Léon Foucault’s pendulum illustrated in interactive Google Doodle

18 Sep 2013

Léon Foucault's pendulum doodle on the Google homepage

Today, Google’s homepage honours French physicist Léon Foucault on what would have been his 194th birthday with an interactive animation of the Foucault pendulum in action.

Born 18 September 1819 in Paris, Foucault originally studied medicine but a fear of blood drove him to physics.

The scientific world is grateful for that decision as, in 1851, Foucault devised the first easy-to-see demonstration of the rotation of the Earth and his concept sparked a wave of ‘pendulum mania’.

Foucault publicly demonstrated his pendulum experiment at the Panthéon in Paris using a heavy weight suspended from the roof on a 36-foot wire. The swinging pendulum showed that the plane of oscillation would revolve about 270 degrees in 24 hours, thus demonstrating the rotation of the Earth.

Following Foucault’s experiment, similar pendulums were installed in major cities across Europe and the US, attracting crowds to witness and understand the effect of the Earth’s rotation. Foucault pendulums are still a popular installation in museums and universities – and, at least for today, on Google’s homepage.

The interactive animated pendulum is activated by clicking the doodle. The buttons to the right of the animation call up sliders to control the swinging of the pendulum relative to different locations on Earth. There’s also a search button to bring you to results for ‘Léon Foucault’.

What the Foucault pendulum demonstrates – apart from the Earth’s rotation, of course – is the importance of communicating complex ideas in ways that the general public can visualise, thus sparking a broader understanding of the world around us.

Among other things, Foucault also discovered eddy currents and is credited with naming the gyroscope, which is used today in compasses, aircraft, computer pointing devices and other consumer electronics. He also invented a polariser and devised a test to determine the shape of the mirror of a reflecting telescope called the Foucault knife-edge test, which is still used today.

He died aged 48 on 11 February 1868 and his name is among 72 scientists, engineers, and mathematicians engraved on the Eiffel Tower.

Elaine Burke is the host of For Tech’s Sake, a co-production from Silicon Republic and The HeadStuff Podcast Network. She was previously the editor of Silicon Republic.