There was an art accident recently. A man fell into a black hole—OK, not that kind of black hole, but an art exhibit consisting of an 8-foot-deep circular hole painted black. The idea was to represent the feeling of a super deep, even endless hole. I guess the guy didn't realize it was a hole and fell. But this leads to some great physics ideas to discuss about vision and the color black. Let me start with one of my favorite party questions. It goes like this.