Today, Google celebrates French physicist Jean Bernard Léon Foucault's 194th birthday with and interactive Doodle based on Foucault pendulum, a radical device Léon created to demonstrate the effect of the earth's rotation. Since the doodle is interactive, it allows users to manipulate the movement of the pendulum according to where on earth they happen to be. One can also manipulate the pendulums movement by using the clock and globe place beside the doodle. To know more about Léon Foucault and his device, users can click the magnifying glass icon.
The Foucault pendulum is a simple device introduced in 1851 to confirm, in as basic a way as possible, the long-assumed theory that the earth rotated. Moreover, Foucault's original pendulum was first exhibited in the Meridian of the Paris Observatory, and consisted of a 28kg brass-coated lead bob with a 67-metre long wire from the dome of the Pantheon. The pendulum made a full circle once every 32.7 hours, swinging clockwise at 11 degrees per hour.
Jean Bernard Léon Foucault
Foucault was born to a publisher in Paris on September 18, 1819. He originally studied medicine, but was forced to give it up after developing a fear of blood. His career as a physicist began shortly after, assisting and collaborating with Alfred Donne and Hippolyte Fizeau. In 1850 he conducted a ground-breaking experiment that was viewed as "driving the last nail in the coffin" of Newton's corpuscle theory of light when it proved light travels more slowly through water than through air.
In 1851 Foucault caused a sensation with his famous pendulum experiment, and the following year he used and named (but did not invent) the gyroscope - a device for measuring and maintaining orientation.
In 1855 Foucault discovered that the force required for the rotation of a copper disc becomes greater when it is made to rotate with its rim between the poles of a magnet, the disc at the same time becoming heated by the eddy current or "Foucault currents" induced in the metal.
Two years later he invented the Foucault polarizer, and in 1858 devised a method of testing the mirror reflecting telescope to determine its shape, the so called Foucault knife-edge test which is still used in amateur telescopes.