Brain on Fire Tim McCormack, distilled.

In Chemistry class today we talked about forms of energy. I've always been a little irked by the notion that there are two main forms of energy, kinetic and potential, but it's never been annoying enough to grab my focus. Today, however, I formed a definition of kinetic energy that puts it squarely within the realm of potential energy.

Why are metals always gray or yellow? Why not other colors, like red, or green, or blue?