Why Is the Sky Blue the Answer?

Richard Feynman had an interesting philosophy of question asking. I like how really simple questions you can kind of keep drilling into them and, and find more unanswered questions. Until very recently we did not really understand why ice was slippery and why ice gains worked. We've got a rough understanding of what happens on the surface of ice that makes metal skates slide on it. There are some fun questions like, um, if you've ever tried taking a pair of pliers and crushing a sugar cube in the dark, there's a flash of light.