34 on January 10, 2016 · (Permalink)
Smoots FTW.
cant_think_of_one_ · 1 points · Posted at 01:09:39 on January 11, 2016 · (Permalink)
You also need, at a minimum, a time and energy or mass unit to form a unit system. I wonder how long Oliver Smoot can hold his breath and how much he weighs.
RotWS · 1 points · Posted at 03:14:39 on January 10, 2016 · (Permalink)
And finally I know what the hell the grad button on my calculator does.
workworkworkwork123 · -6 points · Posted at 09:08:38 on January 9, 2016 · (Permalink)
Use Tau (τ) not 2Pi it makes the math much easer
Deadmist · 57 points · Posted at 09:24:41 on January 9, 2016 · (Permalink)
If not doubling a variable makes it much easier you should reconsider doing anything with math ;)
DeepReally · 21 points · Posted at 11:19:59 on January 9, 2016 · (Permalink)
There is a genuine movement to remove pi from mathematics and engineering. It's based on the cherry picking of certain formula to suggest that τ is a "more natural" constant. However, the movement has gain recognition among serious mathematicians due to the only benefit of writing one symbol rather than two is "a saving of ink."
If you look at the circumference of a circle, the unit circle has a radius of 2π or τ. τ may appear more "natural" in this case. However, when you consider the area of a circle, a unit circle has an area of π or τ/2 making π appear more "natural". There is no way to get rid of the factor of two from the nature of π, because it relates to both the circumference and the area of a circle. Any attempt to suggest otherwise is just cherry picking of formulae.
lurker628 · 1 points · Posted at 12:52:34 on January 9, 2016 · (Permalink)
A circle of radius a has area:
int(int(1 * r dr dtheta)), with bounds of r from 0 to a and theta from 0 to {2pi or tau}.
Call the upper bound of theta k.
intint(1 dA)
int(int(r, r, 0, a), theta, 0, k)
int(r2 / 2 | 0..a, theta, 0, k)
int(a2 /2, theta, 0, k)
1/2 * a2 * int(1, theta, 0, k)
1/2 * a2 * k
This isn't to say tau is better than pi, but the derivation "naturally" includes a factor of 1/2. One can choose the circle's proportionality constant to cancel with it, or one can leave it as is. The very idea of "better" - or even, as used here, "natural" - is subjective. It ties into the same question as what really counts as "simplifying."
It seems to me that, more than favoring pi or tau, we should be happy recognizing that the mathematics of circles doesn't change regardless of how one chooses to express the relationships. However, and for the record: Section 3 of the Tau Manifesto addresses precisely this issue, with Section 5 offering an extension for those with the chops.
TL;DR The beauty of math is that it doesn't really matter. That said, the example of a circle's area does not support your point.
[deleted] · 1 points · Posted at 13:31:57 on January 9, 2016 · (Permalink)
There is a genuine movement that is wrong.
There is nothing wrong with pi.
lurker628 · 1 points · Posted at 13:37:45 on January 9, 2016 · (Permalink)
There's nothing wrong with tau, either. Getting up in arms either way is what's ridiculous. It's just a fun discussion which helps emphasize that mathematics is valid without regard to one's choice of expression and that there are often interesting connections across seemingly disparate areas.
It is, however, possible to offer arguments which are themselves flawed, regardless of which form of the constant one intends to support.
[deleted] · 0 points · Posted at 13:40:07 on January 9, 2016 · (Permalink)
All I know is I've never heard anyone say "I'll have a delicious slice of half-Tau."
aris_ada · -2 points · Posted at 12:15:59 on January 9, 2016 · (Permalink)
It's not cherry picking. Take any formula that uses π and you'll find that it's more logically explained by using τ. For the disk's area for instance (apparently the only counterexample that exists), if you derive its formula, you naturally get the 1/2 the same way you get it in e = m*v2/2 in physics.
[deleted] · 10 points · Posted at 12:28:01 on January 9, 2016 · (Permalink)
interesting fact, if you replace the word "logically" with "elegantly" in the above argument it's STILL not a mathematical one.
[deleted] · 0 points · Posted at 13:26:47 on January 9, 2016 · (Permalink)
Some formulas for areas or volume work better (as in, fewer constants) with pi, e.g. the area of a circle.
FuckClinch · -2 points · Posted at 12:45:22 on January 9, 2016 · (Permalink)*
You don't "naturally get" the 1/2 at all. You're just putting Tau as your integration limit instead of 2π and saying it's natural that's completely ridiculous. Why is energy a gold standard for functions proportional to a squared power?
Additional counterexamples:
*Integral from -infinity to +infinity of e-x2 - you'd have some constant inside the root aswell as the π *Oh yeah, you also ruin eulers formulae with a nasty fraction of 1/2 or lose the minus sign - often called the most beautiful equation in mathematics
Seriously the decision is arbitrary and it's really not worth arguing, it would be an unbelievably ridiculous decision to change it.
Although for my 2 pence go team π purely because it ruins Eulers identity.
Edit: The reason I prefer eulers with -1 is because it's another layer of abstractness in the formulae, the concept of negative one things isn't amazingly intuitive in the same way as i and pi aren't. That's why I think it's neater.
aris_ada · 1 points · Posted at 13:12:13 on January 9, 2016 · (Permalink)
The pi police is there...
ei tau=1. Look how we ruined it.
[deleted] · 1 points · Posted at 13:28:51 on January 9, 2016 · (Permalink)
You don't ruin Euler's formula using tau. You actually make it better.
eiπ = -1
eiτ = 1
lurker628 · 0 points · Posted at 13:10:31 on January 9, 2016 · (Permalink)
I did it with k here. You do get a factor of 1/2, thanks to the integration of r with respect to r. Whether it's "natural" to keep that factor independent or to want to simplify is subjective, but the factor does appear without regard to the use of pi or tau as a bound.
The whole beauty of math is that it doesn't really matter. It's all valid regardless of how one chooses to express the constants. The example of a circle's area, however, doesn't support the claim.
FuckClinch · 1 points · Posted at 14:27:56 on January 9, 2016 · (Permalink)
Whilst I agree by the same logic you could argue a 1/3 is "natural" for a sphere because of the dependence on a2 being integrated. I'm going to stop with this now because it's, as you said it doesn't really matter and it wasn't even you I was arguing with!!
Thanks for spending the time to chat!
[deleted] · 0 points · Posted at 12:26:07 on January 9, 2016 · (Permalink)
it's pretty easy to use tau in your math paper, just write at the top
tau=2pi
TheRealDudeGuy · -3 points · Posted at 12:02:51 on January 9, 2016 · (Permalink)
Even so, I'd prefer τ. Mostly because I get annoyed with the whole pi = pie thing; unfortunately Tau-day could still be a thing.
Nemisii · 7 points · Posted at 12:26:54 on January 9, 2016 · (Permalink)
As an engineer: Fuck Tau. We already use T and t for a a bunch of different things, using tau instead of pi just makes things harder to parse.
Kayyam · 1 points · Posted at 13:03:45 on January 9, 2016 · (Permalink)
Word. Pi is like at the heart of mathematics, how the fuck do you want to change it now after centuries of it being ingrained at the core of science ?
lurker628 · 2 points · Posted at 13:22:44 on January 9, 2016 · (Permalink)
No. The "heart" of mathematics is that it doesn't make any difference whether you choose to express relationships with pi or with tau.
Social inertia is not a valid mathematical reason for not altering something.
Subjective determination of elegance is not a valid mathematical for altering something.
The meaningful purposes of the discussion are (a) to further understanding of connections among apparently different approaches or results and (b) to better solidify understanding that mathematics' validity does not depend on the symbols used.
Beyond that, it's just for fun.
AyeBraine · 2 points · Posted at 12:38:06 on January 9, 2016 · (Permalink)
Don't despair. Russians say it like "pee".
entotheenth · 12 points · Posted at 10:05:44 on January 9, 2016 · (Permalink)
2's are hard.
MPixels · 2 points · Posted at 10:11:59 on January 9, 2016 · (Permalink)
Do enough maths and you'll realise 2Pi crops up much more often than Pi, meaning Tau is the fundamental constant, not Pi
ManLeader · 21 points · Posted at 11:39:57 on January 9, 2016 · (Permalink)
You'll also realize that 4pi crops up a bunch. Oh no! Now it's 2tau.
Seriously, changing which one is the 'mainstream' constant is more trouble than it is worth, mostly because it isn't worth much.
MPixels · 2 points · Posted at 12:10:53 on January 9, 2016 · (Permalink)
I wasn't proposing we overhaul mathematics to replace Pi. Just pointing out it'd be simpler if Babylonian mathematicians had arrived at Tau in the first place.
Kayyam · 3 points · Posted at 13:04:59 on January 9, 2016 · (Permalink)
Babylonians didn't arrive at Pi and radians. They are the one responsible for the 360 degrees clusterfuck though.
MPixels · 1 points · Posted at 13:30:23 on January 9, 2016 · (Permalink)
They were calculating using an approximation of Pi first.
[deleted] · 2 points · Posted at 13:33:05 on January 9, 2016 · (Permalink)
I thought Pi was from the Greeks?
I mean, isn't it literally one of their letters?
I believe it is pronounced "Delicious".
aris_ada · -1 points · Posted at 12:17:57 on January 9, 2016 · (Permalink)
The amount of 2tau or tau/2 you find in important formulas (math + physics) is anecdotal when compared to tau or 2pi.
[deleted] · 2 points · Posted at 11:18:41 on January 9, 2016 · (Permalink)
what's the surface of an ellips?
MPixels · 3 points · Posted at 12:08:47 on January 9, 2016 · (Permalink)
A complicated infinite series with upper bound 2Pi*a
Artefact2 · 2 points · Posted at 12:33:51 on January 9, 2016 · (Permalink)
…No, it's πab.
He said surface, not perimeter.
MPixels · 2 points · Posted at 13:28:10 on January 9, 2016 · (Permalink)
Surely that's area. 2D shapes don't have a surface per se. That's for 3D shapes.
Sorry, I'd never heard surface in reference to a 2D shape before so I guessed
CaptHunter · 1 points · Posted at 13:44:30 on January 9, 2016 · (Permalink)*
Just because one appears more than another does not mean it's the fundamental. Not by any stretch. In fact, they define each other on an equal unit basis, meaning they are equally as "fundamental" as each other.
I'll explain - the units of Energy are J = kg·m2·s-2 . I can define the kilogram, therefore, as kg = m2·J·s-2 ... but this does not make the Joule (J) a base unit.
In my current line of study, Joules come up much more than Kilograms. Base unit? Nope.
MPixels · 1 points · Posted at 13:55:09 on January 9, 2016 · (Permalink)
What I'm saying is that it's the difference between having grammes or kilogrammes as a base unit. The latter was chosen because it was simpler that way and you didn't have to multiply by a thousand all the time.
CaptHunter · 1 points · Posted at 14:17:42 on January 9, 2016 · (Permalink)
Yes, but there aren't 6 other equivalents to work with when we're talking about radians. In fact, the kilogram is more an issue of naming convention - it already existed pre-SI.
MPixels · 0 points · Posted at 14:25:35 on January 9, 2016 · (Permalink)
sigh I know... we're not really communicating properly here so nvm
[deleted] · 0 points · Posted at 12:29:11 on January 9, 2016 · (Permalink)
not sure what you've got yourself there is an argument. what does funamental mean?
MPixels · 0 points · Posted at 13:29:39 on January 9, 2016 · (Permalink)
Fundamental: "Forming the necessary base or core"
[deleted] · 1 points · Posted at 13:43:37 on January 9, 2016 · (Permalink)
sooo, if tau is fundamental and 2 is fundamental, then pi is fundamental because tau=2 pi and pi=tau/2
MPixels · 1 points · Posted at 13:52:56 on January 9, 2016 · (Permalink)
That's not how it works...
[deleted] · 1 points · Posted at 14:55:20 on January 9, 2016 · (Permalink)
well you were the one who defined fundamental as being "the core" or something. I took that to mean generators of some set under the standard arithmetic operations. pi and tau generate the same set, so they are equally fundamental.
[deleted] · 1 points · Posted at 14:57:12 on January 9, 2016 · (Permalink)
[removed]
[deleted] · 1 points · Posted at 16:47:55 on January 9, 2016 · (Permalink)
[removed]
[deleted] · 2 points · Posted at 16:57:42 on January 9, 2016 · (Permalink)
Let's just call this the end of this discussion.
LittleDinghy · 2 points · Posted at 12:47:41 on January 9, 2016 · (Permalink)
However, if you consider the visual part of things, sticking with π is much better than replacing it with τ. T and t are very widely used for other things, and both of them are visually similar to τ. However, π has no other closely similar common symbol, unless you count n. And I have never seen anyone confuse a π with an n.
erdschein10 · 0 points · Posted at 12:47:28 on January 9, 2016 · (Permalink)
No, it really does not.
FeastofFiction · 0 points · Posted at 14:18:44 on January 9, 2016 · (Permalink)
I'm surprised you didn't mention computer programmers. Most standard math libraries have abandoned degrees at this point. Radians are far simpler to work with. The only reason people find them confusing is because they are taught degrees first and have that cemented in their minds before being exposed to radians. I teach some young children (grad 5-9) math, programming and some trig. The younger ones have absolutely no issue with radians. It's much more intuitive that turning around would be 1pi than 180 to them.
user_82650 · 0 points · Posted at 14:40:20 on January 9, 2016 · (Permalink)
Which is why tau is better.
permalink_save · 0 points · Posted at 16:40:27 on January 9, 2016 · (Permalink)
AKA Tau.
AllanKempe · 118 points · Posted at 15:40:57 on January 9, 2016 · (Permalink)*
Yes, it's arbitrary. But very convenient since 360 = 2 x 2 x 2 x 3 x 3 x 5 (prime factorization) so that it's divisible by 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360 (yes, that's 24 divisors!). That is, if you divide a circular disc into 1, 2, 3, 4, ..., 90, 120, 180, 360 equally large sectors all of them will have an integer angle measured in degrees: 360, 180, 120, 90, ..., 4, 3, 2, 1 degree(s), respectively.
Triquetra4715 · 54 points · Posted at 19:41:58 on January 9, 2016 · (Permalink)
24 divisors, one of which is 24, which is exciting.
AllanKempe · 14 points · Posted at 19:57:11 on January 9, 2016 · (Permalink)
Ssssh, we don't want the numerologists in here to know this!
GIS-Rockstar · 1 points · Posted at 02:07:44 on January 10, 2016 · (Permalink)
Too late. GOt teh tattoo.
Best_Underacheiver · 1 points · Posted at 03:30:24 on January 10, 2016 · (Permalink)
yeah because they will babylon and on about it
AdvicePerson · 1 points · Posted at 02:05:35 on January 10, 2016 · (Permalink)
You sound like fun.
stonefit · 1 points · Posted at 01:10:36 on January 10, 2016 · (Permalink)
WHERE THE FUCK IS JACK BAUER!
CaptainUnusual · 14 points · Posted at 20:43:24 on January 9, 2016 · (Permalink)
For comparison, if we divided a circle into 100 degrees, which is 2 x 2 x 5 x 5, it would only be divisible by 1, 2, 4, 5, 10, 20, 25, 50, 100 (which is only 8 divisors) giving us significantly fewer options.
AllanKempe · 6 points · Posted at 20:46:16 on January 9, 2016 · (Permalink)
Indeed. That's why I'm against base 10. We should use base 12, has significantly more divisors though not being a much bigger number.
hexane360 · 7 points · Posted at 23:48:42 on January 9, 2016 · (Permalink)
Yep. This helps with time too. 10 (in base 12) hours, and 50 (in base 12) minutes
W_T_Jones · 3 points · Posted at 00:57:52 on January 10, 2016 · (Permalink)
I don't think having more divisors offsets having to get used to using base 12.
xxfay6 · 1 points · Posted at 08:54:05 on January 10, 2016 · (Permalink)
Anything wrong with Hexadecimal?
urgrandpasdog · 1 points · Posted at 11:16:19 on January 10, 2016 · (Permalink)
Well you lose the ability to divide things by 3 nicely.
[deleted] · 1 points · Posted at 05:35:12 on January 10, 2016 · (Permalink)*
[deleted]
AllanKempe · 1 points · Posted at 15:05:21 on January 10, 2016 · (Permalink)
Perhaps, but it wasn't the compass that was the first application of the concept of angles, it was geography, astronomy and architecture.
geppetto123 · 1 points · Posted at 15:47:20 on January 10, 2016 · (Permalink)
In comparison the much larger number 1000 has only 12 integer divisiors - so I would say the Mayas didn't choose it arbitrarily.
AllanKempe · 1 points · Posted at 15:52:39 on January 10, 2016 · (Permalink)*
It's arbitrary in the sense that the only reason 360 was used is that is has so many divisors (and isn't too large). And wasn't it the Egyptians (based on the Mesopotamians' base 60 system) that invented the 360-degree circle? (I mean, used by us today.)
Gumnutbaby · 1 points · Posted at 21:36:11 on January 10, 2016 · (Permalink)
The convenience was close to what I had guessed. 360 is divisible by a much greater range of numbers than 100!
AllanKempe · 1 points · Posted at 18:24:04 on January 11, 2016 · (Permalink)
Indeed, but one must also take into account that 360 is a larger number than 100.
[deleted] · 60 points · Posted at 12:56:08 on January 9, 2016 · (Permalink)*
Mils is another division. 6400 mils to a circle which is what the us army uses in some circumstances and has a beautiful relationship when relating to meters at distance so that 1 mil at a distance of 1km has a length of 1 meter and 2 meters at 2 km and so on.
Edit: 6400 mils. 1600 to a 90deg angle
[deleted] · 27 points · Posted at 13:14:16 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 6 points · Posted at 13:44:35 on January 9, 2016 · (Permalink)
I forget what the soviets used for their mils, and I'm too lazy to google, think it was 6440 or something. Had to briefly learn it when teaching the d-30. Until I was taught it I had no idea what the reticle pattern in binos was for and can't believe pre22 he old me never thought to ask.
[deleted] · 4 points · Posted at 14:16:29 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 5 points · Posted at 15:23:14 on January 9, 2016 · (Permalink)
Soviet Union used 6000, which makes sense, as their artillery was inherently less accurate and designed for barrages rather than precision. Lot of FIFI
[deleted] · 2 points · Posted at 18:10:15 on January 9, 2016 · (Permalink)
Unrelated, but I got to be part of a battery laid using the stars, supposedly through a method taken from some old Soviet manual. It was kinda neat.
[deleted] · 1 points · Posted at 14:48:45 on January 9, 2016 · (Permalink)
The AFATDS computes with the exact mil relation? I thought we used 6400 IOT bump with charts?
