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Lessons by 3blue1brown

3blue1brown.com

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Re: Lessons by 3blue1brown

#51

Post by jameshart »

eimrine wrote: post #33
pdpi wrote: post #19

Earlier quoted context omitted.

My "ten minutes to understand something I never quite got" moment was his video on Fourier Transforms.

Just listen to some music with spectrum visualization, this is a Fourier transform of what you are listening right now.

That doesn’t provide the full understanding you might think it does. For example: define ‘right now’.

Instantaneously, music is a single sound pressure measurement. That doesn’t have a Fourier transform. It doesn’t have a frequency. It’s just a single sample.

Fourier transforms work on functions. Typically functions in the time domain. And typically (but not always) on that function within a bounded range of time. And the result is another function, this one of frequency.

A spectrum analyzer, though, is showing the Fourier transform of a short snippet of some music. Then a moment later it’s showing you the transform for the next snippet.

Looking at a spectrum analyzer makes you think a Fourier transform is itself a function of time (to some vector of numbers perhaps?). That is not the case. So looking at a spectrum analyzer can give you an incorrect intuition for what Fourier does.

But you can do a Fourier transform on the whole of a piece of music. You’ll pick up frequency components like the overall beat, the bar structure, the verse/chorus alternation.

Re: Lessons by 3blue1brown

#52

Post by seanw444 »

RichieAHB wrote: post #17

I feel like the Manim[1] library Grant created to make these videos is becoming some sort of "video matplotlib". I've seen it used in so many maths videos up to this point. There seems like a good amount of value in creating a simple, structured and clear way to represent these concepts in videos. [1] https://www.manim.community/

I never knew he made a whole open source project for it, nor that it was even a library doing the animation. I thought he hand-animated his videos. Brilliant.

Re: Lessons by 3blue1brown

#53

Post by remus »

jonahx wrote: post #31
dingosity wrote: post #7

2b1b does a video on how you raise e to a matrix (hint: raising something to e is converted into another function where it's not nonsensical to do such a thing.) In about 10 minutes he explains something my math methods instructor struggled with over two weeks (4 classes). I was resistant to the view that YouTube could host "decent" instructional content for a long time. That video was one of the first that was CLEAR…

I've had math instruction at the undergraduate and graduate level at top universities, with good instructors that I liked, and I can say without question YouTube is superior. There are many channels with outstanding content. This video is not an outlier.

Personally I don't think it is so clear cut. The value of in-person instruction is in being able to ask questions, and a good instructor will then adapt the content to help answer your questions and give you a rounded understanding of the material. Youtube videos are amazing in several respects (thinking of the reach and production value of 3b1b, for example), but being able to ask questions of a knowledgeable expert is valuable imo.

Re: Lessons by 3blue1brown

#54

Post by liorben-david »

Let me preface what I'm saying by just expressing gratitude to 3b1b for making an amazing math animation library, getting tons of people excited about math(Including me), and producing some really great videos to give people intuition.

All that being said, I've found that 3b1b videos tend to bound the intiution you can get on a topic. Most of his videos tend to reframe an idea in some sort of interesting way that can be easier to grasp without rigirous definitions and theorems. If your goal is to just understand the ground level of the idea, then this intutition is really great.

I've found that this "visual" intuition becomes unhelpful as soon as you try to grapple with a more advanced version of the topic. Your understanding of the topic is often completely limited to the way he frames it, and becomes quite useless when you leave that limited framing. He doesn't teach you "fourier transform", he teaches you a very specific context of the fourier transform which doesn't generalize well.

Again, this is still super valuable if you just want a broad understanding, but not particularly helpful for a comprehensive education of a topic.

Re: Lessons by 3blue1brown

#55

Post by veltas »

jackling wrote: post #2

I'm likely in the minority, but I found 3blue1brown videos difficult to understand and they usually give me a worse intuition about a concept than I previously had. I wonder why that is. Seems like most people I know swear by his videos.

