Today marks the 194th birthday of Léon Foucault, the French physicist who used a pendulum to confirm the rotation of the Earth. Today's Google Doodle pays tribute.
The interactive doodle is based on the Foucault pendulum, a device introduced in 1851 to confirm the long-held assumption that the Earth spins on its axis.
Foucault's most famous pendulum consisted of a 62-pound (28 kg) brass-coated lead bob with a 220 foot (67 meters) long wire that hung from the dome of the Pantheon in Paris. This pendulum completed a full circle once every 32.7 hours, swinging clockwise at 11 degrees per hour.
Photo credit: Arnaud.
Google's pendulum doodle allows users to manipulate the virtual swinging bob according to where on Earth they happen to be.