By the way, which one’s Pink?

The Factual One ponders The physics of… Pink Floyd?

What’s more interesting is the fact that the refractive index is generally not a constant. Within the same material it can be different for different wavelengths. Usually – but not quite always – higher frequency light experiences a higher refractive index. It gets bent harder. It’s not obvious at the level of classes I teach why this should be so. Since the details aren’t really the key issue, the main thing to remember whether it’s high frequency or high wavelength that gets bent most strongly. It can be difficult to remember, until I remind the class about this:

[cue Dark Side of the Moon album cover]

More discussion at The Quantum Pontiff