Entertaining, fascinating and almost hypnotic to watch. Dip the bird’s beak into a glass of water, and you will set it in motion. The bird will start to dip its head lower and lower, until it appears to drink. It will then raise its head, and start the cycle again. Although it may look like a perpetual motion, this curiosity is actually caused by a heat engine. As long as you make sure the beak can get wet, the bird will continue to drink.