For showing potential energy stored in a wound-up steel spring and its conversion to electrical energy by driving a dynamo and lighting a lamp. May also be used to wind up a mass on a cord showing the change from potential energy to kinetic and back to potential in the raised mass. The steel shaft carries a wound steel spring strip with
a free wheel device and winding ratchet also a pulley. One end of the shaft overhangs the base for use as a line shaft when winding up a mass.Supplied complete with driving belt.
