PURPOSE: To demonstrate a variety of fluid mechanics phenomena, including the compressibility of a gas, the incompressibility of water, Boyle's law, Pascal's law, and Archimedes' law.

DESCRIPTION: The diver is carefully weighted with water. When the rubber membrane on the top of the tube is pressed, the air in the diver is compressed, allowing enough water to enter the tube that its average density becomes greater than that of water, and the diver sinks. When the membrane is released the diver again rises to the top of the tube.

SUGGESTIONS:

EQUIPMENT: Tube with diver pop bottle demo.

SETUP TIME: 15 min.