Year of 2017

The Foucault pendulum at the Griffith Observatory in Los Angeles

French physicist Léon Foucault first demonstrated his pendulum experiment in 1851 in Paris. Since then, it’s become a mainstay of science centers and museums around the world. His simple, elegant device—little more than a weight on a wire, with suspending hardware that allows the pendulum to swing in any direction—is considered the first to prove the rotation of the Earth on its axis. This Foucault pendulum swings in the central rotunda of the Griffith Observatory in Los Angeles.

The Foucault pendulum, or Foucault’s pendulum, named after the French physicist Léon Foucault, is a simple device conceived as an experiment to demonstrate the rotation of the Earth. While it had long been known that the Earth rotates, the introduction of the Foucault pendulum in 1851 was the first simple proof of the rotation in an easy-to-see experiment.
Inventor: Léon Foucault
Pendule de Foucault
Foucault’s pendulum in the Panthéon, Paris