We are having a discussion on the street. It's a question about physics, but I can't bring it back to save me. Very technical and a revelation to me. I am with son Casey, and his science teacher in high school is our ah hoc instructor.

He holds out his hand. Casey laughs, and we pass on. I realize...he's now a mendicant street professor. He must beg of pedestrians, and his busking gig is science. He is neatly dressed for a wandering science beggar, but a little slipshod for a teacher. He was a very funny guy in school; everyone liked Boomer. (This isn't him; it's someone playing him.)

We pretend he's kidding, leave him on the street, forms passing in all directions. He smiles, and allows the outhrust hand to be ironic if we like. But he isn't kidding.

I don't like it. First you think, a scientist, you'd insult him by giving chump change. Then, do you not humiliate him more by ignoring his request?

I never know. I'm no good in these matters. I never studied science.