Foucault pendulum Facts for Kids

Foucault's Pendulum in the Panthéon, Paris.

The Foucault pendulum, or Foucault's pendulum (named after the French physicist Léon Foucault) was created as an experiment to show the rotation of the Earth.

Images for kids

Foucault's pendulum in the Panthéon, Paris
A Print of the Foucault Pendulum, 1895
Animation of a Foucault pendulum on the northern hemisphere, with the Earth's rotation rate and amplitude greatly exaggerated. The green trace shows the path of the pendulum bob over the ground (a rotating reference frame), while in any vertical plane. The actual plane of swing appears to rotate relative to the Earth: sitting astride the bob like a swing, Coriolis fictitious force disappears: observer is in a "free rotational" reference where, according to general relativity, non-Euclidean curved spacetime metrics must be used. The wire should be as long as possible—lengths of 12–30 m (40–100 ft) are common.
A Foucault pendulum at the North Pole: The pendulum swings in the same plane as the Earth rotates beneath it.
An excerpt from the illustrated supplement of the magazine Le Petit Parisien dated November 2, 1902, on the 50th anniversary of the experiment of Léon Foucault demonstrating the rotation of the earth.
The animation describes the motion of a Foucault pendulum at a latitude of 30°N. The plane of oscillation rotates by an angle of −180° during one day, so after two days, the plane returns to its original orientation.
The device described by Wheatstone.
Foucault pendulum at the Musée des Arts et Métiers
Foucault pendulum at the Ranchi Science Centre
Foucault pendulum at the California Academy of Sciences
Foucault pendulum at the Devonshire Dome, University of Derby