Why Light Travels Slower in Glass
Sixty Symbols · Explainer · 17 min · 2013 · YouTube title: Why is light slower in glass? - Sixty Symbols
Why it's here
HN cites it whenever the popular absorb-and-re-emit explanation comes up, as a source for the wave-interference account.
What it covers
Professor Mike Merrifield of Nottingham explains in a mostly uncut conversation why light travels slower in glass. He treats light as a wave and describes how the material's electrons produce secondary waves that combine to slow it.