But why would light "slow down"? | Optics puzzles 3

Part of what makes Grant such a superlative educator is how he treats the things he leaves out or simplifies. He always points them out, explains why he's skipping over them, and provides a hint as to what including them would look like. It's never "It's too complicated, just don't worry about it."

I teach optics in the University, and I can say that you nailed this one, really the best explanation I've ever seen on the matter. I'm sure Feynman would hug you if he could see this video.

If there was a Nobel Prize for explanations, you would be my canditate. Thank you for taking the trouble to explain things so profoundly and vividly. You are my hero.

"so, everything was just a harmonic oscillator?" "always has been." Great video as always. Waiting for the next part!

I'm genuinely telling you Grant, for all the human beings seeking the absolute deepness of reality asking every bit of "Why", you are an unprecedented blessing.

this is the clearest explanation I ever heard. It's like 15 optics lectures condensed in a single video. Absolutely mind blowing...

I have always regretted my lack of math education. The equations in the video barely make sense - the algebra makes sense but the differential equation stuff is a language I just don't speak - so seeing the visuals to explain these things make them accessible to me. Thanks. And those visuals are absolutely stunning!

I always wondered what Feynman's lectures would have been like if he taught them with today's technology, and man this is it. The world is going to have some brilliant physicists and mathematicians thanks to you.

After a double major in math and physics, I'm doing a PhD in physics. A great part of it deals with light-matter interaction. I must say this is a beautiful representation of a phenomenon that most of the time physicists "sort of" imagine. Thanks for such a great way of visualizing physics! And thanks for giving our dear harmonic oscillator the visibility it deserves!

I was genuinely thinking about working on prisms an hour ago as an electromagnetism exercise, this is too perfect to be true.

This may be one of the first 3b1b videos I actually understood, wonderful job. Also it is kind of adorable thinking that Grant approached his niece like 'can I push you in a swing for a math video, but like, really badly'

This video reminded me of a talk I had with some friends at CERN, where I told them that we didn't really understand why light refracts, the typical explanations weren't enough. When I looked into it myself, I remember reading the response in the Feynman Lectures and being more or less pleased with what it said. But now with the video and animations everything clicked! From a question I had asked myself ten years ago, it is an incredible sensation! Thank you Grant.

The animations in this video are clarifying so many details that are very hard to explain in any other way. Fantastic, I loved every second of it!

22:11 my favorite 3b1b moment thank you Grant for your works it has been monumental to my studies

13 minutes in and you’ve already granted 3 revelations in my understanding of our world that would have otherwise taken years for me to understand… you have a very special talent and I thank you massively.

I don't think there is a material on youtube or the internet explaining this stuff in such detail and so comprehensibly. I am blown away. It instantly clicks!

The single best channel on this entire site. I wish I had money to spare, because you, mister, deserve it more than anyone. Brilliant video, brilliant editing, brilliant visuals, brilliant explanation.

Dear Grant Sanderson, You turn raw mathematics into an intuitive knowledge, helping us evole our own ideas about the physical works, with so many emergant subject to explore. You turn math into a real world experience, much like our brains must be doing when it takes measurements of this strange place around us. Thank you for the profound wisdom you share in the simplest of ways. Hats off to you, Sir! Always a fan, best regards :)

This might be my favorite physics explainer video ever, and it's on a math channel - undergrad me would be twitching =D I love this video because the animations of the phase shift and the oscillator so succinctly get the point across when it normally takes (or at least for me it took) years of imagining and trying to extrapolate from static images on a whiteboard and a lot of conflicting explanations. It's very easy to grasp small pieces of it but if you learn too many disconnected pieces that use different assumptions and approximations you end up with really pretty puzzle pieces that don't fit together. I really hope that others had the same reaction as I did - when I publish something I'm always afraid that it will only make sense to me just because I already know the material, and I think this style fights that very effectively. I'm very excited to see your explanation of "metamaterial" indeces of refraction because the explanation of why speed is bending that I know (plane waves on a 2d mesh are like your tank treads) shouldn't work with speeds faster than C. If it's a phase vs group thing I'm getting ready to be confused but I'll probably understand it better than I ever have before! wait a minute - as I type this I might be having a lightbulb - you showed the startup transient - nobody ever shows the startup transient. is that how you obey relativity but have a phase velocity >C? ahhh that would only work near resonance, which those funky capacitor loops on paper DO. oh my god. EVERYTHING IS SPRINGS 😁

Props to you for explaining topics proper of a electrodynamics/solid state physics class to a wide audience without making it confusing or hard to digest