[deleted] · 1 points · Posted at 16:10:29 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 2 points · Posted at 18:08:06 on January 9, 2016 · (Permalink)
That doesn't make sense, though. No one on the gun line cares about the actual value of a mil. To us, it's just a measurement - a little more convenient than degrees due to the size of the unit, but that's it. And with all of the redundancies and safety measures, why risk problems caused by defining a word two different ways?
I mean, why tell the gun bunnies 6400?
dantheman_woot · 1 points · Posted at 13:54:01 on January 9, 2016 · (Permalink)
Yep used mils as a forward observer in the Army. There are 17.777... mils to one degree.
solstice035 · 1 points · Posted at 17:08:15 on January 9, 2016 · (Permalink)
Also used for basic navigation in the British Army (source: ex infantry officer)
[deleted] · 10 points · Posted at 15:14:48 on January 9, 2016 · (Permalink)*
[deleted]
[deleted] · 3 points · Posted at 15:24:30 on January 9, 2016 · (Permalink)
Which makes complete sense as the exact mil breakdown is 2pi
aniseikonia · 2 points · Posted at 22:01:20 on January 9, 2016 · (Permalink)
And since sin(x) is roughly x, for x small enough... When using radians.
My_usrname_of_choice · 3 points · Posted at 18:32:37 on January 9, 2016 · (Permalink)
Mils= miliradians
I'm doing a service to point this out every time I see it in this thread. I only just learned this.
maladat · 2 points · Posted at 23:52:20 on January 9, 2016 · (Permalink)*
6400 mils in a circle is an approximation used to make certain types of ranging math easier to do in your head.
There really are 6283.185307.... mils in a circle, because "mils" is short for "milliradians," or thousandths of radians.
There are 2PI radians in a circle. There are 2000PI mils in a circle.
Also, the relationship you mention doesn't really have anything to do with meters at all. Being a thousandth of a radian, a mil subtends an arc 1/1000th the radius of the arc.
You gave the relationship of 1m at 1km (1000m), but it works for any units.
1 cm at 1000 cm. 1 foot at 1000 feet. 1 parsec at 1000 parsecs. All one mil. Units don't matter.
noodlehoodlum · 1 points · Posted at 17:26:42 on January 9, 2016 · (Permalink)
you're an artillery man aren't you?
[deleted] · 1 points · Posted at 17:48:12 on January 9, 2016 · (Permalink)
Do sniper sights use mils?
darkenseyreth · 1 points · Posted at 18:58:21 on January 9, 2016 · (Permalink)
I loved Mils. The whole MGRS system is fantastic and I wish it would get more widespread civvy use.
Cockatoo010 · 1 points · Posted at 20:20:29 on January 9, 2016 · (Permalink)
Aren't mils that line marks on long range weapons scopes?
qwopax · 1 points · Posted at 20:34:36 on January 9, 2016 · (Permalink)
Hah! The imperial mils is much easier, that's 1 foot at 1 mile. There's 33595 imperial mils to a circle, which is more natural than your arbitrary value.
More seriously, I would expect 2000∏ = 6283 mils to a circle. Your meter is actually 98cm, close enough that ease of use trumps precision.
NotActuallyAWookiee · 1 points · Posted at 21:33:01 on January 9, 2016 · (Permalink)
Mils ftw. I'm sure there are a bunch of specialised reasons for the number. To me it just means you don't have to talk in fractions. Regular rads and you're expressing fractions of degrees as soon as you step beyond NE / SE.
JeffIrwin · 1 points · Posted at 23:18:16 on January 9, 2016 · (Permalink)
The term "mils" can also refer to 1/1000 of an inch (i.e. milli-inch). This is common among machinists.
splendidfd · 441 points · Posted at 07:57:34 on January 9, 2016 · (Permalink)
It is arbitrary, but 360 is a number with a lot of factors so it is easy to divide.
For something less arbitrary radians are often used in mathematics/scientific applications, the whole circle is 2pi radians, which meshes well with the trigonometric functions (cos, sin, etc).
mrmaul558 · 113 points · Posted at 13:19:34 on January 9, 2016 · (Permalink)
Radians are actually derived from the arc length formula. 1 radian is exactly the angle required for the arc length to equal the radius.
acog · 41 points · Posted at 15:10:48 on January 9, 2016 · (Permalink)
In case anyone missed it, this handy visualization was posted in the top comment chain.
titaniumjew · 2 points · Posted at 20:55:31 on January 9, 2016 · (Permalink)
Which is why we use 12 in imperial.
superalienhyphy · 2 points · Posted at 01:47:43 on January 10, 2016 · (Permalink)
This should be the top comment
jatheist · 3 points · Posted at 16:10:48 on January 9, 2016 · (Permalink)
Or tau radians.
Strojac · 1 points · Posted at 14:12:29 on January 9, 2016 · (Permalink)
To go from Degrees to Radians, multiply by π/180. The other way, multiply by 180/π
TheKitsch · 1 points · Posted at 20:31:44 on January 9, 2016 · (Permalink)
even our current base 10 number system is arbitrary.
I personally think we should pick a new one though. base 16 would be perfect because hex, 32 even better, and 64 even more so.
16 though because 32 and 64 would just be too annoying to learn.
[deleted] · -4 points · Posted at 14:08:35 on January 9, 2016 · (Permalink)
[deleted]
methyboy · 9 points · Posted at 16:07:15 on January 9, 2016 · (Permalink)
There's a slight difference between the mathematical usage of "arbitrary" and the everyday usage of that word. Mathematically, "arbitrary" typically means something like "can be changed without any real consequence: it's a human construct, not a fundamental mathematical fact".
Examples of mathematically arbitrary things are the fact that we use base 10, the fact that there are 360 degrees in a circle, and the the order of operations (BEDMAS/PEDMAS/whatever you call it). Examples of things that are not mathematically arbitrary are things like the Pythagorean theorem (in a right triangle, the sum of the squares of the two short sides equals the square of the length of the third side), the fact that pi is transcendental, and the fact that you can't square a circle.
Visell · -4 points · Posted at 17:36:06 on January 9, 2016 · (Permalink)
Tell that to fat nerds
[deleted] · -1 points · Posted at 15:43:11 on January 9, 2016 · (Permalink)
Degrees comes from old sailing navigation a degree is how much the stars would shift in a day or something like that. 360~365
GueroCabron · 166 points · Posted at 13:32:07 on January 9, 2016 · (Permalink)
On one hand, count the lines of your fingers with your thumb. 3 on each finger, 4 fingers
3x4=12
Each time you count all the lines, put up one finger on your other hand. 5 fingers, 12 lines, 5x12=60.
This is the 60 base counting system, and it was used by the babylonians/sumerian civilizations, and was adopted by a lot of math 'cults' from a long time ago.
60 minutes/hr
60 seconds/minute
ELI5: Ancient math wasnt based on 100, we did that because modern civilzations connect to it better because we count like barbarians using one finger per count and top out at 10. If you counted using a 12/60/144 based systems, we would be asking why metric is 10 based.
Best_Towel_EU · 19 points · Posted at 15:06:41 on January 9, 2016 · (Permalink)
I never considered that method of counting, gonna use that now.
beeeel · 40 points · Posted at 16:00:06 on January 9, 2016 · (Permalink)
Try binary counting. By using each finger as a binary bit (0 when down, 1 when up), you can count to 1023 (210-1) using both hands. One hand will get you to 31.
[deleted] · 7 points · Posted at 19:18:39 on January 9, 2016 · (Permalink)
And now I am trying to binary count using knuckles. This will not end well.
wrecklord0 · 2 points · Posted at 08:56:42 on January 10, 2016 · (Permalink)
Pretty hard to move all knuckles arbitrarily because of how they are articulated... but its fairly easy to have at least 4 positions (2 bits) per finger. Therefore 20 bits across both hands.
220 = 1,048,576. Such power!
probablyNOTtomclancy · 3 points · Posted at 20:15:42 on January 9, 2016 · (Permalink)
I don't get it...
beeeel · 9 points · Posted at 20:25:20 on January 9, 2016 · (Permalink)
Put out your left hand, palm down, all fingers curled up. You thumb is worth 1, your index finger is worth 2, your middle finger is worth 4, your ring finger is worth 8, and your little finger is worth 16.
To represent 1, you just put your thumb up. For 2, you put your index finger up and thumb down. For 3 it's index and thumb. For 4, it's just middle finger.
By adding the fingers together it's possible to make all the numbers from 0 to 31 with a single hand. If you use both hands, then the first finger on the second hand is worth 32 (twice 16), and the second is worth twice that, until the last finger is worth 512.
This is exactly the same way that written binary numbers work- the furthest right digit represents 1, and then the next one on the left is 2, then 4, etc. It's not dissimilar to how decimal (normal numbers) work- the digit to the left of the decimal point is how many times 100 (1) you have, the next number is how many times 101 (10) you have, then 102 (100) and so on.
IBuildBrokenThings · 3 points · Posted at 17:45:19 on January 9, 2016 · (Permalink)
8 to about 13 are incredibly awkward to hold though, can definitely see why it wouldn't have caught on.
Xilar · 14 points · Posted at 18:30:24 on January 9, 2016 · (Permalink)
And 4 isn't really nicest.
gumnos · 8 points · Posted at 18:31:26 on January 9, 2016 · (Permalink)
4, 128, and 132 are socially awkward too.
Hey, man, no offense. Just counting here.
beeeel · 1 points · Posted at 18:47:57 on January 9, 2016 · (Permalink)
Turn your hand over. That makes 8 and 13 much easier.
PallBear · 1 points · Posted at 19:29:04 on January 9, 2016 · (Permalink)
I used to do this to pass time while working my student job at the university library desk. Then I discovered there were BOOKS there
beeeel · 1 points · Posted at 20:10:36 on January 9, 2016 · (Permalink)
That's like going on Reddit and spending time on /r/counting- there's all the fish memes you could look at, but instead you're counting.
Triquetra4715 · 1 points · Posted at 19:39:49 on January 9, 2016 · (Permalink)
Ableist as shit.
TLDM · 1 points · Posted at 20:34:50 on January 9, 2016 · (Permalink)
You can kind of do this in base 3 as well, if you can think of a decent way to represent adding and subtracting a digit (e.g. adding could be finger up, subtracting could be finger half up? That's quite difficult to do though...). You can go from -29594 up to 29594 on two hands with this method - but it's slightly useless. Still, an interesting concept.
beeeel · 1 points · Posted at 20:48:29 on January 9, 2016 · (Permalink)
It's unlikely that you want to subtract, anyway, since you're normally either counting up or down- do you could make it to 59048 with both hands, or 19682 with one.
But realistically, you're not going to do addition/counting beyound a few hundred on your hands, are you?
TLDM · 1 points · Posted at 21:08:57 on January 9, 2016 · (Permalink)
Not with base three - either you need one way to show adding and one for subtracting, or one way to represent a 1 and another to represent a 2.
But yes, this is a bit ridiculous.
Lanaru · 0 points · Posted at 18:33:02 on January 9, 2016 · (Permalink)
Too much thinking involved.
bobocalender · 3 points · Posted at 18:16:04 on January 9, 2016 · (Permalink)
Glad to see someone mention the Babylonians here. While the use of dividing up a circle into 360 degrees is arbitrary today, there was a reason for its origins.
ziusudrazoon · 1 points · Posted at 18:16:48 on January 9, 2016 · (Permalink)
I prefer to think of it as counting the bones of the fingers.
En_lighten · 1 points · Posted at 18:37:26 on January 9, 2016 · (Permalink)
That may not be entirely true, but has truth in it. Interesting, anyway. https://en.m.wikipedia.org/wiki/Sexagesimal
OFF_THE_DEEP_END · 1 points · Posted at 18:55:32 on January 9, 2016 · (Permalink)
This. And to expand on how a circle was conceptualized in terms of sixty, a circle can be divided into six equilateral triangles. Each triangle has 180 degrees, with the center of the circle at the center of the points of six triangles.
The angles of the six triangles that are at the center are six times sixty.
JeffIrwin · 1 points · Posted at 00:10:48 on January 10, 2016 · (Permalink)
FTFY
sgtwoegerfenning · 1 points · Posted at 12:04:08 on January 10, 2016 · (Permalink)
Nope 180. Think of the special triangles. 90 + 60 + 30, 90 + 45 + 45, 90 + 90 + 0. All come out at 180.
JeffIrwin · 1 points · Posted at 19:07:12 on January 10, 2016 · (Permalink)
My bad, I thought you were just referring to the angle at the center, not the sum of all three.
sgtwoegerfenning · 1 points · Posted at 19:45:16 on January 10, 2016 · (Permalink)
Might have done. I reread his comment and now I'm unsure
jbtum · 1 points · Posted at 20:05:33 on January 9, 2016 · (Permalink)
Is that why we have a special name for 12, namely twelve and not ten-and-two?
GueroCabron · 1 points · Posted at 20:09:42 on January 9, 2016 · (Permalink)
Never thought of that, but I would assume so!
curious-soul · 1 points · Posted at 23:21:58 on January 9, 2016 · (Permalink)
It was your comment that finally made me think of this. ....
https://youtu.be/_uJsoZheTR4
GueroCabron · 1 points · Posted at 23:25:24 on January 9, 2016 · (Permalink)
Id love to have been comfortable with a 60base system
pfafulous · 1 points · Posted at 06:49:21 on January 10, 2016 · (Permalink)
Oh how I wish we were a base-12 civilization. Everything would be so much easier.
Measure76 · -1 points · Posted at 16:31:10 on January 9, 2016 · (Permalink)
Barbarians? I was sure we used base 10 to allow decimal math. Would decimals even be possible in base 60?
[deleted] · 9 points · Posted at 17:30:15 on January 9, 2016 · (Permalink)
Numbers after the decimal point simply represent fractional numbers. For instance, 0.124 means 1 of 1/10 plus 2 of 1/100 plus 4 of 1/1000. We could just as easily do this in any base.
In base 60, we would just have to use powers of 60 for the fractions. In fact, we could write some numbers as exact decimal points in base 60 that we can't write in base 10. For instance, 1/30 is 2/60 = .2 in base 60 expansion, while it equals .03333... in base 10 notation.
Technically, we wouldn't call them "decimals" though, since decimal literally just means ten or one tenth.
mdruskin · 3 points · Posted at 16:54:50 on January 9, 2016 · (Permalink)
yes https://en.wikipedia.org/wiki/Radix_point
[deleted] · 0 points · Posted at 19:05:51 on January 9, 2016 · (Permalink)
Of course. Do you think math would be impossible if we had evolved with 12 fingers? Or 16? 10 is completely and utterly arbitrary, mathematically speaking.
Measure76 · -2 points · Posted at 19:08:49 on January 9, 2016 · (Permalink)
Yeah, they're possible, but easy written math, accounting and such, is so much easier in base 10.
JeffIrwin · 1 points · Posted at 23:28:13 on January 9, 2016 · (Permalink)
No, base 10 isn't easier. It seems easy just because you're used to it.
In fact, base 12 arithmetic is easier than base 10. In base 10, it's easy to remember the multiples of 5 because they all end in 0 or 5 (e.g. 10, 15, 20, 25, ...). That's because 5 is a factor of 10. Now 12's factors are 2, 3, 4, and 6, whereas 10's are only 2 and 5. That means base 12 has a whole lot more numbers that are easy to multiply and divide than base 10.
Of course, there's a tradeoff. 24 has even more factors than 12, but memorizing a 24 x 24 sized multiplication table probably isn't worth it.
horneke · 1 points · Posted at 00:28:23 on January 10, 2016 · (Permalink)
Base ten. When you switch base numbers, your digits change. In base twelve, 12 becomes 10, 144 becomes 100, etc. You just need more, or less, digits depending on what base you are using. Binary is another example where 10 doesn't equal ten.
[deleted] · 1 points · Posted at 03:04:08 on January 10, 2016 · (Permalink)
No, for serious... It's only because we're used to it. And we're used to seeing the digits 0-9. But if you here up with 12 squiggly digits, or 8, or 16, you would think it just as easy, and math would work the same. Multiplication, fractions, it would all basically be the same.
Or do you think we just coincidentally hit on the exact right number of fingers to have to make universal math easier?
Measure76 · 0 points · Posted at 07:54:57 on January 10, 2016 · (Permalink)
No, I think that we used many different bases as needed, but that for modern accounting to take off, base 10 was settled on. (I mean, our verbal language even has unique numbers to 12 before going into a pattern, so it isn't about fingers at all, in any way)
[deleted] · 1 points · Posted at 15:25:31 on January 10, 2016 · (Permalink)*
I'm really having difficulty understanding how you're not understanding this, with several different people telling you that's simply not the way things are.
You're simply making up whatever comes into your head, but that isn't the way history works. What evidence do you have for this assertion, or does it simply "feel right" to you, based on a few comments you've read in this thread?
Great, you heard that the Babylonians had a base-sixty system. Are you aware that they actually counted their values below sixty in bundles of ten? And that all our records of counting for thousands of years before them were in base-ten? That there is no ancient Indoeuropean counting system that doesn't involve sets of ten?
Unique names until 12 has nothing to do with what you think it does. No Indoeuropean system was base-twelve, even in words. The words for eleven and twelve come from Proto-Germanic *ainlif and *twalif (respectively one left and two left), both of which were words using a decimal notation.
And you still seem to be failing to understand the basic point: do you really think it's a coincidence that we evolved ten fingers -- which even you must understand had nothing to do with counting -- and the fact that all ancient counting systems involve bundles of ten?
Nor have you given any evidence of your assertion that base-ten is easier for modern accounting than base-eight or base-twelve would be, had we evolved with eight or twelve fingers.
leadchipmunk · 221 points · Posted at 07:55:52 on January 9, 2016 · (Permalink)
Yup. Completely arbitrary. The Sumerians and Babylonians used a sexagesimal counting system, or base 60 (as opposed to our decimal, base 10, system). They said a circle could be divided into 6 60-counts, or 360 degrees, and we have stuck with that since.
That's also why we have 60 minutes in an hour and 60 seconds in a minute.
ballaman200 · 60 points · Posted at 10:42:32 on January 9, 2016 · (Permalink)
Cool thing to know: Thats also the case why much languages have specific names for 11 and 12 (eleven,twelve,onze,douze,elf,zwölf) if you want to know more just google: "duodecimalsysten".
