Foucault Pendulum
  • noun
    (written as Foucault pendulum)
    a heavy pendulum suspended by a long thin wire that can swing in any direction
  • A long pendulum set to swing with a heavy weight at its extreme end. If set up with adequate care, a Foucault Pendulum can be seen to rotate once a day through a full circle as the Earth turns beneath it, providing simple and powerful proof of the Earth’s rotation. Invented by Leon Foucault (1819–1868), French physicist.

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