Editing Foucault pendulum (section)

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{{Short description|Device to demonstrate Earth's rotation}}
{{About|the physics experiment and instrument|the novel by Umberto Eco|Foucault's Pendulum}}
[[File:Panthéon Pendule de Foucault2.JPG|thumb|upright=1.15|Foucault's pendulum in the [[Panthéon]], [[Paris]]]]
The '''Foucault pendulum''' or '''Foucault's pendulum''' is a simple device named after French physicist [[Léon Foucault]], conceived as an experiment to demonstrate the [[Earth's rotation]]. If a long and heavy pendulum suspended from the high roof above a circular area is monitored over an extended period of time, its [[plane (geometry)|plane]] of [[oscillation]] appears to change spontaneously as the Earth makes its 24-hourly rotation. This effect is greatest at the poles and diminishes with lower latitude until it no longer exists at Earth's [[equator]].

The [[pendulum]] was introduced in 1851 and was the first experiment to give simple, direct evidence of the Earth's rotation. Foucault followed up in 1852 with a [[Foucault's gyroscope experiment|gyroscope experiment]] to further demonstrate the Earth's rotation. Foucault pendulums today are popular displays in [[science museum]]s and universities.<ref>{{cite journal|author=Oprea, John|title=Geometry and the Foucault Pendulum|journal=Amer. Math. Monthly|volume=102|issue=6|year=1995|pages=515–522|url=http://www.maa.org/programs/maa-awards/writing-awards/geometry-and-the-foucault-pendulum|doi=10.2307/2974765|url-status=live|archive-url=https://web.archive.org/web/20150402122208/http://www.maa.org/programs/maa-awards/writing-awards/geometry-and-the-foucault-pendulum|archive-date=2015-04-02|jstor=2974765|url-access=subscription}}</ref>