Definition:Foucault's Pendulum

Definition

Foucault's pendulum is an experiment for demonstrating the rotation of Earth about its axis.

It consists of a long pendulum (of the order of tens of metres) with a heavy bob (of the order of tens of kilograms.

Such a pendulum is set in motion with a small (of the order of tens of centimetres) and left to swing.

It is seen that the bob swings in a plane, tracing a straight line on the floor beneath.

As Earth rotates about its axis, the plane of swing remains constant.

Hence the plane of swing appears to slowly rotate in the opposite direction to that of Earth.

Also known as

Foucault's pendulum can also be styled as the Foucault pendulum.

Also see

• Results about Foucault's pendulum can be found here.

Source of Name

This entry was named for Jean Bernard Léon Foucault‎.

Historical Note

Foucault's pendulum was demonstrated by Jean Bernard Léon Foucault in $1851$, with a $28 \, \mathrm {kg}$ bob at the end of a $67 \, \mathrm m$ length of wire inside the dome of the Panthéon in Paris.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): Foucault's pendulum
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): Foucault's pendulum