Foucault's Pendulum - Significance, History, and Role in UPSC Notes | Testbook.com

Unveiling the Mystery of Foucault’s Pendulum

The Foucault’s pendulum, named after the French scientist Leon Foucault, is a fascinating scientific instrument. It comprises a heavy object suspended from a long string, capable of swinging in any direction.

• The experiment is a simple yet powerful demonstration of the earth’s rotation.
• In 1851, when Foucault presented this experiment to the public, it served as the first direct visual proof of the earth's axial rotation.

Tracing the History of Foucault’s Pendulum

• The first Foucault pendulum was created by French physicist Jean-Bernard-Léon Foucault in Paris in 1851.
• The experimental setup involved suspending a heavy object at a height using a string, allowing it to swing freely in all directions.
• The experiment proved that the pendulum’s plane of motion remains unaffected by the changes in the ground beneath it.

Key Features of Foucault’s Pendulum

• The pendulum also rotates relative to the surface of the Earth .
• When positioned at the north and south poles along the Earth's axis, the pendulum returns exactly to its initial position in 24 hours.
• The pendulum completes one full rotation in approximately 49 hours, 59 minutes, and 18 seconds.

The Working Principle of Foucault’s Pendulum

• A Foucault pendulum is a captivating device that oscillates back and forth within a specific plane.
• As a result, the pendulum's plane, when observed from above, appears to rotate once every day in a clockwise direction.
• In the Southern Hemisphere, a Foucault pendulum consistently rotates anticlockwise, while in the Northern Hemisphere, it consistently rotates clockwise.
• The rotation rate is influenced by the latitude. An ideal Foucault pendulum does not rotate at the Equator (0° latitude).

The Presence of Foucault’s Pendulum in the New Parliament

Source: Hindustan Times

• The pendulum, installed in the new Parliament building, was produced by the National Council of Science Museum (NCSM) in Kolkata.
• Suspended from a skylight at the top of Constitution Hall, the pendulum symbolizes the “integration of the idea of India with the idea of the cosmos”.
• The pendulum is the largest of its kind in India, with a height of 22 metres and a weight of 36 kilograms.
• A circular installation has been specially designed for the pendulum’s movement, surrounded by a short grill that allows visitors to gather around it.