Foucault's Pendulum [UPSC Notes]

India’s newly inaugurated Parliament building boasts of a new installation called the ‘Foucault’s Pendulum’. In this context, we must understand what Foucault’s Pendulum is, what are its scientific significance and other details from the perspective of the IAS exam science and technology segment.

What is the Foucault’s Pendulum?

Foucault’s pendulum is an engaging scientific instrument that consists of a hefty object suspended from a long string and can swing in any direction. 

• It is a simple experiment to demonstrate the earth’s rotation, which is originally named after 19th-century French scientist Leon Foucault. 
• When Foucault carried out this experiment for the public in 1851, it was the first direct visual evidence of the fact that the earth rotates on its axis.

Foucault’s Pendulum History

• The first of these pendulums was made by French physicist Jean-Bernard-Léon Foucault in Paris in 1851. 
• A heavy object was suspended at a height using a string in the experimental setup to allow for unfettered swinging in all directions. 
• According to the experiment results, the pendulum’s plane of motion is unaffected by changes in the ground underneath it. 

Significant Characteristics of Foucault’s Pendulum

• With respect to the surface of the Earth, it also rotates.
• The pendulum returns precisely to its starting position in “24 hours” when it is positioned at the north and south poles along the axis of the Earth.
• The pendulum completes one full rotation in a total time of 49 hours, 59 minutes, and 18 seconds.

How Does It Work?

• A Foucault pendulum is an intriguing device that swings back and forth within a particular plane. 
• As a result, the plane of the pendulum, as seen from above, seems to rotate once every day in a clockwise direction. 
• A Foucault pendulum rotates constantly anticlockwise in the Southern Hemisphere and always clockwise in the Northern Hemisphere.
• The latitude affects the rotation rate. An equilibrium Foucault pendulum does not revolve at the Equator (0° latitude).

Foucault’s Pendulum in New Parliament

Source: Hindustan Times

• The National Council of Science Museum (NCSM) in Kolkata produced the pendulum which was mounted in the new Parliament building.
• The pendulum, which hangs from a skylight at the top of Constitution Hall, represents the “integration of the idea of India with the idea of the cosmos”.
• The pendulum is the biggest of its kind in India and measures 22 metres tall and weighs a hefty 36 kilograms.
• A circular installation has been created expressly for the pendulum’s movement, and it is complemented by a short grill that enables guests to congregate around it.

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