Leon Foucault's 194th birthday has been marked a Google doodle. Foucault was a French physicist. The interactive Google doodle showcases the Foucault Pendulum, a device which was invented by Foucault to demonstrate the effect of earth's rotation. The doodle features two toggles for time and the position on the earth. Different combinations make the pendulum knock down pins placed at at different positions. The Foucault pendulum, invented in 1851, was one of the first simple experimental proofs of earth's rotation. The original pendulum was first showcased in the Meridian of the Paris Observatory, with a 28kg brass-coated lead bob and a 67-metre long wire being hung from the dome of the Pantheon. The pendulum completed a full circle every 32.7 hours, rotating clockwise at 11 degrees every hour. Leon Foucault was born on September 18, 1819 to a publisher, in Paris. He started studying medicine but left due to his fear of blood. In his initial years he investigated subj