Simply moisten the bird’s head with water, place it next to a full glass of water and watch as the bird periodically dunks its head into the glass for a “drink.” It continues for hours. Great centerpiece for class discussion or laboratory exploration. How does it work? Is it really perpetual motion? Does it work better with hot or cold water? Does it work in an enclosed space, such as an inverted aquarium? Each bird comes complete with an explanation for teachers and suggested experiments. 6 in. tall.