Why light can “slow down”, and why it depends on color | Optics puzzles 3

How the index of refraction arises, and why it depends on color. Quotebook Notebooks: These lessons are primarily funded directly by viewers: An equally valuable form of support is to simply share the videos. Looking Glass Universe videos on the index of refraction: Much of this video is based on the following Feynmann lecture 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: 0:00 - The standard explanation 3:14 - The plan 5:09 - Phase kicks 8:25 - What causes light? 13:20 - Adding waves 16:40 - Modeling the charge oscillation 20:59 - The driven harmonic oscillator 26:57 - End notes Thank you to @doryhelioaires for Portuguese subtitles ------------------ These animations are largely made using a custom Python library, manim. See the FAQ comments here: #manim All code for specific videos is visible here: The music is by Vincent Rubinetti. ------------------ 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. Mailing list: Twitter: Instagram: Reddit: Facebook: Patreon: Website: