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Foucault Pendulum

Foucault Pendulum

One of SCI's most iconic and beloved experiences, the Foucault Pendulum is a 235-pound, 17-inch brass ball demonstrating the rotation of the earth, which previously hung for more than 30 years in the Science Center of Iowa's former location in Greenwood-Ashworth Park.

The pendulum was first devised in 1851 by the French physicist Leon Foucault, who suspended a large iron ball and set it swinging along a north-south line. Spectators saw it slowly turn in a clockwise direction. They were in fact observing the counter-clockwise motion of the Earth under the invariable swing of the pendulum.

SCI's pendulum is suspended from the ceiling by a 41-foot-long cable where a circular electro-magnet keeps it swinging indefinitely in a 7.5-foot arc and knocking over two of the 427 steel pegs surrounding the frame of the pendulum every five minutes.

Located on SCI’s Main Level near the IMAX lobby.