Published on: June 4, 2023

Foucault’s pendulum

Foucault’s pendulum

Why in news? The newly inaugurated Parliament has a unique device called Dubbed Foucault’s pendulum, installed by the National Council of Science Museums


  • It is being claimed to be the largest such pendulum in the country standing at 22 meters in height.

What is Foucault’s pendulum?

  • Foucault’s pendulum is an experimental scientific device that demonstrates the rotation of the Earth.
  • Since we cannot feel the rotation of Earth the device provides visual evidence of the astronomical event as it rotates at a speed of nearly 1,670 kilometers per hour.
  • The pendulum was introduced in 1851 and was designed by French physicist Léon Foucault.

How does Pendulum works?

  • It works by the conservation of angular momentum.
  • The pendulum’s axis of rotation is initially aligned with the Earth’s axis of rotation.
  • As the Earth rotates, the pendulum’s axis of rotation remains fixed in space, so it appears to rotate around the Earth.
  • The period of rotation of the pendulum depends on the latitude of the pendulum and the length of the pendulum.
  • The exact rate at which the plane of the pendulum’s swing appears to rotate depends on the latitude at which it is located.

At the North Pole, for example, the plane of the swing will complete a full rotation in 24 hours, while at the equator, there will be no observable