It's fun to make one of these: use two metal coffee cans, suspend a washer between them using string tied on a plastic comb or something. There should be only

It's fun to make one of these: use two metal coffee cans, suspend a washer between them using string tied on a plastic comb or something. There should be only a small gap between the washer and each can. Charge one of the cans- rub styrofoam on fabric then touch it to one of the cans. The washer will swing back and forth, transferring the charge from the can you touched to the other one. It makes quite a racket. You can make a chain of these.