The mesmerizing and addictive Pit and Pendulums are more than elegant desktop execu-toys (although they are that too!) The Pit and Pendulums also demonstrate real science. The all-metal pendulum converts kinetic energy into potential energy. The extremely fine sand (included) provides minimal friction allowing the pendulum to swing for extended periods of time. As the pendulum swings it gently "writes" everchanging geometic patterns in the sand. The patterns get bigger then smaller then bigger again as the arc of the pendulum also changes.

Dimensions:

Small: 12" x 6"

Large: 23" x 10"