Edit: spelling
anotherseemann · 32 points · Posted at 15:52:49 on January 9, 2016 · (Permalink)
Found the german!
andreasbeer1981 · 10 points · Posted at 16:51:58 on January 9, 2016 · (Permalink)
Germans would've put an m at the end ;)
stephanplus · 11 points · Posted at 18:04:12 on January 9, 2016 · (Permalink)
In German it would be "Duodezimalsystem"
exploding_cat_wizard · 2 points · Posted at 18:15:29 on January 9, 2016 · (Permalink)
Though ballaman sounds very German, and would easily include wrong grammer ;)
ballaman200 · 3 points · Posted at 21:01:54 on January 9, 2016 · (Permalink)
damn, you got me :(
Ya_B0y_Bill_Nye · 3 points · Posted at 21:43:48 on January 9, 2016 · (Permalink)
so true. Learning German isn't always bad, cause half the time the "new" words are just old words pushed together.
m1serablist · 21 points · Posted at 12:39:09 on January 9, 2016 · (Permalink)
sexagesimal, probably the dirtiest sounding math thing I've ever heard.
Nmaka · 3 points · Posted at 17:09:05 on January 9, 2016 · (Permalink)
Sexy primes?
-Reddit_Account- · 2 points · Posted at 22:42:34 on January 9, 2016 · (Permalink)
What about circumscribing shapes?
JeffIrwin · 2 points · Posted at 00:22:52 on January 10, 2016 · (Permalink)
Bijection and surjection?
[deleted] · 6 points · Posted at 12:59:27 on January 9, 2016 · (Permalink)
And also why 13 is an unlucky number , as it breaks the beauty of 2*6
NotoriousCOP · 3 points · Posted at 12:50:51 on January 9, 2016 · (Permalink)
I've heard the reason 360 was chosen is because in history it was thought it took 360 days to circulate the sun. Wound up being 5.25 days off.
[deleted] · 31 points · Posted at 09:36:41 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 67 points · Posted at 12:44:22 on January 9, 2016 · (Permalink)
Arbitrary and random are two completely different things, and while something surely can be arbitrary if it's random or whimsical – the opposite often isn't true.
In essence, "arbitrary" can be thought of as "for any or no reason".
Example: When asked my favourite number, I answer 17 because I think it's the best number. I've always liked 17 the most, so it's not whimsical. I'll also always answer 17, so it's not random. It is, however, arbitrary.
jjxanadu · 7 points · Posted at 14:41:00 on January 9, 2016 · (Permalink)
Damn it... now I have to get a new favorite number... I hope no one has 18...
SuperC142 · 19 points · Posted at 15:17:54 on January 9, 2016 · (Permalink)
Lots of people have 17; it's a prime choice.
bigfish42 · 3 points · Posted at 17:46:38 on January 9, 2016 · (Permalink)
Dammit dad. Go home.
hirjd · 1 points · Posted at 18:17:00 on January 9, 2016 · (Permalink)
I choose 30. The average of 29 and 31, both prime. Also the average of 23 and 37, next pair both prime. And it's like that for 5 pairs of primes. A small number for such a claim.
gabisver · 1 points · Posted at 20:25:53 on January 9, 2016 · (Permalink)
18 is mine, keep moving
KuntaStillSingle · 2 points · Posted at 16:57:01 on January 9, 2016 · (Permalink)
No, arbitrary isn't for any reason. If so you could say any decision at all is completely arbitrary, as they exist for some reason or it is made for no reason.
Something which is arbitrary is something which is decided randomly, at a personal whim, or otherwise such that though it may make sense for the person who decides it appears random or whimsical to others. The comment you are replying to more closely captured the definition then your own, though your example hits it right on the head. You had a reason for choosing 17 as your favorite number and maybe even one for considering it the best number, but to anyone else it seems like a random or whimsical choice.
LunchbreakLurker · 3 points · Posted at 16:18:13 on January 9, 2016 · (Permalink)
Logged in just to upvote your comment
ProjectDirectory · 3 points · Posted at 16:44:14 on January 9, 2016 · (Permalink)
Very important when dividing a pizza with friends.
[deleted] · 2 points · Posted at 14:41:10 on January 9, 2016 · (Permalink)
According to who? Your own personal dictionary that nobody else uses? In this day and age I'm baffled that someone can dare make such blatantly wrong statements without even checking in an online dictionary or something like that... Here's what "arbitrary" means according to Merriam-Webster:
I highlighted the definition that I think is the most relevant here. There's nothing intrinsic about 360°, but we chose it because it's convenient. It very well fits the definition of "arbitrary".
Mrknowitall666 · -1 points · Posted at 16:19:06 on January 9, 2016 · (Permalink)
360 still isn't arbitrary. It's based on counting all the digits of your fingers from ancient Mesopotamia
[deleted] · -2 points · Posted at 16:23:13 on January 9, 2016 · (Permalink)
It's like you didn't even read what I wrote. Here, I'll paste the definition again:
Is 360° based on necessity (will the world end if we choose 12345° instead?) or on the intrinsic nature of the circle? No. Was it based on the convenience of being able to count on your fingers and divide it into many pieces? Yes. I can't make this any clearer...
Mrknowitall666 · 1 points · Posted at 18:38:51 on January 9, 2016 · (Permalink)*
chill out, I'm not trying to upset you.
You're stuck on semantics. Move past it, to understanding. "individual" is the word you need to focus on. Like it's neither individual nor arbitrary that we all have the same number of fingers.
So will the world end? No, but it's not convenience but consistency. Not individually, but as a civilization
Anger leads to the dark side
[deleted] · 1 points · Posted at 18:47:17 on January 9, 2016 · (Permalink)*
Please spare me this drivel. The question is about semantics since the beginnings. You can't start arguing about semantics (e.g. by saying "360 still isn't arbitrary") and then when things don't go your way, start speaking like a stoner for unknown reasons and backpedal.
Mrknowitall666 · -1 points · Posted at 18:50:46 on January 9, 2016 · (Permalink)
Get off your high horse
Mrknowitall666 · -1 points · Posted at 18:53:29 on January 9, 2016 · (Permalink)
No, the question was why.
And you're trying to argue to the death of the lameness of arbitrary.
As to going my way, I really don't give a fuck. You're my distraction between 6th grade science questions.
You sound really angry tho.
Mrknowitall666 · 0 points · Posted at 18:57:59 on January 9, 2016 · (Permalink)
So, you'd rather argue that radians is an intrinsic and nonarbitrary system and 360, is arbitrary based on convenience.
[deleted] · 1 points · Posted at 19:04:55 on January 9, 2016 · (Permalink)*
Yes, radians actually are intrinsically defined. For example d/dx sin(x) = cos(x) when x is in radians, but it's something like 180/pi cos(x) when x is in degrees. Similarly exp(x) = 1 + x + x2/2 + ... in radians, with degrees you need a factor pi/180 in front of every x. And so on.
But it's not my freaking point. That radians are intrinsically defined doesn't change the fact that 360° per turn is completely arbitrary.
Mrknowitall666 · 0 points · Posted at 19:14:34 on January 9, 2016 · (Permalink)
Still mad bro? Really consider meditation.
I was suggesting that in contrast to radians, you're saying that degrees are arbitrary.
Because, that wasn't clear before and you're proof further obfuscates your point. So, i guess I have a better understanding of why you're so frustrated.
Stormflux · -2 points · Posted at 18:00:11 on January 9, 2016 · (Permalink)
Then according to you, everything is arbitrary since no reason is ever good enough unless it literally saves the world from ending. Thus, the word loses all meaning.
Arbitrary is a judgement call. Something Reddit has problems with, as evidenced by your comment.
[deleted] · 2 points · Posted at 18:05:01 on January 9, 2016 · (Permalink)
You've never heard of hyperbole before...? I'm done with this shit, believe what you want. I don't care if a few idiots are wrong on the internet.
Stormflux · -1 points · Posted at 18:08:21 on January 9, 2016 · (Permalink)
Ok, when what reason is good enough in order to not be considered arbitrary by you? We've already established that "saving the world" will be a good enough reason, but "divides evenly by many numbers" is not.
So, according to you, we need something that's between those two levels of awesomeness. What if instead of saving the world it just saved a town? Would that be good enough?
How much utility does something have to have before it's not arbitrary?
[deleted] · 1 points · Posted at 18:12:16 on January 9, 2016 · (Permalink)
Are you illiterate? I wrote "I'm done with this shit, believe what you want." What could have made you think I had an interest in continuing this discussion? Look up the definition of necessity if you want, as I said I don't care.
Stormflux · 1 points · Posted at 20:22:22 on January 9, 2016 · (Permalink)
Yeah, my bad. I should have expected that backing you into a corner with no way out except admitting that you're wrong would make you want to be "done" with the conversation.
[deleted] · 1 points · Posted at 07:55:32 on January 10, 2016 · (Permalink)*
Uh? You're sorely mistaken. "Necessity" is not a very complicated word. It means that we couldn't possibly have chosen anything other than 360 to divide the circle. This is obviously not the case, hence it wasn't necessary. Does this get through your skull? I didn't want to stoop to this level of explanation, hence why I didn't want to continue this discussion. If you're still confused, maybe ask another question on ELI5 about the meaning of "arbitrary".
Stormflux · 1 points · Posted at 14:07:16 on January 10, 2016 · (Permalink)
Ok, so... first, something had to "save the world" in order to not be considered an arbitrary decision. Then it turns out "save the world" was hyperbole, and it merely has to be the case that the decision had "no other choice."
Again, I'm not really clear on how much utility a decision has to have before you'll consider it "not arbitrary." Also, your comment is uncivil (ctrl+F skull) and I considered reporting it. Finally, I'm not sure why you're messaging me about this a full day after you said you were done with the conversation.
[deleted] · 1 points · Posted at 14:10:02 on January 10, 2016 · (Permalink)
"A full day" = "11 hours". I was asleep, moron. Time zones, how do they work?!
Stormflux · 0 points · Posted at 14:24:21 on January 10, 2016 · (Permalink)
Awesome. That addresses all of my concerns, and in a civil way with no name-calling at all! Oh wait. No it doesn't.
What I want to know is how much utility something has to have before it's not arbitrary, and 11 hours does not answer that question.
[deleted] · 2 points · Posted at 14:27:05 on January 10, 2016 · (Permalink)
WTF are you talking about "utility"? I mean seriously, open a dictionary, look up what "necessary" means. This is very, very tiring now.
Stormflux · 0 points · Posted at 16:41:04 on January 10, 2016 · (Permalink)
It's only tiring because you're not answering my question.
How much utility must a choice have before you don't consider it an "arbitrary" choice?
If your answer is that the choice must be "necessary" then define necessary. Necessary to what? To saving the world? To my mood? If I make a choice that is necessary for my mood to be satisfied but it doesn't have any rational utility to a reasonable person, than isn't it arbitrary?
[deleted] · 1 points · Posted at 17:09:28 on January 10, 2016 · (Permalink)
http://www.merriam-webster.com/dictionary/necessary
This whole thing could have been avoided had you opened a dictionary.
Stormflux · 0 points · Posted at 17:22:50 on January 10, 2016 · (Permalink)
Not really, because it's still a judgement call, isn't it?
Dividing a circle into 360 degrees is "necessary" if you want to have factors of 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360. This has practical applications because it makes certain kinds of math easier.
Likewise, destroying an asteroid is "necessary" if you want to save the world from an astroid.
But if you don't care about that stuff, then both of those decisions could be said to be "arbitrary."
So again, how much utility is needed, and who defines it?
arnikarian · 3 points · Posted at 10:39:15 on January 9, 2016 · (Permalink)
Eh the entire concept of base 10 maths seems pretty arbitrary to me, base 16 is much... more beautiful.
also: why do programmers confuse Halloween and Christmas; because OCT31 = DEC25
NefariousCat · 13 points · Posted at 11:31:24 on January 9, 2016 · (Permalink)
I'm a fan of base 8 myself, but base 10 isn't arbitrary. It's based on fingers I'm pretty sure.
romulusnr · 10 points · Posted at 12:02:35 on January 9, 2016 · (Permalink)
"Base 8 is just like base 10... if you're missing two fingers."
arnikarian · 1 points · Posted at 12:23:40 on January 9, 2016 · (Permalink)
Well TIL, thanks for that
Kayyam · 1 points · Posted at 13:08:15 on January 9, 2016 · (Permalink)
Mind blown.
thenextbus · 3 points · Posted at 11:49:55 on January 9, 2016 · (Permalink)
Can you explain that?
atte- · 4 points · Posted at 12:07:03 on January 9, 2016 · (Permalink)
Probably just because it goes hand-in-hand with base 2, base 4 (never used), base 8 and so on. It only really makes a difference in computer science where binary (base 2) is used a lot.
[deleted] · 1 points · Posted at 13:04:22 on January 9, 2016 · (Permalink)
When working with computers base 16 would be called Hexadecimal. In Hexadecimal you can use the values 0 - F to represent each "hexit." This makes the hexit F equal the base 10 number of fifteen. What makes hexadecimal so handy for computer science is the fact that it can be converted straight into binary without a lot of overhead arithmetic. Say you have a single byte of data that's represented in binary as 1010 0101. Each group of four bits is a nibble. We know that the 1010 nibble is ten in decimal, and we know that ten is represented as A in hexadecimal. The 0101 nibble is five in decimal and in hexadecimal. Knowing both of these things we can then convert 1010 0101 into the hexadecimal value of A5. We can indicate that this is a hexadecimal value by writing 0xA5. What makes hexadecimal great is the fact that we can use it to represent a large amount of binary information in a human readable form that won't melt your eyes.
atte- · 1 points · Posted at 13:56:38 on January 9, 2016 · (Permalink)
You meant to reply to thenextbus and not me I assume?
risot · 1 points · Posted at 03:39:20 on January 10, 2016 · (Permalink)
Heres a question, if your using base 16 and you put a 0 after a 1 so like 10, would that be considered 16 or 10? If it is considered 10 could this be why we use base 10? As in its closest to base 1.0 in that way.
atte- · 1 points · Posted at 09:46:10 on January 10, 2016 · (Permalink)
10 in base 16 would be 16 in base 10. I think the most likely reason that we use base 10 is that we have 10 fingers.
In computer science, to count in base 16 we start using letters after 9.
Left is base 10, right is base 16 (hexadecimal)
risot · 1 points · Posted at 20:35:08 on January 10, 2016 · (Permalink)
I am still trying to understand this. So in a base 16 system, if you divide 1 in half do you get .5 or something different?
atte- · 1 points · Posted at 20:40:55 on January 10, 2016 · (Permalink)
Hexadecimal is very rarely used with anything other than integers, but you'd get .8.
w2qw · 2 points · Posted at 12:17:04 on January 9, 2016 · (Permalink)
It's nice for programming because computers generally store things in binary and binary and any base 2x system are easily convertible. (0b for binary, 0x for hexidecimal) e.g.:
and the otherway
while
arnikarian · 1 points · Posted at 12:37:31 on January 9, 2016 · (Permalink)
This!
sigma914 · 3 points · Posted at 12:22:14 on January 9, 2016 · (Permalink)*
I'm a fan of base 12
Edit: Balanced Nonary is pretty awesome too.
[deleted] · 2 points · Posted at 11:58:40 on January 9, 2016 · (Permalink)
We have 10 fingers. We count on our fingers, or digits, hence digital.
Some places used base 12 (count the sections on the inside of your 4 fingers with the tip of your thumb, you can go up to 144 if you use both hands)
We don't have a way of counting to 16 on our body as far as i'm aware.
StealthRock · 1 points · Posted at 12:30:43 on January 9, 2016 · (Permalink)
You can count to 1024 easily if you used binary and 10 fingers, and more if you wanted to make things more complicated, which is possible by using more than just an on/off position (and increasing the base of your number system) or by using more body parts (and having more than 10 digits to use).
[deleted] · 2 points · Posted at 12:39:33 on January 9, 2016 · (Permalink)*
Eh. I don't know about easily. It's not exactly an intuitive system usable by pre-literate people to count their cattle or whatever.
WinterPiratefhjng · 2 points · Posted at 13:42:28 on January 9, 2016 · (Permalink)
Hehe. I shall use that joke at work.
toxic181 · 2 points · Posted at 11:14:41 on January 9, 2016 · (Permalink)
And larger the base, better is the approximation.
ScrotumPower · 3 points · Posted at 13:09:29 on January 9, 2016 · (Permalink)
According to that logic, base 12 is better than base 10.
And I have to agree. I suspect the only reason we use base 10 is because of the number of fingers on our hands.
ERIFNOMI · 3 points · Posted at 13:30:05 on January 9, 2016 · (Permalink)
And that's why you see 12 pop up a lot too. 12 inches in a foot, for example. It's easy to measure halves, quarters, thirds, and sixths of a foot. If a foot were 10 inches, the only straightforward divisions are halves and fifths.
ScrotumPower · 2 points · Posted at 14:26:48 on January 9, 2016 · (Permalink)
UK Schools used to teach base 12 (duodecimal). It fell out of favour after computers became a household item, with their use of hexadecimal numbers.
I'm not saying one is better than the other. I'm saying that it's important to teach the concept of non-decimal numbers.
Don't teach the answers. Teach how to ask questions.
ERIFNOMI · 1 points · Posted at 14:30:58 on January 9, 2016 · (Permalink)
I don't see where you said that nor where anyone challenged that stance. I was just providing a common example of base 12.
Best_Towel_EU · 1 points · Posted at 15:04:54 on January 9, 2016 · (Permalink)
Well we also still use qwerty even though it's suboptimal, switching over a system like that isn't easy. I want it to happen though.
romkyns · 1 points · Posted at 16:21:07 on January 9, 2016 · (Permalink)
And it totally is. What a shame about our fingers. Good thing we have two hands and not one, else our base might not have had any factors...
fnybny · 1 points · Posted at 19:22:02 on January 9, 2016 · (Permalink)
Is is unnatural
EGOtyst · 2 points · Posted at 17:09:15 on January 9, 2016 · (Permalink)
It is based on the lunar cycle.
[deleted] · 2 points · Posted at 19:11:35 on January 9, 2016 · (Permalink)
fun fact: it's called a second because it's the second division of the hour (after the minute)
thrasumachos · 1 points · Posted at 16:17:59 on January 9, 2016 · (Permalink)
Also, the reason it's called a second is that a minute is the "first part" of an hour--the first division by 60--while a second is the second division.
Northofnoob · 1 points · Posted at 19:44:32 on January 9, 2016 · (Permalink)
And they used 60 cause they thought there was 360 days in a year.
EtanSivad · 1 points · Posted at 21:43:56 on January 9, 2016 · (Permalink)
First person here to put out the correct answer; Base 60 counting.
brierrat · 17 points · Posted at 16:45:49 on January 9, 2016 · (Permalink)*
There are a lot of interesting reasons listed in these comments... One that is mentioned a lot is because it is divisible by a lot of different factors. But what is missing is why it used to be important for a scale to be divisible by a lot of factors.
