The Foucault Pendulum was the first experimental demonstration of the Earth’s rotation on its axis. Showing the rotation of the plane of oscillation of a pendulum hung from the roof of the Pantheon in Paris, Léon Foucault’s experiment became a major attraction in 1851, and was recreated in a number of European and American cities.
Google’s logo includes a rendering of the Foucault Pendulum swinging, along with a small clock and globe icon that, when clicked, allows users to control the pendulum’s movements.
While best known for his pendulum, Foucault garnered a number of scientific achievements during his career. A year after building the original pendulum, Foucault used a gyroscope to reproduce the experiment. Even though the gyroscope had already been invented, Foucault is credited with naming the device. He also invented the Foucault Knife-Edge Test to determine if a mirror is perfectly spherical, and conducted speed of light experiments.
Awarded a Copley Medal from the Royal Society of London, Foucault was named a member of the Bureau des Longitudes, an officer of the Légion d’Honneur, and his name is inscribed on the Eiffel Tower. Foucault died at age 48 on February 11, 1868 and is buried in Paris’ Cimetière de Montmartre.