Foucault pendulum Foucault pendulum The Foucault pendulum ( ; ) or Foucault's pendulum is a simple device named after French physicist Léon Foucault and conceived as an experiment to demonstrate the Earth's rotation. The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. Today, Foucault pendulums are popular displays in science museums and universities. The first public exhibition of a Foucault pendulum took place in February 1851 in the Meridian of the Paris Observatory. A few weeks later, Foucault made his most famous pendulum when he suspended a 28-kg brass-coated lead bob
Foucault pendulum vector diagrams deduce that the time to observe a full rotation of the Earth increased by the inverse of the sine of the latitude. formula_7 = formula_8 = formula_9 The Pendulum Sine Law also defines that the ratio of the observed Earth's rotation time at two separate latitudes in relation to a pendulum swing is equal to the inverse ratio of the sine of the two latitudes. formula_10 = formula_11 = formula_12 The sine of the latitude also indicates the degree of alignment of the pendulum central axis to the Earth's axis of rotation. At the poles the pendulum axis is parallel