Mesmerizing and addictive!
More than an elegant desktop execu-toy (although it is that too!) the Pit and Pendulum demonstrates real science.
Secured in its oak stand, 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" ever changing geometric patterns in the sand. The patterns get bigger then smaller then bigger again as the arc of the pendulum also changes.
Comes with a 23" stand with bowl-type base, bag of sand, and instructions.