Back in the day, to make instrumentation, one had to score the increments by hand. Try this. On a sheet of paper, try marking one edge with exactly 100 marks. You can get the "50" and "25" marks easy enough by dividing in half then in half again. After that, you have to start dividing by five, which is more difficult to do accurately. Now try with 360 marks. Half and half again is 180 then 90. Half again gives you 45. A third of this gives you 15 and a third again gives you 5. Thirds gives you 240, 120. Half these gives you 60, 30, 15, thirds again gives you five before you have to start dividing by five. 5/360 is almost 1/100th of a circumference (.01389 of a circumference). To get similar resolution using base 10 and dividing by only 2s and 3s, you'd need a scale to 1600, with the smallest increment being 25.
So using 360, you can get to a resolution of nearly 1/100th of a circle just by dividing by 2s and 3s and you have easy access to 90 (1/4 circumference), 45 (1/8 circumference), 120 (1/3 circumference), 60 (1/6 circumference) and 30 (1/12 circumference), 15 (1/24 circumference) and 5 (1/72 circumference). Whereas with 100 units, you can get only to quarter circles before you have to figure out how to divide a line into five parts.
This is extremely convenient. In drafting, for instance, you can draw any 15 degree increment just using 30/60/90 and 45/45/90 triangles in combination. And in math/engineering, 30, 45, 90 have convenient degrees to radian conversions.
Xeno_man · 502 points · Posted at 08:09:08 on January 9, 2016 · (Permalink)
Originally it was though that a year was about 360 days, not so much the concept of the earth going around the sun but observing other planets in the sky and the stars. Stars would move from one position in the sky to another and then back again which took about 360ish days. From there a cycle or a circle had 360 degrees.
360 was settled on because it was just so damn divisible. Look at all the factors. 1,2,3,4,5,6,8,9,10,12,15,18,20,24,30,36,40,45,60,72,90,120,180,360.
Now compare that to a number like 100. 1, 2, 4, 5, 10, 20, 25, 50, 100.
Of course today with much more accurate measurements we know a year is closer to 365.25 days.
lucasvb · 320 points · Posted at 12:05:55 on January 9, 2016 · (Permalink)*
As far as I know, this is not entirely correct. Ancient civilizations had pretty accurate astronomy and most knew the year had 365 days and not 360. That's a slightly over 1% error and easy to detect with even crude instruments. Any reasonably large sundial will be accurate enough for checking this.
Last I read about it, Babylonians used a base 60 numeral system, and 360 = 6x60 seemed like a good division system for angles. It was efficient since 60 and 360 have a lot of divisors, and it was also coincidentally close to the number of days, so 1 degree was approximately 1 day.
This eventually carried over for the measurement of time, which is why we have a base 60 hour-minute-second system.
Either way, to be sure OP should ask /r/AskHistorians.
PostalElf · 55 points · Posted at 13:21:27 on January 9, 2016 · (Permalink)
The ancient Mayan Haab calendar is 360 + 5 days: 13 months of 20 days each, followed by 5 "bad luck" days that were left unnamed. So yes, they had a very good grasp of astronomy and definitely knew that a solar year was more than 360 days.
RapedByPlushies · 2 points · Posted at 00:50:16 on January 10, 2016 · (Permalink)
(13 months) x (20 days per month)= 260 days.
So did you mean 18 months of 20 days each, or 13 months of 27.692307... days each?
PostalElf · 1 points · Posted at 04:46:12 on January 10, 2016 · (Permalink)
Oops! I mixed it up with the Tzolkin, which is the 13x20 days one. The Haab is 18x20 + 5. Sorry!
Drews232 · 2 points · Posted at 16:34:26 on January 9, 2016 · (Permalink)
This is more fascinating, how the hell could an ancient civilization figure out a year was 365 days? By looking at stars? But devices to record the accurate position of the stars did not exist?
PostalElf · 5 points · Posted at 17:09:59 on January 9, 2016 · (Permalink)
In contrast to the Tzolkin calendar, which had 260 days and was used by the priests, the Haab calendar was developed by Mayan farmers and was thus significantly more practical. Farmers needed to know how long a year was because they needed to know exactly when to harvest and when to plant.
Fun fact: the ancient Mayans had not two but three calendars! By combining the Tzolkin and Haab dates, you got a unique set of time coordinates for each day that would have been good for the next 52 years. But what if you wanted to make a note of stuff that happened in the last generation, more than 52 years ago? For that, you would use the Long Count calendar. Most ancient Mayan dates would use all three calendars: the Long Count for historical purposes, and the Tzolkin + Haab for everyday purposes.
octopodest · 4 points · Posted at 16:56:47 on January 9, 2016 · (Permalink)
Likely the sun would have been their guide. In the northern latitudes, it's fairly straightforward to count the days between the solstices. There will be one day when the sunrise and sunset occur at their furthest point north on the horizon, and that event is observable without any tools.
Smallpaul · 2 points · Posted at 18:23:03 on January 9, 2016 · (Permalink)
Maybe I spend too much time indoors but if I didn't have maps and globes I can't imagine how I would know what is "the furthest point north". North star, sure, but I know it was picked to be the north star because it pointed north. You needed to discover North first.
MathPolice · 4 points · Posted at 20:36:03 on January 9, 2016 · (Permalink)
Actually, the North Star is pretty special.
It's the only star that doesn't move. Every other star spins around it.
Hour after hour, everything else moves. But the North Star just stays in the same spot.
It would be very obvious to every primitive mind that this is the head honcho star. Not the most bright star, but clearly all other stars are worshipping this one. Or, at least, it is special and different from all others for some reason.
(Before the pedants arrive: yes, the North Star moves very slightly during the night; it's not exactly on the pole.
Before, the ultra-pedants arrive: yes, I know that because the earth wobbles like a top the "North Star" changes slowly over thousands of years and was actually a star called Thuban back in Ancient Egyptian times. Today it's Polaris. In a few thousand years it will be Vega.
Fun fact: right now (give or take a few years) Polaris has moved as close to the pole as it will ever ever get, and Earth is wobbling away from it on a long slow voyage to eventually point at Vega instead.)
Thootom · 1 points · Posted at 18:57:00 on January 9, 2016 · (Permalink)
The sun rising in the east would have been what they used for orientation before they discovered the magnetic north. That's actually why Europe is "the west" and Asia is "the orient".
cockOfGibraltar · 1 points · Posted at 21:06:32 on January 9, 2016 · (Permalink)
The sun is your guide. You pick a point to stand the watch it's rising and setting move north and south. That's how you define north south east and west. Make sense?
octopodest · 1 points · Posted at 23:53:20 on January 9, 2016 · (Permalink)
Well, you don't need to know anything about "north" to know that the sunrise slides along the horizon as the seasons change. Then at some point in the summer, it starts sliding back down the way it came until it's winter again.
Trust me, if you didn't have anything to do but watch the sky, you'd catch on pretty quick.
zzzKuma · 3 points · Posted at 17:07:31 on January 9, 2016 · (Permalink)
Day length. The summer and winter solstice are very noticeable and regular.
MathPolice · 1 points · Posted at 20:10:28 on January 9, 2016 · (Permalink)
In addition to the solstice others have mentioned, they also used a thing called the Heliacal Rising of various important stars to determine the length of the year and determine important dates.
Here's how it works (using Sirius as my example star).
One day you wake up before sunrise and look for Sirius. You never see it. Same story the next day. And the next.
Then one day... BOOM! you see Sirius rise shortly before the sun comes up and washes it out. Alright! Today is Sirius Day, baby!
And every day after that, Sirius will rise even a bit more before the sun. So if you got clouded out for a day or two, you can still figure it out because you'll see it the next day.
Each "important" star (they used about 10 or so) indicates a particular important day of the year.
For example, the Heliacal Rising of Vindemiatrix meant "it's time to harvest the grapes" to the Ancient Greeks! (TMI on Vindemiatrix)
cockOfGibraltar · 1 points · Posted at 21:05:08 on January 9, 2016 · (Permalink)
They made them. Basic metal and or wood working and a lot of free time and you too could figure it out. The pirate observations where probably a simple procession of the sunset past landmarks and the people started recording the procession as accurately as they could. If you use larger objects as instruments then your accuracy can be increased too. It would be really easy to move a make shift sextant one minute of it was 100 meters across
wokcity · 74 points · Posted at 12:39:16 on January 9, 2016 · (Permalink)
60x60=3600
lucasvb · 12 points · Posted at 13:45:34 on January 9, 2016 · (Permalink)
Whoops. Fixed.
uber1337h4xx0r · 1 points · Posted at 21:20:16 on January 9, 2016 · (Permalink)
I made that mistake in chemistry class when figuring out how many seconds in an hour. :(
Noobivore36 · -16 points · Posted at 12:54:37 on January 9, 2016 · (Permalink)
This
[deleted] · 3 points · Posted at 12:31:30 on January 9, 2016 · (Permalink)
is it the mark of a "good" base that it has lots of divisors?
InaneSloth · 40 points · Posted at 12:48:43 on January 9, 2016 · (Permalink)
A base with more divisors will generally be easier to calculate with than one with fewer divisors. So in a sense, yes
yanroy · 2 points · Posted at 17:10:57 on January 9, 2016 · (Permalink)
This is why carpenters often prefer using inches even in metric areas (I know this is true in Canada, not sure about the rest of the world).
[deleted] · -1 points · Posted at 13:04:39 on January 9, 2016 · (Permalink)
base 2 versus base 6.
SeattleBattles · 19 points · Posted at 13:40:53 on January 9, 2016 · (Permalink)
Think about needing to calculate 1/6 of a circle.
If you assume 100 units, then you get 16.666666666....
That's certainly not an impossible number to work with, but it certainly makes doing calculations much much harder. For example if you wanted to multiply that by 4, or divide again by 6. Certainly not something most people could do in their head, and even with writing it down it would be challenging to people without training.
If, on the other hand, you assume 360 units. Then that problem is easy. Divide by 6 and your get 60. Divide again and you get 10. Multiply by 4 and you have 240. Calculations most people could easily do in their head, or simply memorize.
That's a real big plus when you don't have calculators or even easy access to writing.
lucasvb · 4 points · Posted at 13:47:32 on January 9, 2016 · (Permalink)
It just simplifies notation because common fractions have terminating decimal representations. For instance, 1/3 is super common but we have to write it as 0.333..., which sucks. In base 12, for instance, 1/3 = 0.4
GlyphGryph · 5 points · Posted at 14:23:09 on January 9, 2016 · (Permalink)
Yeah, it's the whole reason for western measurement - ever base used is easily divisible with a minimum of numbers. 12 inches in a foot means that you can have half a foot (6"), a third of a foot (4"), a quarter of a foot (3"), and a sixth of a foot (2") as whole numbers that are easy to add together.
Base 16 is really great if you have to split things in half a lot (like in computer science), since you can go 8/4/2/1. But it's larger than base 12 for the same number of divisors.
Metric (base-10) is probably the worst possible base, and has no redeeming use qualities that I am aware of aside from people having 10 fingers making it convenient to count on your fingers, which is... not a great justification, and it sucks that we got stuck with such a crappy base system. 12 or 16 would have been way better.
Walter_ORielly · 2 points · Posted at 13:33:15 on January 9, 2016 · (Permalink)
Depends upon what your definition of good is. Binary logic is Base 2. That's a good one and 2 is a prime
ginkomortus · 1 points · Posted at 17:04:44 on January 9, 2016 · (Permalink)
Sure it's prime, but 2 is also divisible by all positive integers =< to itself, so pbbbt.
KisarOne · 1 points · Posted at 14:16:53 on January 9, 2016 · (Permalink)
There are many old units for weights and lenghts and so on which are based on 12. That makes it quite easy to calculate because 1/3 and 1/4 are nice numbers in base 12.
ShelfordPrefect · 1 points · Posted at 16:11:14 on January 9, 2016 · (Permalink)
Some people argue that it works be easier if we used base 12, because it divides by 2, 3 and 4 nicely. The 3 times table would then go 4,8,10,14,18,20,24...
Smallpaul · 1 points · Posted at 18:26:15 on January 9, 2016 · (Permalink)
Think about a protractor designed around 360 degrees:
https://en.wikipedia.org/wiki/Protractor
You can use that to slice a pizza into basically 1, 2 , 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40 slices. That's a lot of flexibility.
TheRealArtVandelay · 2 points · Posted at 14:42:19 on January 9, 2016 · (Permalink)
This is basically what I have heard as well. I read a pretty in depth article about it a few years back but can't seem to find the link. Is basically said that the Sumerians/Babylonians, who were quite adept at geometry, saw the angle that is now 60 degrees as being especially significant due to its radius being equal to its secant line, and being equally divisible within a whole circle. Because they had a number system that only went up to 60 unique characters, they divided that special angle into 60 pieces (degrees). Since there are six of this angle in a whole circle, a circle would therefor have 360 total degrees. The stuff about there being close to that many days in a year is mostly coincidence, as astronomy was good enough then for them to be more accurate with that.
bobsterman · 1 points · Posted at 13:04:35 on January 9, 2016 · (Permalink)
60x6 is 360, not 60x60
lucasvb · 2 points · Posted at 13:42:34 on January 9, 2016 · (Permalink)
Whoops. Corrected. I was carried over with the degrees-minutes thing.
[deleted] · 1 points · Posted at 13:34:27 on January 9, 2016 · (Permalink)
Maybe in your crazy non-Babylonian math!
tbirdtank · 1 points · Posted at 14:02:30 on January 9, 2016 · (Permalink)
Correct except I'm not sure they picked 360 because it's easily divisible. I think its more because circles weren't promenent back then. Instead they studied hexagons. 6 x 360
Badgerfest · 1 points · Posted at 14:27:12 on January 9, 2016 · (Permalink)
Don't forget to check the /r/AskHistorians FAQ.
[deleted] · 1 points · Posted at 15:05:18 on January 9, 2016 · (Permalink)
Base 60!?
Have you seen anything incoded in base 64? I can't imagine trying to do math on my hands or in my head with something like that.
lucasvb · 2 points · Posted at 15:08:23 on January 9, 2016 · (Permalink)
It's not that difficult to work on larger bases, especially one with a lot of divisors. The bigger issue is probably memorizing the symbols, but you can get around that by making their value self-evident.
Here's how they wrote numbers.
[deleted] · 1 points · Posted at 15:29:21 on January 9, 2016 · (Permalink)
What. That shouldn't count. 10 has a different symbol than 1. And there's nothing stopping them from going to 61 or more using this same pattern.
lucasvb · 2 points · Posted at 15:32:09 on January 9, 2016 · (Permalink)
Why shouldn't it count?
Would it really be different if we simply replaced the symbols 0-9 with a circle with that many dots inside?
Having the symbols be separate entities and distinct is all that is necessary for positional number systems to work.
[deleted] · 1 points · Posted at 15:48:24 on January 9, 2016 · (Permalink)
I mean using their system, there's no reason whatsoever to stop at 60. 1s get grouped up to 10. So 10s should be able to be grouped up to 100. Then a new symbol could be used for 100...
lucasvb · 4 points · Posted at 15:56:13 on January 9, 2016 · (Permalink)
Well, there are good reasons to stop at 60. Good number bases are a product of the smaller numbers, which occur often.
In general, the property you're looking for is what describes a highly composite number.
60 divides 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60.
Using anything larger wouldn't be very beneficial, until you have a factor of 7 in the mix. But then you're already at least at 420.
Mrknowitall666 · 1 points · Posted at 15:59:19 on January 9, 2016 · (Permalink)
This is correct, according to my son's 6th grade world history text book.
But you should take my comment with a grain of salt, because we live In Florida
gualdhar · 1 points · Posted at 16:54:21 on January 9, 2016 · (Permalink)
Interestingly, Babylonians got to base 60 by using their fingers, just like we got to base 10 by using them. They would tick off the phalanges (finger bones) on their right hand with their thumb - so the index would be 1-3, middle 4-6, ring 7-9, pinky 10-12. When they got to 12, they'd extend a finger on their left, like how we count. That got them to 60 with just two hands.
maahhkus · 1 points · Posted at 18:48:36 on January 9, 2016 · (Permalink)
From what I understand, the origins are in the base 60 numeral system of the Babylonians.
But you are both sort of right about the year. The ancient Egyptians had a 360 day year, but they knew that an astronomical year was 365 days. So they had a 5-day drunken festival in between each calendar year to keep it all accurate.
I say we adopt this now. 12 30-day months and a yearly 5-day shitshow.
OFF_THE_DEEP_END · 1 points · Posted at 19:00:00 on January 9, 2016 · (Permalink)
They knew it had 365 but they still altered their calendar to have 360. The same way we know the year is actually 365.25 days, but we just settle on 365 and tack on a day every four years.
The ancient people just tacked on 5 days when the ruling elite decided they needed to have an event to honor the gods.
atomfullerene · 1 points · Posted at 19:08:43 on January 9, 2016 · (Permalink)
They knew the solar year was more than 360 days, but that doesn't mean they wouldn't have "rounded" a bit to use the circles.
I strongly suspect the "base 60" system came about because of the 360 degree circle, not the other way around.
cockOfGibraltar · 1 points · Posted at 21:01:24 on January 9, 2016 · (Permalink)
It's probably some of both. If you choose to use days as your inspiration you might end up choosing 360 instead because it's easier to work with
Awkward_moments · 0 points · Posted at 12:16:11 on January 9, 2016 · (Permalink)
That's what I read. My maths teacher basically said he made a guess about 360 being based on the days in the year, so I got home looked it up and Babylonians was the answer I found.
[deleted] · 2 points · Posted at 13:03:54 on January 9, 2016 · (Permalink)
Those people used electric lanterns, legends say.
[deleted] · 24 points · Posted at 10:24:46 on January 9, 2016 · (Permalink)*
That is a cool idea.
We could have developed "days" and "months" as degree units.
"This angle is 3 months long"
"All triangles angles summed up are 6 months long".
Perhaps even Way more visual, less abstract, for school pedagogy purposes.
Edit: corrected mathematical perspective
Sparkybear · 29 points · Posted at 10:30:08 on January 9, 2016 · (Permalink)
Well longitude is broken up by minutes and correspond to time zones. 60 minutes is the width of each time zone and each minute, should, line up to a one minute offset of time from it's neighbors.
[deleted] · 8 points · Posted at 11:52:25 on January 9, 2016 · (Permalink)
Do you mean that every neighbourhood could enjoy a different time zone?
