Answering viewer questions about the index of refractionLessons are primarily funded directly by viewers, who get early access to new videos: https://3b1b.co/supportAn equally valuable form of support is to simply share the videos.

Much of the last video, as well as this one, is based on the following Feynman Lecture:https://www.feynmanlectures.caltech.edu/I_31.html

Looking Glass Universe videos on the refractive index:https://youtu.be/uo3ds0FVpXs?si=Q12Rgz9vN1JMo_di

Timestamps:

0:00 - Why slowing implies bending3:36 - Recap for how slowing happens5:08 - Birefringence6:19 - The barber pole8:20 - When the refractive index is less than 1

Thanks to these viewers for their contributions to translationsFrench: LE PRAT Ronan, PyStLHebrew: Omer TuchfeldPortuguese: rose ✨Russian: iverid

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These animations are largely made using a custom Python library, manim. See the FAQ comments here:https://3b1b.co/faq#manimhttps://github.com/3b1b/manimhttps://github.com/ManimCommunity/manim/

All code for specific videos is visible here:https://github.com/3b1b/videos/

The music is by Vincent Rubinetti.https://www.vincentrubinetti.comhttps://vincerubinetti.bandcamp.com/album/the-music-of-3blue1brownhttps://open.spotify.com/album/1dVyjwS8FBqXhRunaG5W5u

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3blue1brown is a channel about animating math, in all senses of the word animate. If you're reading the bottom of a video description, I'm guessing you're more interested than the average viewer in lessons here. It would mean a lot to me if you chose to stay up to date on new ones, either by subscribing here on YouTube or otherwise following on whichever platform below you check most regularly.

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