Answering a few viewer questions about the refractive index.
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An 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 bending
3:36 - Recap for how slowing happens
5:08 - Birefringence
6:19 - The barber pole
8:20 - When the refractive index is less than 1
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These animations are largely made using a custom Python library, manim. See the FAQ comments here:
https://3b1b.co/faq#manim
https://github.com/3b1b/manim
https://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.com
https://vincerubinetti.bandcamp.com/album/the-music-of-3blue1brown
https://open.spotify.com/album/1dVyjwS8FBqXhRunaG5W5u
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