We could use this advancement to throw shit on our neighbours: "no wonder you don't agree with me, your life is literally retarded with respect to ours"
romulusnr · 12 points · Posted at 12:01:34 on January 9, 2016 · (Permalink)
That is in fact how time was told before the advent of the railroad. Particularly via sundials. But also in that you would set your watch/clock based on whenever the sun was at its highest point / shadows were shortest, and make that noon.
[deleted] · 3 points · Posted at 13:35:14 on January 9, 2016 · (Permalink)
"You might think that, being back in the past, but here in the future we know you go and fuck yourself now."
[deleted] · 3 points · Posted at 17:25:21 on January 9, 2016 · (Permalink)
Maybe I don't understand you correctly, but longitude is broken up into degrees (180 West, 180 East, 360 in total). One degree has 60 (arc)minutes.
All these minutes have nothing to do with time zones. (a 'natural' timezone would have 360/24=15 degrees of longitude - but their exact distribution is often based on economical and political reasons).
source: navigated a sailing vessel.
MathPolice · 2 points · Posted at 21:15:52 on January 10, 2016 · (Permalink)
If you've navigated a sailboat using Celestial Navigation (uncommon in these days of GPS) then you've heard of Right Ascension.
Right Ascension is basically the equivalent of longitude projected onto the sky (to locate guiding stars) -- but it is not measured in degrees! Instead it is in hours, minutes, seconds. So you wouldn't say "180.5 degrees," you'd instead say "12 hours, 2 minutes, 0 seconds."
Sparkybear · 1 points · Posted at 19:06:50 on January 9, 2016 · (Permalink)
Seems like there is a correlation between the two by my initial understanding between the two.
Mrknowitall666 · 1 points · Posted at 16:06:46 on January 9, 2016 · (Permalink)
Which is convenient especially for sailing ships... Nautical miles right down to fathoms is done in rads, basically, as the earth is basically round.
thrasumachos · 1 points · Posted at 16:16:46 on January 9, 2016 · (Permalink)
Huh, TIL why they use minutes.
twsmith · 1 points · Posted at 12:39:46 on January 9, 2016 · (Permalink)
The minutes of longitude are different from minutes of time.
1 day = 24 hours = 1440 minutes.
1 revolution = 360 degrees = 21600 minutes.
MasterUnlimited · 1 points · Posted at 14:00:14 on January 9, 2016 · (Permalink)*
But there are 15 time zones. 21600/15 = 1440
There is a direct correlation between longitude and time. It is called arc time. I'm not really sure how to explain this, in this context so I'll just leave this.
http://aviationtheory.forumotion.net/t8-time-arc-conversion
EDIT: sorry for the wrong information. But the link is valid.
Caraes_Naur · 2 points · Posted at 19:54:02 on January 9, 2016 · (Permalink)
There are 24 time zones, each of 15 degrees.
MasterUnlimited · 1 points · Posted at 14:57:39 on January 10, 2016 · (Permalink)
Ah crap yeah I got it backwards. Oh well. I put the link up that would be better at explaining it than I could.
[deleted] · 2 points · Posted at 11:38:18 on January 9, 2016 · (Permalink)
[deleted]
[deleted] · 1 points · Posted at 11:48:50 on January 9, 2016 · (Permalink)
Well I respects your opinion. /s
bugi_ · 2 points · Posted at 16:02:49 on January 9, 2016 · (Permalink)
Interestingly in astronomy distances in the celestial sphere are measured in degrees divided into minutes and seconds. E.g. 2° 11' 40'' for 2 degrees 11 arcminutes and 40 arcseconds.
KuntaStillSingle · 2 points · Posted at 16:50:13 on January 9, 2016 · (Permalink)
"The sum of angles in every triangle is 182.5 days or 4 thirty-day months, plus 2 thirty one day months, plus 1/2 day."
365 subdivisions of a circle isn't really that intuitive a system for probably most math applications.
droomph · 2 points · Posted at 11:08:44 on January 9, 2016 · (Permalink)
I'll have a baby in pi radians!
no1_vern · 1 points · Posted at 15:05:02 on January 9, 2016 · (Permalink)
I'm thinking a hospital would be better.
F_Klyka · 0 points · Posted at 17:34:55 on January 9, 2016 · (Permalink)
So, you're Pi/2 radians in? It hardly shows!
Doublution · 1 points · Posted at 12:36:22 on January 9, 2016 · (Permalink)
We have minutes and seconds, but that's a little bit more specific than what you said.
just-casual · 11 points · Posted at 12:24:47 on January 9, 2016 · (Permalink)
And we made our week SEVEN DAYS LONG? Morons.
megane-kun · 15 points · Posted at 15:22:46 on January 9, 2016 · (Permalink)*
That is because of the month, isn't it?
If today's a new moon, a week later it'd be a half-moon. Another week, it'd be a full moon. Yet another week, it'd be a half-moon again. And again another week, and it's a
fullnew moon again.... Not exactly, but it's good enough back then, I guess?
Thor_Odin_Son · 1 points · Posted at 16:42:51 on January 9, 2016 · (Permalink)
You're missing quarter moons haha, under your model blue moons wouldn't be terribly rare.
megane-kun · 2 points · Posted at 17:09:43 on January 9, 2016 · (Permalink)*
Eh?
I did a quick check at wikipedia and confirmed I was more or less on point.
First quarter is the half-moon (50% of the moon is lit) right after a new moon. Similarly, the third (or last) quarter is a half-moon right after a full moon.
Also, blue moons are due to the length of the month (28 to 31 days) not really being equal to the length of the moon's orbit around the earth (~29 days), right? It's still possible even if the moon's orbit is exactly 28 days. If January 1 is a full moon, January
2829 would be a blue moon, the 2nd full moon of the month.EDIT: Off-by-one error (January 28, instead of January 29)
Thor_Odin_Son · 1 points · Posted at 17:15:02 on January 9, 2016 · (Permalink)
Ya know what it was that confused me? You went from full moon to half moon to full moon again, and I knew that was off, my correction was just inaccurate.
megane-kun · 1 points · Posted at 17:16:27 on January 9, 2016 · (Permalink)*
It's okay~ ;) I was a bit confused too.
EDIT:
OH. THAT ONE. /facepalm.
just-casual · 0 points · Posted at 15:48:11 on January 9, 2016 · (Permalink)
I know lol I was /s
megane-kun · 0 points · Posted at 16:31:27 on January 9, 2016 · (Permalink)
My bad ^_^
just-casual · 0 points · Posted at 16:45:07 on January 9, 2016 · (Permalink)
No harm, no foul :)
F_Klyka · 2 points · Posted at 17:36:20 on January 9, 2016 · (Permalink)
Let's fuck with people and only use prime bases for everything!
just-casual · 2 points · Posted at 18:31:51 on January 9, 2016 · (Permalink)
HAHAHAHAH I love it. Is a prime base even possible? I'd think one major issue would be how slowly it would accelerate (LOTS of zeroes after numbers), right?
MathPolice · 1 points · Posted at 16:47:36 on January 10, 2016 · (Permalink)
Sure. It's easy to make prime bases like 3 or 5 or 7 or 11.
In fact binary is actually a prime base (base 2).
Here's counting in base 3:
0, 1, 2, 10, 11, 12, 20, 21, 22, 100, 101, 102, 110, 111, 112, 120, 121, 122, 200, 201, 202, 210, 211, 212, 220, 221, 222, 1000, 1001, ...
So in base 3 the numbers get "long" much sooner than with our regular base-10 counting, but in base-11 or base-13 the numbers would grow more slowly. (That is, fewer zeroes after big numbers.)
Best_Underacheiver · 1 points · Posted at 03:59:54 on January 10, 2016 · (Permalink)
pretty sure seven days comes from seven heavenly bodies - seven god's names, i've used spanish here instead of latin figuring they would be more familiar to you : sun - sunday, domingo (Lord's day) : moon - monday, lunes : mars - tuesday (tieu=germanic war god, mars is roman war god), martes : mercury - wednesday (woden=odin) , miércoles : jupiter - thursday (thor), jueves (jove=jupiter) : venus - friday (frigg), viernes : saturn - saturday, sábado (sabbath)
http://spanish.about.com/od/historyofspanish/a/names_of_days.htm http://ancienthistory.about.com/od/socialculture/a/120709dieshebdomadis.htm
[deleted] · 1 points · Posted at 13:36:48 on January 9, 2016 · (Permalink)
We didn't do that, son. American God did.
just-casual · 3 points · Posted at 13:54:31 on January 9, 2016 · (Permalink)
Ah right, Catholic school obviously worked on me.
LaughingTachikoma · 5 points · Posted at 10:17:03 on January 9, 2016 · (Permalink)
If I remember my astro class correctly, we can see the length of a year even more simply than that by just looking at the time it takes for the sun to cycle from its highest to lowest points and back again. Though I'm not entirely sure that had any bearing on the use of 360 in circles...
BrowsOfSteel · 7 points · Posted at 11:59:48 on January 9, 2016 · (Permalink)
You’re talking about a tropical year, Xeno_man is talking about a sidereal year. They differ in length by about twenty minutes (not five days; 360 divisions is a rough approximation for either).
Our calendar is a solar calendar. The winter solstice will forever fall on or near December 22, and so on. Thus the seasons are fixed.
However, if your calendar fixes the seasons, it cannot also fix the stars. They only drift by about 0.014°, or 50 seconds of arc per year, but give it a few centuries or millennia and it becomes significant.
KurrKurr · 1 points · Posted at 12:04:44 on January 9, 2016 · (Permalink)*
365.2425 days.
((365 * 4 + 1) * 100 - 3) / 400 = 365.2425
mattdan79 · 1 points · Posted at 13:02:38 on January 9, 2016 · (Permalink)
I believe time was based on 60 for this exact reason too.
[deleted] · 1 points · Posted at 13:46:55 on January 9, 2016 · (Permalink)
[deleted]
The_camperdave · 1 points · Posted at 16:39:06 on January 9, 2016 · (Permalink)
No. Not at all. The shape of a planet has nothing to do with the duration of its orbit.
ginkomortus · 1 points · Posted at 16:55:51 on January 9, 2016 · (Permalink)
Nope. The orbit of the Earth and the length of the day are not directly related. That we have a number of days close to a useful number for dividing circles is lucky, if OP's Babylonian astronomer story is true. (I am not a
lawyerhistorian, but I don't think there's a definite answer. That story smacks of the "Oh, look at the adorably ignorant ancient people trying their best" narrative though.)Good question, though! Wanna know something cool about orbits and math, though? The square of a planet's period, the time it takes to go around the Sun, divided by the cube of it's distance from the Sun gives you some ratio, right? Well, that ratio is the same for any planet orbiting the same star. (Or satellite orbiting anything, like the Moon and the ISS around Earth.) So, knowing the Martian year is about 1.88 times as long as an Earth year, how much farther away is Mars from the Sun?
[deleted] · 1 points · Posted at 13:56:24 on January 9, 2016 · (Permalink)
Nah, it was because the Babylonians counted in sets of 60.
Denziloe · 1 points · Posted at 14:52:08 on January 9, 2016 · (Permalink)
-> Make up an answer with no sources
-> Hundreds of upvotes
-> ELI5
timfriese · 1 points · Posted at 15:36:08 on January 9, 2016 · (Permalink)
Absolutely, I believe there must be a connection between 365 days in a year (which is an accident) and the resulting human imposition of 360 degrees in a circle.
ivanwarrior · 1 points · Posted at 16:50:21 on January 9, 2016 · (Permalink)
Hey the year is still 360 days if you're an accountant.
Xaxxon · 1 points · Posted at 18:03:12 on January 9, 2016 · (Permalink)
Do you have a source on any of that?
Dinosaur_Boner · 1 points · Posted at 19:44:51 on January 9, 2016 · (Permalink)
It actually is related to a year. Take the number of feet around the equator and divide by the number of days in a year. Divide again by 1000 and you get 360.
fonzanoon · 1 points · Posted at 00:36:48 on January 10, 2016 · (Permalink)
I, for one, believe we should strap a giant rocket to China, pointing outward. We ignite the rocket at noon in China, causing the earth's orbit to slow down just enough to reduce our year to 360 days for the sake of convenience.
Nothing can go wrong with this plan.
dNitza · 0 points · Posted at 11:30:51 on January 9, 2016 · (Permalink)
So does that mean when we up and move to Mars, we will need to redefine a circle as having ~668 degrees?
makka-pakka · 1 points · Posted at 11:58:06 on January 9, 2016 · (Permalink)
Isn't Mars's period 668 Earth days? We'd have to redefine it as however many Martian days in a Martian year.
Actually looking it up, a Martian day is only about 1/2 an hour longer than an Earth day. Didn't expect them to be so close given the size differential.
vezance · 1 points · Posted at 13:28:33 on January 9, 2016 · (Permalink)
I don't think there is any causal relation or even correlation between the size of a planet and its rotational period. Size wouldn't matter.
makka-pakka · 1 points · Posted at 13:42:10 on January 9, 2016 · (Permalink)
I was basing this on a quick look at this table and didn't give it much thought. Gas giants are spinning hella fast, and the smaller planets slower than Earth. You're probably right that there's other factors involved, or else Venus wouldn't have a 243 day rotation.
vezance · 2 points · Posted at 13:51:32 on January 9, 2016 · (Permalink)
(I could be wrong) If I recall correctly, the rotational periods of all planets were decided at their formation, based on the conditions under which they were formed. Sometimes they gained/lost speed after being hit by asteroids. Additionally, they all lose speed over time (earth is also slowing down).
Edit: Not to take this too offtrack, but I know an expert on this - /u/Astromike23. Maybe if he sees this he might add more insight.
Adeus_Ayrton · 9 points · Posted at 17:39:41 on January 9, 2016 · (Permalink)
You could divide a circle into as many regular parts as you wish. One of the reasons 360 is so convenient is because it's the smallest number divisible by all single digit numbers except 7.
blbd · 5 points · Posted at 19:01:11 on January 9, 2016 · (Permalink)
The 360 was arbitrary but intentionally arbitrary. It was before they had calculators by hundreds of years. So the mathematicians and geometers picked a value evenly divisible by many commonly used smaller numbers such as 1 2 3 4 5 6 8 9 10 and 12.
1337ndngrs · 5 points · Posted at 22:31:44 on January 9, 2016 · (Permalink)*
It is relatively arbitrary, but one benefit of 360 over 100 is number of factors.
360: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180, 360
100: 1, 2, 4, 5, 10, 20, 25, 50, 100
Edit: To provide an example, what's 5/6 of a circle in degrees? Using the 100 degree method, it's 83.333... . Using the 360 degree method, it's 300 degrees, a much more friendly number to work with.
[deleted] · 8 points · Posted at 19:58:31 on January 9, 2016 · (Permalink)
Every metric is essentially arbitrary. But they are chosen by people because of their usefulness.
There are other measurements for circles, and are used depending on applications, but the reason the 360° metric is most common is because with it a circle is easily divided into parts that are whole numbers. A circle measured in degrees is easily divided by 2,3,4,5,6,8,9,10... And you don't get any fractions. Its a large number because it enables you to further divide those portions equally as well and still have whole number measurements.
It is this same reason that a day is divided into 24 hours of 60 minutes and 60 seconds. A day can be easily divided into 86400 seconds, 1440 minutes, and all of those numbers can be easily divided by 2,3,4,5,6,8,9,10,12,15,16,18,20... And you'd still get at the very least a whole number of seconds in each.
_AndrewC_ · 0 points · Posted at 21:33:10 on January 9, 2016 · (Permalink)
(They're not all arbitrary - radians is essentially inescapable once you do calculus on sin cos and tan - only when you use radians does y=sinx differentiate to y=cosx etc.)
[deleted] · 1 points · Posted at 22:25:01 on January 9, 2016 · (Permalink)
Well radians are based on measurements of a circle (1 rad is the angle formed in a segment of a circle where the circumference equals the radius, 1:1ratio of r and c gives you 1 rad) so of course they are going to demonstrate a naturally occurring component of one. But the metric itself is still arbitrary (for example, if D was used instead of r to form the measurement, the full circumference would be equal to pi, not 2pi). Like I said the metrics are created because they are useful.
_AndrewC_ · 1 points · Posted at 03:15:07 on January 10, 2016 · (Permalink)*
Edit: TL;DR: Your way would break calculus, which is why we need to use radians, as I perhaps didn't emphasise properly, sorry.
Detail:
Your response suggests I may not have emphasised the calculus bit strongly enough, as you seem to have missed that bit. If you define it that way, then when you differentiate y = sin x, you will get 2 cos x, not cos x, and a whole lot of very nice maths will suddenly get needlessly much more complicated.
All measurements of angle are arbitrary, yes, until you get to calculus. You have to use radians unless you want calculus to work differently.
This paragraph edited to expand : If you don't use radians, you either have to redefine sin to not be the y coordinate on the circle x2 + y2 = 1 of a point at that angle, or give up on differentiating sin x to get cos x. Radians are the only way you can measure angles where sin x differentiates to cos x.
Radians aren't there because they're nice, they're inescapably there because they work.
[deleted] · 8 points · Posted at 07:56:19 on January 9, 2016 · (Permalink)
[deleted]
ScrotumPower · 0 points · Posted at 13:22:59 on January 9, 2016 · (Permalink)
Bah. When I was young...
smpl-jax · 8 points · Posted at 14:57:55 on January 9, 2016 · (Permalink)
360 is the best because there are so many divisions you can have, like crazy many
180 - 2; 120 - 3; 90 - 4; 72- 5; 60 - 6 ; 45 - 8; 40 - 9; 36 - 10 and many more
kharneyFF · 1 points · Posted at 16:29:52 on January 9, 2016 · (Permalink)
So 360 is kinda the lowest number wholly divisible by the the most numbers?
Kalmathstone · 1 points · Posted at 17:44:26 on January 9, 2016 · (Permalink)
Kinda, yes. It's a highly composite number. 240 and 720 are the closest alternatives.
kharneyFF · 1 points · Posted at 18:34:06 on January 9, 2016 · (Permalink)
I like 240 better, lets use that.
smpl-jax · 1 points · Posted at 17:56:00 on January 9, 2016 · (Permalink)
In laymans terms, yes
fnybny · 1 points · Posted at 19:23:53 on January 9, 2016 · (Permalink)
Why are you using a dash to denote multiplication... Better yet just show the natural factorisation
smpl-jax · 1 points · Posted at 19:42:17 on January 9, 2016 · (Permalink)
Easier to type
retry-from-start · 1 points · Posted at 01:40:30 on January 10, 2016 · (Permalink)
If you're doing calculus, using radians (2π) is far, far superior to degrees (360).
marconis7 · 3 points · Posted at 19:03:08 on January 9, 2016 · (Permalink)
Babylonians liked 60 for calculations. Probably because it can be divided evenly by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30. So many practical, fractional portions aren't too difficult. And as a result, we still use 60 secs, 60 minutes, 60x6 degrees for angles which allows even more subdivisions.
