A Foucault pendulum swings inside the new Parliament

Source: The post is based on the article “A Foucault pendulum swings inside the new Parliament” published in The Hindu on 29th May 2023

What is the News?

The new Parliament building’s one of the key features includes a Foucault pendulum suspended from its ‘Constitutional Gallery’ area. It was designed and installed by the National Council of Science Museums (NCSM), Kolkata.

What is a Foucault pendulum?

It is a deceptively simple device used to illustrate the earth’s rotation.

Founded by: The Foucault pendulum is named for Léon Foucault (1819-1868), the French physicist who devised the apparatus in the 19th century.

How does the Foucault pendulum function?

The pendulum consists of a bob suspended at the end of a long, strong wire from a fixed point in the ceiling.

As the pendulum swings, the imaginary surface across which the wire and the bob swipe is called the plane of the swing.

For instance,

Foucault pendulum
Source: Schoolphysics

a) If the pendulum is installed at the North Pole, it will basically be swinging as the earth rotates ‘below’, b) If the pendulum is installed over the equator, the plane won’t appear to shift at all because it will be rotating along with the earth, and c) On any other latitude, the plane will shift through 360 degrees in “one sidereal day divided by the sine of the latitude of its location

A Foucault pendulum is not easy to set up. It must be designed, installed, and set swinging in such a way that the bob’s motion is influenced to the extent possible only by gravity.

Note: In 1991, the then-new Inter-University Centre for Astronomy and Astrophysics, Pune, commissioned the country’s first Foucault pendulum for public display from the NCSM. After several studies and failed tests, the NCSM installed the set-up in 1993. 

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