But why would light "slow down"? | Visualizing Feynman's lecture on the refractive index

How the index of refraction arises, and why it depends on color (as seen with a prism)

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This video is largely based on the following Feynmann lecture

Looking Glass Universe videos on the index of refraction:

The explanation for why the phase of a wave produced by a plane of oscillating charges is a quarter phase behind the wave of a charge in the center of that plane, and hence a quarter phase behind that of a light wave inducing the oscillations, is given in the previous chapter:

Sections:

Thanks to these viewers for their contributions to translations

German: Ole

Hebrew: Alon Altman, Omer Tuchfeld

Hindi: Saurabh

Portuguese: @doryhelioaires

Urdu: Momini0

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These animations are largely made using a custom Python library, manim. See the FAQ comments here:

All code for specific videos is visible here:

The music is by Vincent Rubinetti.

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