Clare47 · 1 points · Posted at 10:58:23 on January 10, 2016 · (Permalink)
My understanding is that the babylonians used 60 because of the counting system they used with their fingers, instead of counting with each finger (for a total of 10) they counted the space between each knuckle on one hand (not including thumb, for a total of 12) and kept track of the number of twelves with the other hand. Five twelves are 60. This is how I understand we got the 12's and 60s in current measurements (seconds, minutes, hours, feet, inches, degrees etc). That may not be 100% accurate as it's just my understanding, the counting system is real for sure though.
marconis7 · 1 points · Posted at 18:55:53 on January 10, 2016 · (Permalink)
That's so cool. I never knew that angle. Early "digital" information processing. Thanks.
geppetto123 · 3 points · Posted at 21:13:20 on January 9, 2016 · (Permalink)
No, it's not arbitrary against most comments here. It was wisley chosen and is a special number just like 60 or 24 on the clock. The idea is that 360 has 24 divisiors which end up in integer number without decimals. The much larger number 1000 for example has only 12 integer divisiors and would be unpractial. I can't recall the mathematical name for this special numbers. As far as I remember it was the Mayas who used this reasoning.
bicyclemom · 3 points · Posted at 18:48:35 on January 9, 2016 · (Permalink)
You've hit on one of my pet peeves. This is probably my biggest complaint of how trigonomentry is taught (at least how it was taught to me many years ago).
They should not even bother with degrees until they first go over radians. Radians is essentially measuring the circle as a unit of PI.
It is SOOOO much easier to deal with radians in trig than degrees.
360 has a lot to do with the Babylonians and the fact that there were roughly 360ish days in a year. So, not exactly arbitrary, but historical.
sdb2754 · 3 points · Posted at 21:05:51 on January 9, 2016 · (Permalink)
Yes. Degrees are arbitrary. Radians are not, though. Radians relate the arc length to the angle. c = r*theta.
I guess this is the typical problem in measurements. A system in place is difficult to change. Radians make more sense, but most non-tech people will continue to use degrees.
docbauies · 3 points · Posted at 23:48:36 on January 9, 2016 · (Permalink)
The nice thing about 360 is it is easily divisible by 1,2,3,4,5,6,10,12,15,20,30,40,60,120,180.
100 gets 1,2,4,5,10,20,25,50
Shewhoisgroovy · 5 points · Posted at 10:58:56 on January 9, 2016 · (Permalink)
I've heard that 360 was chosen because it has so many factors, thus making it easily divisible by lots of other numbers
AncillaryHobbit · 2 points · Posted at 14:33:14 on January 9, 2016 · (Permalink)
You can divide any number by any other number. 360 is divisible, without remainders, by more numbers than 100 is.
semiloki · 2 points · Posted at 15:17:06 on January 9, 2016 · (Permalink)
Sure. You can divide a circle any way you want. We use 360 degrees for a few reasons. Partially it is because it is a multiple of 12. 12 is a nice number because it is evenly divisible by so many numbers. You can divide it by 2,3,4, and 6. 10, on the other hand, can only be divided by 5 and 2. So, twice as many potentials for an even fraction. But since 360 is also a multiple of 10 you get to divide it by 5 as well.
360 evenly divides by so many numbers it just makes the math easier.
Bu the same can be said for any combination of 5 and 12. You get a lot of nice and easy to work with fractions with 60. So why 360?
A big reason is the orbit of the Earth. We have 365 days a year. We've known this for centuries. If we say a circle is 360 degrees then working out how much of an arc the Earth moves in it's orbit for a given period of time is dirt simple.
It moves about a degree a day.
unabiker · 2 points · Posted at 15:17:45 on January 9, 2016 · (Permalink)
In the time before CNC machines, industry used machines called automatic screw machines. Instead of computer control, the machine was controlled by cams and wheels that made the machine do certain functions during the cycle. The wheels were divided in to 100 segments, which makes the math necessary to "program" the machine much easier. So instead of degrees, we would talk in terms of "huns."
websnarf · 2 points · Posted at 15:35:48 on January 9, 2016 · (Permalink)*
The ancient Babylonians used a base-60 system in which each digit was subdivided into 6s and 10s. In this case 360 = 6 x 60. This convention may be based on 6 equilateral triangles joining in a hexagon around a point.
It is, of course, otherwise just a matter of convention. The most pure unit is radians (a full circle is 2*PI), which maps the degrees to length of the arc of a unit circle.
basaltgranite · 2 points · Posted at 17:07:12 on January 9, 2016 · (Permalink)*
Arbitrary but rational. The use of 360 for circles/time/geography goes back to Mesopotamia. Base 60, called sexagesimal, is convenient if you prefer to avoid fractions, because 60 is evenly divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60. Three hundred sixty is a multiple of 60 and further divisible by 8, 9, 16, 18, etc. It's also close to the number of days in the year, especially if you're willing to count the year as 360 days plus ~5 intercalary days.
[deleted] · 2 points · Posted at 17:07:47 on January 9, 2016 · (Permalink)
Sort of on Topic: It also came from the days in one year, but 365 is not divisible easy, while 360 can be divided into many factors.
someperson99 · 2 points · Posted at 20:05:49 on January 9, 2016 · (Permalink)
wow, 2 years of high school suffering and memorizing something totally abstract now has a face and a name. brb changing major to education.
[deleted] · 2 points · Posted at 23:33:52 on January 9, 2016 · (Permalink)
Land surveyors, at least i Sweden and other metric countries, use gradians ("gon") where a full circle is 400 gon and a right angle 100 gon.
bjbarlowe · 2 points · Posted at 00:28:45 on January 10, 2016 · (Permalink)
Sure. The reason why it's divided into 360 is because the Sumerians (I think) had a base six math system and that's where it's derived from. That's also why there's 60 minutes in an hour.
[deleted] · 2 points · Posted at 00:50:09 on January 10, 2016 · (Permalink)
On another level this question makes us question the relationship between human symbols and the world they are supposed to represent. In the deepest sense aren't all symbols are essentially empty and it is only by custom that a symbol represents some "thing" in the object world.
astroteacher · 2 points · Posted at 01:00:16 on January 10, 2016 · (Permalink)
360 isn't arbitrary. There are 365 days in a year, so 1 degree is approximately the distance the sun moves along the ecliptic in one day. However, 360 is divisible by more numbers and is easier to divide by 4 in particular. The history of sexagesimal counting is very interesting https://en.wikipedia.org/wiki/Sexagesimal.
electrodude102 · 3 points · Posted at 01:18:39 on January 10, 2016 · (Permalink)
Seems pretty arbitrary to me. Is every fourth circle a leap circle?
Edit: well I guess that is the length of the four seasons, so I guess it's not all that arbitrary...
[deleted] · 2 points · Posted at 02:01:10 on January 10, 2016 · (Permalink)
There is no 'natural property' of a circle in relation to a quantity of 360. So it is arbitrary, although a little research (startpage.com it) will give you insight into the reasoning behind '360'. A circle does have a natural property which is not arbitrary, the ratio between its circumference and its 'width' (expressible as either its radius, or its diameter).
Luder714 · 2 points · Posted at 03:13:55 on January 10, 2016 · (Permalink)
As I can recall, using 360 allows for many multiples, since it is base 12, instead of base 10.
geking · 2 points · Posted at 03:45:58 on January 10, 2016 · (Permalink)
This is from the Babylonians. Same reason why we have 60 seconds per minute and 60 minutes per hour. They used a base 60 math system. (We use a base 10 and computers use base 2).
source/further reading
a1studmuffin · 2 points · Posted at 05:15:41 on January 10, 2016 · (Permalink)
Side note: Some game engines (eg. Allegro) divide a circle into 256 (28) degrees so an angle fits cleanly into 8 bits.
idemandtrialbycombat · 4 points · Posted at 16:04:48 on January 9, 2016 · (Permalink)
in ancient times, astronomers looked to the sky and saw that different stars moved each night. they noticed that it took 360 days to do one full rotation about the sky (give them a break, they had ancient tech and we're off by 5 days). for this reason, the stars moved in a "circle" by 360 units, or days. these units are now called degrees.
Belboz99 · 3 points · Posted at 16:15:22 on January 9, 2016 · (Permalink)
Gotta love the Babylonians... they gave us geometry, and the honeymoon (a moon's worth of honey-beer aka mead)
The_camperdave · 1 points · Posted at 16:15:09 on January 9, 2016 · (Permalink)
Ancient astronomers knew full well that it took 365 days for the stars to move through their circle. They were keen observers of the night sky, and they weren't stupid.
parad0xchild · 3 points · Posted at 17:38:58 on January 9, 2016 · (Permalink)
TIL that many people had awful math teachers who never explained how degrees relate to sine functions and radians relate to formulas.
No matter your good sounded explanation of it being arbitrary, it's not at all.
_AndrewC_ · 1 points · Posted at 21:35:29 on January 9, 2016 · (Permalink)
Er... in what way do you mean that degrees relate to sine functions? Surely any of the angle units in use can be used with sine etc?
nonameisgood · 4 points · Posted at 17:43:32 on January 9, 2016 · (Permalink)
ELI5 = can you answer my homework?
andreasbeer1981 · 5 points · Posted at 16:57:18 on January 9, 2016 · (Permalink)
It's named after the skateboard move, where the board goes a full circle during a jump, which is called a three-sixty. When the sumerans and babylonians discovered the circle, they remembered that awesome full circle skateboard trick and thus decided to use "three sixty" -> 3, 60 -> 3 hundred + 60 -> 360 degrees in a circle as an hommage to ancient skateboard skills.
If you don't believe me, look at these babylonian temple designs: http://lastdayscalendar.tripod.com/2f4a4430.gif - it's basically Tony Hawks dreams come true.
Picnic_Basket · 2 points · Posted at 03:28:57 on January 10, 2016 · (Permalink)
I like this answer.
MrXam · 4 points · Posted at 13:52:34 on January 9, 2016 · (Permalink)
So do y'all like the new layout of xvideos.com??
thirdeyegrind · 5 points · Posted at 14:59:58 on January 9, 2016 · (Permalink)
I don't mind it. I just want them to stop with the banners that let me know I can change it back.
[deleted] · 1 points · Posted at 23:26:15 on January 9, 2016 · (Permalink)
I don't like it. It seems like it use to load more videos per page, now I have to reload the pages more often.
Loki-L · 2 points · Posted at 08:00:44 on January 9, 2016 · (Permalink)
Yes, it is arbitrary. This is why there are alternate measurements of angles in use like for example radians (which involves pi) and even obscure decimal ones like gradians which subdivide a right angle into 100 parts instead of 90 as degrees do.
The 360° thing is still the most common one for most general cases and it goes back all the way to the same people who decided that the day should have 24 hours and stuff like.
Both degrees and hours by the way share the same subdivision; minutes and seconds. A degree is divided into 60 arc-minutes and those are divided into 60 arc-seconds each.
If you want you can always simply use something like 'turns' instead of a degree. 360° are one full turn. A right angle is a quater turn or 0.25 turns and a single degree is 1/360 of a turn or 0.00277.. turns.
If you want to divide the circle into 100 parts call them centiturns and use that.
It doesn't really change anything how you measure it.
Elios000 · 2 points · Posted at 13:43:28 on January 9, 2016 · (Permalink)
another option is to use radians
https://en.wikipedia.org/wiki/Radian
a full circle has 2pi radians
LeibnizIntegralKeks · 2 points · Posted at 15:34:48 on January 9, 2016 · (Permalink)
What are you even talking about? A circle is two pi radians.
The_camperdave · 0 points · Posted at 16:17:49 on January 9, 2016 · (Permalink)
Tau radians. A circle is divided into tau radians. Pi is illogical.
LeibnizIntegralKeks · 1 points · Posted at 16:24:55 on January 9, 2016 · (Permalink)
What does it matter? As long as its consistent its not any more or less efficient to use pi instead of tau.
mobott · 1 points · Posted at 16:59:17 on January 9, 2016 · (Permalink)
2 pi = 4 keypresses
tau = 3 keypresses
It's totally more efficient to use tau!
The_camperdave · 1 points · Posted at 17:05:50 on January 9, 2016 · (Permalink)
But it's not consistent. Pi is based on the diameter, so your base arc length should also be the diameter. With radians, the base arc length is the length of the radius, so the circle constant should also be based on the radius. Tau radians in a circle. Pi "dradians" in a circle. That's consistent.
LeibnizIntegralKeks · 1 points · Posted at 17:25:09 on January 9, 2016 · (Permalink)
You're right of course, I just prefer pi because I usually use it, there is no good reason to use pi over tau but I don't think it makes much of a difference.
_AndrewC_ · 1 points · Posted at 21:37:31 on January 9, 2016 · (Permalink)
That's a great argument that I'd never come across. Thanks.
When I borrow the Tardis, I shall travel history ensuring we all use base 12 and tau.
SamwiseTheOppressed · 2 points · Posted at 18:48:02 on January 9, 2016 · (Permalink)
There are 360 degrees in a full turn because it can be easily divided by 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360, which is quite useful. 100 can be divided by 2, 4, 5, 10, 20, 25, 50 and 100 which is less useful.
gladeye · 2 points · Posted at 19:47:45 on January 9, 2016 · (Permalink)
I'm in the midst of teaching my fourth grade students about angles and we discussed this exact question. I showed them that 100 degrees won't get you an accurate enough measurement, while 1,000 degrees would be near impossible to read. I always thought 360 was a nice compromise between the two, and is especially useful because 360 is such a highly divisible number.
Cletus_awreetus · 2 points · Posted at 00:22:31 on January 10, 2016 · (Permalink)
Of course.
You can divide anything by any number.
I think it's important to understand that.
matrixknight88 · 0 points · Posted at 00:50:07 on January 10, 2016 · (Permalink)
Except zero. But zero is technically not a number.
Cletus_awreetus · 1 points · Posted at 16:35:42 on January 10, 2016 · (Permalink)
Like black is technically not a color? :)
matrixknight88 · 1 points · Posted at 17:47:54 on January 10, 2016 · (Permalink)
Yeah.
[deleted] · 2 points · Posted at 17:07:15 on January 9, 2016 · (Permalink)*
[deleted]
kmoonster · 1 points · Posted at 19:15:18 on January 9, 2016 · (Permalink)
It is arbitrary in that it was the preferred system by a generation long gone, they chose it over other systems that could have been about as useful.
It was not selected out of a hat, but because it most closely reflected how they viewed the cosmos to be constructed, which in turn likely had something to do with their mythology and social constructs.
They could have used a different setup just as accurately. Measurements and demarcations are all arbitrary based on a society's needs, familiar things, and mythologies. The reasons they selected the current one with were not arbitrary. The set they chose, was.
fiwer · -1 points · Posted at 18:18:30 on January 9, 2016 · (Permalink)
"Vortex Math" is a bunch of nonsense, as is the rest of your post.
risot · 1 points · Posted at 22:50:30 on January 9, 2016 · (Permalink)
So i take it you don't actually understand it.
fiwer · 1 points · Posted at 02:44:10 on January 10, 2016 · (Permalink)
Yeah, just like all the people who call timecube nonsense. Clearly they just aren't capable of understanding 4 corner simultaneous days rotation of the Earth!
[deleted] · 1 points · Posted at 03:04:16 on January 10, 2016 · (Permalink)
You are educated stupid.
risot · 1 points · Posted at 03:29:19 on January 10, 2016 · (Permalink)
It's clearly something you haven't even attempted to understand which first of all shows how ignorant you are. Its relatively simple math and you have no idea it even exists because your too ignorant to spend 5 minutes learning about it. Why not try coming back when you've learned anything at all about it and then explain to me how it is wrong rather than talking about something thats entirely unrelated to try to make a "point" about something you know nothing about.
fiwer · 1 points · Posted at 03:33:23 on January 10, 2016 · (Permalink)
Have you attempted to understand that you are educated stupid and the Earth has 4 corner simultaneous days?
risot · 1 points · Posted at 03:50:41 on January 10, 2016 · (Permalink)
Clearly you will have to continue resorting to comparing this to unrelated things in order to call it "wrong" because A, you refuse to research it at all, and B, even if you did you still couldn't explain how its wrong. So bring on the next completely unrelated comment! You sound like an idiot.
fiwer · 1 points · Posted at 04:26:02 on January 10, 2016 · (Permalink)
Do you spend a lot of time researching things that are immediately and obviously complete nonsense? Do you legitimately believe that the ramblings of schizophrenics have value?
risot · 1 points · Posted at 06:00:51 on January 10, 2016 · (Permalink)*
By "immediately" you mean you didn't research this at all, and it is obvious because it doesn't even involve listening to a person, it is entirely math equations. But of course you wouldn't know that because your too dumb to research anything about it.
Its amazing how forcefully you are refusing to research it at all whatsoever because your afraid i might be right. You can't even say a single word about it. If you want to try debating it thats fine but until your actually capable of discussing the first thing about it, shut the fuck up.
fiwer · 1 points · Posted at 15:12:13 on January 10, 2016 · (Permalink)
I did research it, it's complete nonsense. When you have a degree in a math heavy field like I do, you get exposed to a ton of cranks who believe they've unlocked some magical secret to the universe and learn to recognize them pretty quickly.
risot · 1 points · Posted at 18:18:18 on January 10, 2016 · (Permalink)
Yet for some reason you are incapable of explaining how its wrong. Again, you cannot even say a single word about it.
fiwer · 1 points · Posted at 18:35:42 on January 10, 2016 · (Permalink)
There's nothing to even explain. Again for comparison with Timecube, if I ask you to prove that the Earth doesn't have 4 simultaneous corner days within a single rotation, what can you say to that? There's no way to disprove lunatic ramblings because they aren't based in reality or logic.
You're either a very uneducated conspiracy nut with no math background or a legitimately crazy person if you believe in Vortex Math so it's unlikely any amount of evidence will convince you otherwise, but here's a link debunking it anyway. http://goodmath.scientopia.org/2012/06/03/numeric-pareidolia-and-vortex-math/
risot · 1 points · Posted at 20:16:55 on January 10, 2016 · (Permalink)
Interesting how that debunks everything except the one claim that i actually made, in fact it admits that doubling or dividing any single digit number will result in a never-ending, repeating pattern. The only claim that i made is that these patterns exist for the same reason that there is a never-ending, repeating pattern that comes out of doubling or dividing 360, both of these patterns work in the same exact way. This much is undeniable, even from this debunkers perspective.
