Léon Foucault pendulum suspended from the roof of the Panthéon, Paris. The experiment caused a sensation in both the learned and popular worlds, and ""Foucault pendulums"" were suspended in major cities across Europe and America and attracted crowds. In the following year he used (and named) the gyroscope as a conceptually simpler experimental proof. In 1855, he received the Copley Medal of the Royal Society for his 'very remarkable experimental researches'. Earlier in the same year he was made "physicien" (physicist) at the imperial observatory at Paris. In September 1855 he discovered that the force required for the rotation of a copper
Foucault pendulum – viewed from above – undergoes a full clockwise rotation during one day; a pendulum at the South Pole rotates counterclockwise. When a Foucault pendulum is suspended at the equator, the plane of oscillation remains fixed relative to Earth. At other latitudes, the plane of oscillation precesses relative to Earth, but more slowly than at the pole; the angular speed, "ω" (measured in clockwise degrees per sidereal day), is proportional to the sine of the latitude, formula_1: where latitudes north and south of the equator are defined as positive and negative, respectively. For example, a Foucault pendulum at 30° south