Portal:Philadelphia/Selected picture/August 2006

credit: Bdesham

A Foucault pendulum, named after the French physicist Léon Foucault, was conceived as an experiment to demonstrate the rotation of the Earth; its action is a result of the Coriolis effect. It is a tall pendulum free to oscillate in any vertical plane and ideally should include some sort of motor so that it can run continuously rather than have its motion damped by air resistance. The above pendulum is located in the Grand Stairwell at the Franklin Institute in Philadelphia, Pennsylvania. It was installed in 1934 and donated by Mr. and Mrs. Richard L. Binder.