On another note, when Einstien was asked what its like to be a genius, he responded "i wouldn't know, ask Tesla". Are you claiming that Tesla's use of 3, 6, and 9 was all just bs even though some of his inventions are still classified? I'm pretty sure im going to trust what two of the greatest minds to ever exist have said over a random redditor lol
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Jaywebbs90 · 1 points · Posted at 13:00:53 on January 9, 2016 · (Permalink)
All measurement systems are arbitrary. At a certain point it just becomes which makes more sense to use or which is easier. Iirc 360 degree model harkens back to Ancient Babylon who used base 60. And was modeled because of our year being 365 days.
gonzo41 · 1 points · Posted at 13:28:25 on January 9, 2016 · (Permalink)
if you divide a circle by 6400, 1 degree is roughly 1 meter at 1000 meters. Its handy if you need to shoot someone...
Circle stuff.. i thought the 360 was from being able to divide a circle into triangles with effectively flat sides that would make measuring the diameter possible.
important - drunk.
My_usrname_of_choice · 1 points · Posted at 18:33:06 on January 9, 2016 · (Permalink)
Mils= miliradians
I'm doing a service to point this out every time I see it in this thread. I only just learned this.
WarDredge · 1 points · Posted at 13:56:13 on January 9, 2016 · (Permalink)
A little late to the party but i've seen some answers that were close, this is the full picture;
Roughly 4500 years ago, the Babylonian time calendar was based upon a civilization wide understanding of base-60. Everything involving the time-table we adapted from them, Using 6 for Babylonians is like the difference between 10 and 1 for us, It isn't hard to factor up to 360 by their standards.
This all came from early predictions of a 'year' or then 'cycle', by tracking the sun and movement of the stars as well as seasonal occurrences, it took 90 days for each 'season' to change.
From this principle as we later adapted in our own modern culture now a primitive circle (read: Cycle) was mathematically defined as 360, because of the divisions it allowed and a little bit of heritage to the first ever humans to define a circle (inadvertently).
kyubez · 1 points · Posted at 13:57:26 on January 9, 2016 · (Permalink)
someone please answer this, if it is arbitrary, why 360? why not 100? i get that 360 has more factors, but wouldnt 100 have been more convenient considering how we use the metric system?
GoingToSimbabwe · 1 points · Posted at 14:16:54 on January 9, 2016 · (Permalink)
You asked the exact question OP used.. Scroll around and you will find answers.
OFF_THE_DEEP_END · 1 points · Posted at 19:14:49 on January 9, 2016 · (Permalink)
100 would be more familiar. But not more convenient.
StonehengeMan · 1 points · Posted at 14:00:42 on January 9, 2016 · (Permalink)
Western militaries divide their circles into 6400 mils (as they are known) and the Russians use 6000 mils.
One degree is about 17.3 mils.
My_usrname_of_choice · 1 points · Posted at 18:35:21 on January 9, 2016 · (Permalink)
Mils= miliradians
I'm doing a service to point this out every time I see it in this thread. I only just learned this.
[deleted] · 1 points · Posted at 14:05:05 on January 9, 2016 · (Permalink)
The ancient's calculated the length of 1 year as 360 days (close to the actual value of 365.25) that's why its 360 degrees.
Tsorovar · 1 points · Posted at 14:21:38 on January 9, 2016 · (Permalink)
There's no such thing as a unit of measurement that isn't arbitrary. It's usually a matter of convention and familiarity which ones we use, though sometimes ones that have more practicality gain ascendancy.
umbama · 1 points · Posted at 14:22:08 on January 9, 2016 · (Permalink)
You can geometrically construct the 360 subdivisions using the equivalent of a compass and pencil - string and stick in sand for example. It's very easy. That would be a consideration.
ask-a-local · 1 points · Posted at 14:30:23 on January 9, 2016 · (Permalink)
To be honest, the only reason we still use 360 degrees is because it divides cleanly by 2, 3, 4, 5, 6, 8, 9, 10, and 12. Which makes it easy to teach basic geometry.
Historically the usage is tied to marine navigation. But that is more interesting and complicated.
dorondoron · 1 points · Posted at 14:34:48 on January 9, 2016 · (Permalink)
yes it's arbitrary, the radian is unitless, if you wanted to make your own measurement system for angles, you could. That being said, 360 is a nice number to work with.
Fatburg · 1 points · Posted at 15:06:11 on January 9, 2016 · (Permalink)
You can divide a circle by any arbitrary method you want. For example:
Mils
tiggerbiggo · 1 points · Posted at 15:29:35 on January 9, 2016 · (Permalink)
There is another measurement of angles called "Gradians", and it does exactly that. 360o = 400g , so it is easier to use with base 10.
SelfProclaimedBadAss · 1 points · Posted at 15:30:54 on January 9, 2016 · (Permalink)
I always figured that our Time, (seconds, minutes, hours), Day length, and radius principles, always fitting neatly into a base 12 design had something to do with us ending up with it...
miraoister · 1 points · Posted at 15:34:52 on January 9, 2016 · (Permalink)
What is the history of 360 degrees?
Wee2mo · 1 points · Posted at 15:59:58 on January 9, 2016 · (Permalink)
360 was popular because it has a lot of counting numbers that can divide it into counting numbers.
[deleted] · 1 points · Posted at 16:28:42 on January 9, 2016 · (Permalink)
Everything is arbitrary. Even the integers that we think of as ubiquitous and certain are completely meaningless realistically, and have virtually 0 probability of existing in any true capacity.
360 degrees is a convenient choice for a number of reasons. First, the number 360 is divisible by a bunch of small integers: 2,3,4,5,6,8,9,10, and even 12 (like a clock). This is good because you can have even quadrants or thirds or sixths or eighths (like NW, SW, SE, etc) if you like. Our minds sort of stop really easily visualizing prime parts around 7 and onward-you can draw a square pretty easily but try drawing a heptagon! Second, 360 divisions is fine enough to allow for decent accuracy without too much mathematics. If you start in one place and head 10 miles in one degree direction, and you were off by maybe a half a degree, you are still at most only a few hundred feet from your desired destination.
Casteway · 1 points · Posted at 16:33:22 on January 9, 2016 · (Permalink)
Of course it's arbitrary. Any number system or system of measurements or standards is arbitrary. It's the same way you can use either kilograms or pounds to measure weight. The standard can be whatever you want it to be as long as a group of of people agree on it. I believe the 360 degrees in a circle is based loosely on the 365 days in a year somehow? http://math.stackexchange.com/questions/340467/why-is-a-full-circle-360-degrees
houstonsabers · 1 points · Posted at 16:34:40 on January 9, 2016 · (Permalink)
A circle can be divided into any number of lines you can fit. It can be a thousand, a million, or more.
killingit12 · 1 points · Posted at 16:52:37 on January 9, 2016 · (Permalink)
Yeah completely arbitary. Degrees are also made up of "arcminutes" and "arcseconds". There is 60 arcminutes in one degree, and 60 arc seconds in one arcminute, or:
1 revolution = 360° = 21,600' = 1,296,000''
1° = 60'
1' = 60''
Thats also where the unit 'parsec' came from, where a parsec is the distance from the earth when 1 AU subtends an angle of one arcsecond.
Measure76 · 1 points · Posted at 17:07:44 on January 9, 2016 · (Permalink)
Ok, so it is theoretically possible, but it seems like it would be a lot harder to do say, 3 digit by 3 digit multiplication by hand.
Xaxxon · 1 points · Posted at 18:02:17 on January 9, 2016 · (Permalink)
That's like saying "Is a mile arbitrary? Could we divide it up into kilometers?"
landrer · 1 points · Posted at 18:03:18 on January 9, 2016 · (Permalink)
How does base 12 fit into this, or that just a coincidence?
RLBaRbArIaN · 1 points · Posted at 18:03:39 on January 9, 2016 · (Permalink)
Make a metric type system, 100 new degrees in a circle, 10 new hours of 100 minutes of 100 seconds in a day, etc. Hard to get it to be popular tho.
[deleted] · 1 points · Posted at 18:24:45 on January 9, 2016 · (Permalink)
I'd love to switch to a metric time system but no one else would :(
Anders_A · 1 points · Posted at 18:20:01 on January 9, 2016 · (Permalink)
Yes it is completely arbitrary. Other commonly used divisions are 2*pi and 400.
400 was used in navigation back when the definition of a kilometer was a 1/40000th of earths circumference. The distance from the pole to the equator was defined as 10000 km.
2*pi is the choice used when doing math, since it's much simpler to use when we're looking for exact solutions and not estimations.
pixelypunto · 1 points · Posted at 18:34:36 on January 9, 2016 · (Permalink)
It's arbitrary, probably due to the astronomist that they divide the circle in more or less parts that has a year, a year has 365 days and a circle 360 parts..
michaelthe · 1 points · Posted at 18:36:13 on January 9, 2016 · (Permalink)
It isn't completely arbitrary as some have said. 360 is a Highly Composite Number. While there is some arbitrary factor, there is a very specific reason why that number was 360 and not 359 or 361. You can see some other useful numbers on that list, such as 12 (inches in a foot), 24 (hours in a day), 60 (seconds, minutes).
ChaozCoder · 1 points · Posted at 18:44:22 on January 9, 2016 · (Permalink)
Afaik it goes back to babylonian astrology, they divided the year into 360 days, 5 days of the year they just ignored. 360 is very divisible. and it is 6x60, the babylonians had a 60 based number system.
polot38 · 1 points · Posted at 18:58:09 on January 9, 2016 · (Permalink)*
Basically, yes. 360 degrees is arbitrary. It might have some historical significance or something, but that is, in mathematical terms, arbitrary. It has a lot of factors, but that is also arbitrary as there are a lot of numbers with a lot of factors. The other main system of radians, however, is a little less arbitrary, although that mostly has to do with differentiating trig functions.
SanguinaryArcher · 1 points · Posted at 18:59:21 on January 9, 2016 · (Permalink)
Seeing all these comments that say it is completely arbitrary, and only a few mention Pi at all. After calculating the value of Pi, that calculation can be used to create a perfect circle (by mashing it into an equation and shit, proofs, technical terms, blah blah). Anyways, I assume that since a perfect circle can be created by using the value of Pi, 360 was also somehow derived from that.
But as you can see, I am very far from sure about this, so don't quote me.
jrm2007 · 1 points · Posted at 21:40:03 on January 9, 2016 · (Permalink)*
It is interesting to note that after the French Revolution where many changes were attempted they tried for decimal time (100 seconds per minute and 100 minutes per hour, 10 hour days I think) and it would not surprise me if they considered your idea also.
BobSagetOoosh · 1 points · Posted at 22:27:37 on January 9, 2016 · (Permalink)
As a previous commenter said, 360 works with pi. Trigonometry frequently uses pi (a set value at 3.14159265... that cannot change) along with angle values to work out other angles, sides, areas, circumferences, radii, diameters etc. If the 360 degrees was changed, the proportion of each angle would not, but its value would, and so the algebra would no longer work correctly. Pi could be changed accordingly, however if this happened it would no longer be usable without angles, e.g. pi x (radius squared) = area of a circle would be incorrect.
shafthurtsalot · 1 points · Posted at 22:27:58 on January 9, 2016 · (Permalink)
360 was also chosen because it is very close to the number of days in a year. (The earth moves about 1 degree around the sun per day) So it's a mix of that and being able to divide it evenly by many number
RabidRabb1t · 1 points · Posted at 22:38:17 on January 9, 2016 · (Permalink)
It's like using feet or meters to measure distance. Alternatives to degrees include radians (of which there are 2*pi in a circle). The underlying angle is independent of how it's represented
[deleted] · 1 points · Posted at 22:39:14 on January 9, 2016 · (Permalink)
Arbitrary? Yes, as all conventions are. In science rads are used (1 turn = 2Pi = 6.28..) since it has really neat mathematical properties that makes you say "it just works".
360 was chosen because it divides by a lot of useful numbers (2, 3, 4, 5, 6, 9, 10, 12, 15, 20 and so forth).
Also, the Babylonians divided an hour in 60 minutes made of 60 seconds. Also there it's close to the number of days there is in a year, so that for a given hour in the day, everything shifts about 1 degree in the sky.
ChipAyten · 1 points · Posted at 23:04:46 on January 9, 2016 · (Permalink)
The military, most commonly artillery divisions use miliradian which is a circle divided by 6283 (6400 usually). It's for more accurate targeting over large distances. 1 degree is a bad miss, one that often kills friendlies over a few miles.
[deleted] · 1 points · Posted at 23:39:23 on January 9, 2016 · (Permalink)*
It's not arbitrary. People a long ass time ago figured out that time can be measured very easily using the numbers 0,1,2,3,4,5, and 6. Time is determined by the rotation of the earth, and the earth is round therefor time is measured using a circle. There are close to 360 days in a year, so they just used that instead and tried to figure out a way to explain the other 6.25 days. Notice how there are 60 seconds in a minute and 60 minutes in an hour. That wasn't an accident. The math just seemed to work out. People keep saying that ancient civilizations thought the year was 360 days long, and I am pretty sure that isn't right. I don't think people thought the year was 360 days. I think 360 made the math workout easier, so they removed 6.25 days from the calendar year and made up a reason to omit them. Many ancient civilizations were pretty clever and could make impressive calculations, so I can't fathom them not being able to count the days using orbital patterns and then do a simple calculation to determine the number of days in a year.
Also, I might not be 100% right about this, but I seem to remember some archeoastronomy theorizing that if you hold your arm out your arm towards the sky at night and use your thumb as a reference point, that there are typically 360 thumb width distances when measuring the year looking at the constellations. Somebody who knows more, please chime in here, I can't remember who it was that said that.
Also, you could measure a circle using 100 degrees, but you are going to fuck up our entire math system to where people had to use decimal numbers or fractions to do what we consider basic calculations.
Sort of on topic: Can someone explain to me if we correct the calendar every 128 years to make up for the fact that the year is not 365.25. It is 365.24219 days long. That means we lose a day every 128 years. I never have seen this brought up?
UraMallas · 3 points · Posted at 00:11:53 on January 10, 2016 · (Permalink)
To your last point, the last year of every century (1900) is not a leap year. This applies to centuries that are not multiples of 400 (2000) which are leap years unless they are also multiples of 4000 (4000).
[deleted] · 1 points · Posted at 00:14:54 on January 10, 2016 · (Permalink)
Oh cool. When did they start doing that? It had to have been pretty recent, last 1000 years.
UraMallas · 5 points · Posted at 00:19:07 on January 10, 2016 · (Permalink)
Pope Gregory in March 1582. By that time, the calendar year was 10 days off the seasonal year. ( The real concern was not Christmas, but Easter, which had to occur near the vernal equinox and according to the lunar cycle, but that's another story.) They made two corrections. The first was that they just dropped ten days. The day after October 5, 1582 became October 15, 1582. (Some countries adopted this change later, in some cases centuries later.) This restored the equinox to its rightful place. The second change was to reform the calendar to prevent slippage in the future; and we use that same calendar system today, called the Gregorian.
[deleted] · 4 points · Posted at 00:23:04 on January 10, 2016 · (Permalink)
Thanks man, very interesting.
AttalusPius · 1 points · Posted at 23:55:55 on January 9, 2016 · (Permalink)
Dammit... I'm annoyed that everyone else here already explained this. basically 360 is an amazing number and you can divide it by A LOT of different numbers
gunfulker · 1 points · Posted at 00:20:18 on January 10, 2016 · (Permalink)
If I'm not misinformed, pretty sure it dates back to base 12 being used for time. Minutes, hours, half days, inches, degrees, etc all come from an ancient culture that counted things by the 12s or 16 or 60 or something like that. Hopefully someone who knows it off the top of their head can elaborate.
Attila226 · 1 points · Posted at 00:28:11 on January 10, 2016 · (Permalink)
I heard they chose 360 because people used to think there w ere 360 days in a year. To answer your question, the number of degrees is entirely arbitrary.
frubjoppa234 · 1 points · Posted at 01:35:18 on January 10, 2016 · (Permalink)
They chose 360 because that's how many unique combinations of letters there are in the word circle. Not really why, 360 is just convenient for math.
ilmman · 1 points · Posted at 01:51:56 on January 10, 2016 · (Permalink)
Isn't the circle shape amazing? It's like the most interesting shape every. It's universal and the ratio is always going to be the same. In most technology we use circular motion for things like dysons vaccums and all. I think the secret to the universe lies in the power of the circle.
getoffmylawnplease · 1 points · Posted at 04:26:07 on January 10, 2016 · (Permalink)
No. The top GIF making it sound simple is wrong. A completely random number can't be divided evenly and rationally
RICH_PENZOIL · 1 points · Posted at 05:48:56 on January 10, 2016 · (Permalink)
Never heard of a pie chart? a circle is 360* for the same reason a square is, and the same reason a line is 180*
akuthia · 1 points · Posted at 10:48:59 on January 10, 2016 · (Permalink)
Oh i understand that but there was one degree from a for profit and 10 years between high school algebra and the calc 1 class
[deleted] · 2 points · Posted at 09:36:27 on January 9, 2016 · (Permalink)
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NefariousCat · 1 points · Posted at 11:37:48 on January 9, 2016 · (Permalink)
That could be coincidence, meaning 360 is still arbitrary.... Honestly this seems like a question for AskHistorians.
DKlurifax · 1 points · Posted at 11:01:54 on January 9, 2016 · (Permalink)
In the Danish military some units use nygrader (new degrees) which is 400 degrees to a circle. Was told by my friend who was a platoon leader in a mortar division.
lucaslower · 2 points · Posted at 14:13:46 on January 9, 2016 · (Permalink)
I think that would be gradians, because that divides a right angle into 100 degrees, so a full circle would be 400.
[deleted] · 1 points · Posted at 13:30:59 on January 9, 2016 · (Permalink)
It is just an arbitrary human convention. 360 is there for convinience (because of its divisors, 2, 3, 4, 5, 6, 8, 9, 10 etc.).
washbaerli · 1 points · Posted at 13:37:44 on January 9, 2016 · (Permalink)
I actually just taught this to my 10th graders the other day! Circles have 360° because the ancient mathematicians (I forgot who exactly) noticed that the stars & constellations would move ever so slightly every night, and after 1 year they would be back where they started. So even though it would be a little over 364 days, 360 is a better divisor.