No shame in that, I love his videos but I think it's well established that there are different kinds of learners out there. His content matches what works for me, and it's worth reminding people like me that one size doesn't fit all. But for those he does speak to, he is a fantastic teacher worthy of the praise he gets.

Re: Lessons by 3blue1brown

#56

Post by xpe »

liorben-david wrote: post #54

Let me preface what I'm saying by just expressing gratitude to 3b1b for making an amazing math animation library, getting tons of people excited about math(Including me), and producing some really great videos to give people intuition. All that being said, I've found that 3b1b videos tend to bound the intiution you can get on a topic. Most of his videos tend to reframe an idea in some sort of interesting way that can…

> I've found that this "visual" intuition becomes unhelpful as soon as you try to grapple with a more advanced version of the topic. Your understanding of the topic is often completely limited to the way he frames it, and becomes quite useless when you leave that limited framing.

Can you give a specific example?

Re: Lessons by 3blue1brown

#57

Post by beambot »

remus wrote: post #53
jonahx wrote: post #31

Earlier quoted context omitted.

I've had math instruction at the undergraduate and graduate level at top universities, with good instructors that I liked, and I can say without question YouTube is superior. There are many channels with outstanding content. This video is not an outlier.

Personally I don't think it is so clear cut. The value of in-person instruction is in being able to ask questions, and a good instructor will then adapt the content to help answer your questions and give you a rounded understanding of the material. Youtube videos are amazing in several respects (thinking of the reach and production value of 3b1b, for example), but being able to ask questions of a knowledgeable expert…

From my experience at a R1 school, this is only true for late-undergrad and grad classes, not early-stage coursework with massive student-to-teacher ratios. In those courses, you are more likely to get Q&A time with a TA during office hours. So perhaps a YouTube+TA would be better model. Bonus is that you can rewatch lectures again & again until things click.

Re: Lessons by 3blue1brown

#58

Post by seanw444 »

CogitoCogito wrote: post #35
JackFr wrote: post #29

Earlier quoted context omitted.

Professor I had for Real Analysis (the second time I took it) was probably the best math professor I've ever had. He had the most extensive mental catalog of the wrong ways people could understand and the failure modes of students. When you would ask a question he was able to help, not just because he understood the material, but because he knew why you didn't. In my evaluation of him I mentioned this, but added that…

> He had the most extensive mental catalog of the wrong ways people could understand and the failure modes of students. Back when I used to teach math classes as a grad student, I realized that a teacher has to actively work to keep that "mental catalog" for students. The problem is that longer you are in the math world, the clearer the subject becomes. The result is that to you the teacher it really just becomes bra…

I think that applies to many topics. Maybe math more than others due to the complexity of it all, but it seems commonplace that as you become more of an expert on a topic, the more detached from "newbyism" you become. It's harder to put yourself in the shoes of a beginner to see what they're seeing and know what they're missing.

Re: Lessons by 3blue1brown

#59

Post by TRiG_Ireland »

haberman wrote: post #38

I would love it if some of these educational YouTube videos came with exercises. I watch a lot of educational YouTube videos. But I've come to see them as more entertainment than education. Not in terms of the quality of the videos (which is often excellent), but in terms of what I retain. Sometimes I come across YouTube videos that YouTube claims I have watched, and I don't remember the first thing about them. I thi…

I've heard it described as "sit back" vs "sit forward" learning.

Re: Lessons by 3blue1brown

#60

Post by password54321 »

jackling wrote: post #2

I'm likely in the minority, but I found 3blue1brown videos difficult to understand and they usually give me a worse intuition about a concept than I previously had. I wonder why that is. Seems like most people I know swear by his videos.

I actually believe a lot of people feel the same way but watch anyway because of the entertainment value the animations provide. But it really has made me realise that good animations alone really aren't enough and have found dry pieces of text from wikipedia to be better at times.
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