PURPOSE: To demonstrate conservation of energy in a simple system.

DESCRIPTION: The pendulum is hung from the upper peg with the lower peg interrupting its swing to the right. When started from the left at a given height, the pendulum rises to that same height on the right, after being stopped by the lower peg.

SUGGESTIONS: See Question of the Week #109 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 1M40.15)

EQUIPMENT: Galileo's pendulum, as photographed.

SETUP TIME: None.