Mrknowitall666 · 1 points · Posted at 16:20:20 on January 9, 2016 · (Permalink)
So, math win; history fail.
thedankbank1021 · 1 points · Posted at 17:01:01 on January 9, 2016 · (Permalink)
Yes it's totally arbitrary, and we also use another form of measuring circles. Radians. Radians are technically more accurate, and their system has a good reason for using the measurements it does, but degrees work well enough for any practical application. And degrees are a lot easier for most people to understand. After all, to use radians you have to have some understanding of trig, and algebra. For degrees you don't need any of that.
tokodan · 2 points · Posted at 17:19:55 on January 9, 2016 · (Permalink)
I don't understand what you mean with the accuracy of the angular units. As far as I know, 360 degree is EXACTLY a whole circle, as is 2 pi.
[deleted] · 2 points · Posted at 18:18:04 on January 9, 2016 · (Permalink)
You're exactly right, they're both easily converted to each other. This is like saying Celsius is better than kelvins, makes no sense they're the same measure just a different nominal value
kmoonster · 1 points · Posted at 19:19:09 on January 9, 2016 · (Permalink)
Breaking down a degree into "1.5 degrees" or "2.7" is somewhat more difficult because they are not designed on base-10 and you have to convert base-10 into degrees which are base-60.
This is why your GPS does not offer you one neat 'location' option, but rather offers you at least three. You can have DDMMSS, or DD.XXX, or one of a few other formats, most of which are approximations (very accurate approximations, but approximations none the less).
tokodan · 1 points · Posted at 22:57:12 on January 9, 2016 · (Permalink)
But if longitude and latitude lines were defined in radians (and GPS devices therefore used radians), they would display a fraction of pi, which converted to decimal would give an approximation (I mean if you have 7/22 pi North, that would be interpreted as 0.31818N).
Come to think of it, degrees are probably more useful for digital devices as well, since it's probably (don't quote me on this, it's a guess) easier to convert base-10 to binary.
kmoonster · 1 points · Posted at 03:32:00 on January 10, 2016 · (Permalink)
You can buy magnetic compasses that read out in radians :). This suggests there are maps that do, but I am not familiar with them.
classyinthecorners · 1 points · Posted at 19:34:41 on January 9, 2016 · (Permalink)
I believe the 360 degrees had something to do with the early approximations for the number of days in a year... 365 days is what we know now, but 360 degrees isn't that far off
[deleted] · 1 points · Posted at 21:58:24 on January 9, 2016 · (Permalink)
No, 360 degrees is not arbitrary. Yes, you can use other divisions. 360 degrees is harmonic with Pi.
kender00 · 1 points · Posted at 23:09:10 on January 9, 2016 · (Permalink)
That's the exact sort of talk that a supporter of the Metric system would say.
Long live Imperial units!
sidescrollin · 1 points · Posted at 01:51:50 on January 10, 2016 · (Permalink)*
" In 1936, a tablet was excavated some 200 miles from Babylon. The mentioned tablet, whose translation was partially published only in 1950, is devoted to various geometrical figures, and states that the ratio of the perimeter of a regular hexagon to the circumference of the circumscribed circle equals a number which in modern notation is given by 57/60 + 36/(602) (the Babylonians used the sexagesimal system, i.e., their base was 60 rather than 10).
The Babylonians knew, of course, that the perimeter of a hexagon is exactly equal to six times the radius of the circumscribed circle, in fact that was evidently the reason why they chose to divide the circle into 360 degrees."
Why is it still used commonly? I really don't know. If you get into any math above algebra everything is just in radians because it isn't totally arbitrary like degrees and is extremely useful. Next time you here someone call out the US on using inches, ask them whether they measure angles in degrees or radians and proceed to hack away at their double standards.
geppetto123 · 1 points · Posted at 02:09:17 on January 10, 2016 · (Permalink)
No the selection of 360 is not arbitrary like mentioned by most comments here but very wisley chosen by the Mayas in the same way like the numbers 24, 12 and 60 on the clock.
360 is the smallest number with 24integer divisiors which end up without decimals. For example the much larger number 1000 has only 12 integer divisiors which makes it unpractial. However using 720 instead of 360 would have had even more divisiors but was likely thought to be to large for most angles used.
Using newdegree where a full circle is 400newdegree sounds great in the beginning until u have to deal with decimals where with degree everything was smooth.
Edit: These numbers have a special name, but I don't remember and didn't find it on mobile inet.
purified_water · 1 points · Posted at 02:22:24 on January 10, 2016 · (Permalink)
Literally every single number is arbitrary...
Any number could be any other value if we just happened to define a different system to use them in.
app4that · -4 points · Posted at 10:58:43 on January 9, 2016 · (Permalink)
Not arbitrary: think # of days in a year, now realize that number isn't perfect for dividing into lots of other numbers, so have your high priests/mathematicians (same difference) come up with some excuse why the Sun/God/thing took a rest for 5 days and you get 360. Egyptians did this and probably learned from the Babylonians and Sumerians Anyway, 360 is nicely Divisible by 1,2,3,4,5,6,.... Yeah, they liked that number a lot. Circles were sacred (Sun, moon, orbits -Stonehenge type structures, yeah, ellipses came later) and so 360 had to be perfect.
[deleted] · -1 points · Posted at 10:03:25 on January 9, 2016 · (Permalink)
way back when, some ancient skygazer noticed "hey, that shadow is the same size and shape that it was about 360 (~1 year) ago," and showed the amazing phenomenon to his friends. over time, it came to be established that the year consisted of four seasons of about 90 days each.
science advanced and it was hypothesised that the seasons were the result of the sun orbiting the earth, so 360 degrees was a convenient analogue.
math and astronomy became more sophisticated, and eventually it was discovered that a year is actually 365 days. So those extra days became "holy" days (holidays).
RUST_LIFE · 2 points · Posted at 10:47:33 on January 9, 2016 · (Permalink)
Thankfully we now know that the earth orbits the sun a lot more than the sun orbits the earth
[deleted] · 1 points · Posted at 23:27:56 on January 9, 2016 · (Permalink)
365.25
[deleted] · 1 points · Posted at 01:55:48 on January 10, 2016 · (Permalink)
365.242, if you're gonna take it pedantic.
ibenchpressakeyboard · 0 points · Posted at 11:37:26 on January 9, 2016 · (Permalink)
You mean like a pie chart based on percentages...?
KubrickIsMyCopilot · 0 points · Posted at 14:52:15 on January 9, 2016 · (Permalink)
It is arbitrary. The Greeks chose 1/360 as the unit angle because they liked how easy it is to divide 360 into many other numbers.
[deleted] · 0 points · Posted at 15:07:44 on January 9, 2016 · (Permalink)
Yep, its also actually a pretty good number. You can have a third, quarter and fifth as a hole number. A oppose to 100.
ericvanwinkle · 0 points · Posted at 15:11:12 on January 9, 2016 · (Permalink)
This is the reason I studied liberal arts in college. None of my high school math teachers could tell me why there are 360 degrees. (I would have been just as happy if they had told me we would work in radians as we progressed.) As it happens, I learned as part of a tangential discussion in a philosophy class that the 360 degree circle comes from the solar calendar. (Tangential! I love it when a pun comes together!)
LeibnizIntegralKeks · 2 points · Posted at 15:40:35 on January 9, 2016 · (Permalink)
Your high school maths teachers must have been awful, but couldn't you just have accepted that it's an arbitrary measurement? There are historical reasons for most arbitrary measurements like that, for example the mile is a thousand double steps and the cubit is the length between the elbow and the tip of the middle finger, it was simply convenient to do it that way.
pjokinen · 0 points · Posted at 15:27:08 on January 9, 2016 · (Permalink)
It is completely arbitrary, just like how it's arbitrary that there are 60 minutes in an hour.
IIRC it is because the Assyrians pioneered early geometry and they thought that 360 was a "perfect" number because it was divisible by so many different things.
SamwiseTheOppressed · 0 points · Posted at 18:48:01 on January 9, 2016 · (Permalink)
There are 360 degrees in a full turn because it can be easily divided by 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180 and 360, which is quite useful. 100 can be divided by 2, 4, 5, 10, 20, 25, 50 and 100 which is less useful.
Anrza · 0 points · Posted at 18:49:29 on January 9, 2016 · (Permalink)
It seems like everyone saying it's arbitrary, but is it really? I thought it was a rest of the Babylonian system which, in turn, was because they thought the year was 360 days long?
creek_slam_sit · 0 points · Posted at 19:00:50 on January 9, 2016 · (Permalink)
I have an assumption that I've not really researched... so we have a base 10 system for counting because in the early development of civilization ND language they would have used the simplest observations to construct the most complex ideas. So the fact that we have ten fingers basically lead to our base ten system.
In a similar way early thinkers needed to generate observational accuracy so that they could convey information to other people in writings and descriptions. On of the most complex observational muses would have been the night sky. This apparent sphere like dome offered patterns that could be observed, but how could these patterns be explored and how could this exportation be communicated to others. Well the main governing pattern to this night show is of course the year..... and finally my conclusion, the year is damn near 360 days thus it would make sense to split the sphere that makes up the heaven into 360 seperate sections. Why not 365? Well early observers may not have been as keen on observation as we are today so an estimation would have sufficed. And as a caveat 360 had a great deal of factors which lends itself well to mathematical manipulation (as others have mentioned in the thread)
WriteDude · 0 points · Posted at 21:34:47 on January 9, 2016 · (Permalink)
A circle is 360 degrees because the ancient Greeks (iirc) thought a year was 360 days. In other words, it's a completely arbitrary number which survives simply because it would be too troublesome to change (and there's no particular reason to change it).
chad303 · 0 points · Posted at 02:02:21 on January 10, 2016 · (Permalink)
Arbitrary, yes, and very old. I believe the ancient Babylonians modeled the circumference of a circle with an inscribed hexagon. This gives Pi = 3 which is a pretty good estimate for bronze age math. This value for Pi actually shows up in the Bible. If you connect all the points where the inscribed hexagon intersects the circle, you get 6 triangles. The base number for the Babylonian number system is 60, and so, if you assign 60 degrees to every triangle, you get 360 degrees in a circle.
geppetto123 · 0 points · Posted at 02:08:16 on January 10, 2016 · (Permalink)
No the selection of 360 is not arbitrary like mentioned by most comments here but very wisley chosen by the Mayas in the same way like the numbers 24, 12 and 60 on the clock.
360 is the smallest number with 24integer divisiors which end up without decimals. For example the much larger number 1000 has only 12 integer divisiors which makes it unpractial. However using 720 instead of 360 would have had even more divisiors but was likely thought to be to large for most angles used.
Using newdegree where a full circle is 400newdegree sounds great in the beginning until u have to deal with decimals where with degree everything was smooth.
Edit: These numbers have a special name, but I don't remember and didn't find it on mobile inet.
geppetto123 · 0 points · Posted at 02:08:47 on January 10, 2016 · (Permalink)
No the selection of 360 is not arbitrary like mentioned by most comments here but very wisley chosen by the Mayas in the same way like the numbers 24, 12 and 60 on the clock.
360 is the smallest number with 24integer divisiors which end up without decimals. For example the much larger number 1000 has only 12 integer divisiors which makes it unpractial. However using 720 instead of 360 would have had even more divisiors but was likely thought to be to large for most angles used.
Using newdegree where a full circle is 400newdegree sounds great in the beginning until u have to deal with decimals where with degree everything was smooth.
Edit: These numbers have a special name, but I don't remember and didn't find it on mobile inet.
[deleted] · -3 points · Posted at 19:08:39 on January 9, 2016 · (Permalink)
[deleted]
Zakatikus · 7 points · Posted at 19:45:24 on January 9, 2016 · (Permalink)
It's amazing you didn't address OP's question at all
SideShow222 · 3 points · Posted at 19:58:11 on January 9, 2016 · (Permalink)
Let me ELI5 for you: "Yes, I'm a land surveyor...."
Zakatikus · 1 points · Posted at 22:15:03 on January 9, 2016 · (Permalink)
"is there a reason it's 360 instead of any other number?" response: "degrees minutes and seconds yo!"
His job merely adopts the number that OP questions. Please explain the importance of 1,296,000 parts of a circle? Is this a magic number? Does this answer OP's question? I literally have no clue where Mr. Land Surveyor was going with this.
Let me ELI5: Unless he's going to connect some sort of dot between what he does and WHY it is that way then it doesn't address OP's question at all.
unequivocali · -3 points · Posted at 20:24:38 on January 9, 2016 · (Permalink)
360 degrees is intertwined with our initial basic conception of a calendar year. 12 months each 30 days. Each day is one degree around the sun.
Also: we can divide 360 by 100... It's 3.6!
jonnyp11 · 4 points · Posted at 20:37:02 on January 9, 2016 · (Permalink)
No. Just...no. The fact that a year is close to 360 days is a coincidence, no other planet has the same number of days per year, or length of day, or anything else really.
unequivocali · 1 points · Posted at 17:25:29 on January 10, 2016 · (Permalink)
Yes the planet we live on and a numbering system created by us
It's completely arbitrary. But that doesn't mean they aren't linked - which they are
unequivocali · 1 points · Posted at 17:29:16 on January 10, 2016 · (Permalink)
Also this... http://usatoday30.usatoday.com/news/science/wonderquest/2002-06-21-circle.htm
DukeSausageToss · 1 points · Posted at 01:35:52 on January 10, 2016 · (Permalink)
The point of measurement is to get as many whole numbers as possible, dividing 360 by 100 and getting 3.6 is impractical
knowledge-is-freedom · -4 points · Posted at 12:44:34 on January 9, 2016 · (Permalink)
Mathematics is entirely arbitrary, just like any other conceptual thought. You could choose to create a system of mathematics and measures that is unlike our mathematics, is self-consistent, and cannot be integrated into normal maths and measures.
eyecikjou567 · 2 points · Posted at 12:56:18 on January 9, 2016 · (Permalink)
Prime Numbers are pretty consistent over all mathematical systems if you ask me.
It even works if you don't have division, you can figure out primes with subtraction too.
[deleted] · 1 points · Posted at 15:10:37 on January 9, 2016 · (Permalink)
[deleted]
knowledge-is-freedom · 0 points · Posted at 16:59:18 on January 9, 2016 · (Permalink)
Uhh huh.
Just because my point went completely over your head doesn't mean I'm not up to date in math.
onesonesones · -1 points · Posted at 13:51:38 on January 9, 2016 · (Permalink)
Our numbering system is likely base 10 because of fingers, no?
Likewise they probably went with 360 for degrees based on the divisibility factor. I dont believe it's because a year is approx 360 days. If anything, less of a factor.
eqleriq · -4 points · Posted at 17:10:56 on January 9, 2016 · (Permalink)
a circle divided by 100 is 3.6°
to all those saying it is arbitrary: it is not. it has ties to early astronomical estimates
My_usrname_of_choice · 1 points · Posted at 18:34:25 on January 9, 2016 · (Permalink)
Wow you're retarded. How is a degree defined?
eqleriq · 1 points · Posted at 19:51:10 on January 11, 2016 · (Permalink)
By 1/360th of a circle: that's pretty fucking obvious. Next question.
There are other definitions, too, involving radians and pi.
But yes, I'm the retarded one. What are radians and pi "based on?"
My_usrname_of_choice · 1 points · Posted at 20:38:44 on January 11, 2016 · (Permalink)
Pi is the ratio between the radius and diameter of a circle. Is isn't arbitrary, it's the same for every single circle.
1/360th is entirely arbitrary.
Glad we agree.
eqleriq · 1 points · Posted at 17:25:36 on January 12, 2016 · (Permalink)*
Guess what else is the same for every single circle: they're 360 degrees.
It's based on a rough estimate of the number of days it takes the earth to circle the sun, which was accepted as usable due to it being the lowest number with the most whole number multiple pairs. This was considered divine serendipity, but I guess you lack basic geometric historical knowledge.
Rough estimates and the will of the gods != Arbitrary
I answered the question in the original post:
Is it arbitrary? No.
Could we divide a circle by 100? yes, 3.6°.
What is 3.6°? 1/100th of a circle.
What is 360°, 1 circle.
It's like asking if the word "troll" is arbitrary. Then you point out some sort of historic definition of it, but in the end some asshole trolled someone else and out came the meat scraping sound "troll." Perhaps tens of thousands of years ago that sound was "ehfhhggg" but there you go. Is it arbitrary? No, because in 1300 ancient germany someone fell on a banana peel and landed under a bridge, and shouted "trulle." He broke his back, couldn't move and was now the "trulle" under the bridge.
Circles are, by definition, 360°.
Feel free to change it to 273.321136° based on the number of days a year your feelings aren't hurt on the internet
Rhynchelma · 1 points · Posted at 17:38:55 on January 12, 2016 · (Permalink)
Rule 1, please. We know the Internet can be a rough place, but ELI5 has rules.
BTW, quick bit of editing of the last sentence there...
[deleted] · -1 points · Posted at 11:15:26 on January 9, 2016 · (Permalink)
Graphic artists learn that there are many ways to divide a given measure into equal parts. For example, rather than using inches, quarters, eights and sixteenths, etc. it is easier to divide the line using picas, agates, points, millimeters, centimeters, degrees, or decimal inch measurements. Any measurement system that divides the A and B points (no matter what the distance apart) accurately into the number units you desire. So I assume 360 degrees was chosen in order to make it accurate enough to point in as many different directions as reasonable that people can easily grasp.
Fatefully_Relevant · -1 points · Posted at 12:12:24 on January 9, 2016 · (Permalink)
The circle was divided into 360 parts for purposes of astronomy. Stars and planets were observed to move nightly so the circle was divided by the days of the year. Yes. there are 365 days in a year. But then they would have problems of division. A "correction" factor was likely applied..
ers-in · -9 points · Posted at 14:19:11 on January 9, 2016 · (Permalink)
no it's not!, because a circle have 4 x 90° degree vertical angles in it so it must be 360°. Now the question is: 90° is that arbitrary ?
bugi_ · 3 points · Posted at 15:57:59 on January 9, 2016 · (Permalink)
You proved nothing here
My_usrname_of_choice · 2 points · Posted at 18:35:59 on January 9, 2016 · (Permalink)
Define 90°
justinthejoiner · -8 points · Posted at 14:34:42 on January 9, 2016 · (Permalink)
It's because there are 360 days in a year.
60 is an awesome number. You can divide it by 1,2,3,4,5,6,10,12,15,20,30,60.
But equal divisions are overrated.
I'm a big proponent of the metric system, living in the US :(
utini1 · 3 points · Posted at 14:45:28 on January 9, 2016 · (Permalink)
Um, there are 365 days in a year...
Random_Pandas · 1 points · Posted at 14:52:16 on January 9, 2016 · (Permalink)
I think HE thinks hes in r/shittyaskscience
Gugu42 · 1 points · Posted at 15:05:12 on January 9, 2016 · (Permalink)
That's why
justinthejoiner · 1 points · Posted at 23:21:29 on January 10, 2016 · (Permalink)
Thank you doctor.