Google Doodle celebrates French physicist Léon Foucault’s 194th birthday with pendulum tribute

Foucault pendulum is a simple device introduced in 1851 to confirm that the earth rotated

John Hall
Tuesday 17 September 2013 15:40 BST
Comments
(Google)

Your support helps us to tell the story

From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it's investigating the financials of Elon Musk's pro-Trump PAC or producing our latest documentary, 'The A Word', which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging.

At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.

The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it.

Your support makes all the difference.

The interactive doodle is based on the Foucault pendulum - a radical device he created to demonstrate the effect of the earth’s rotation - and allows users to manipulate the swinging bob according to where on earth they happen to be.

The Foucault pendulum is a simple device introduced in 1851 to confirm, in as basic a way as possible, the long-assumed theory that the earth rotated.

Foucault’s original pendulum was first exhibited in the Meridian of the Paris Observatory, and consisted of a 28kg brass-coated lead bob with a 67-metre long wire from the dome of the Pantheon. The pendulum made a full circle once every 32.7 hours, swinging clockwise at 11 degrees per hour.

Foucault was born the son of a publisher in Paris on September 18, 1819 and originally studied medicine, but was forced to give it up after developing a fear of blood.

His career as a physicist began shortly after, assisting and collaborating with Alfred Donne and Hippolyte Fizeau.

In 1850 he conducted a ground-breaking experiment that was viewed as “driving the last nail in the coffin” of Newton’s corpuscle theory of light when it proved light travels more slowly through water than through air.

In 1851 Foucault caused a sensation with his famous pendulum experiment, and the following year he used and named (but did not invent) the gyroscope – a device for measuring and maintaining orientation.

In 1855 Foucault discovered that the force required for the rotation of a copper disc becomes greater when it is made to rotate with its rim between the poles of a magnet, the disc at the same time becoming heated by the eddy current or “Foucault currents” induced in the metal.

Two years later he invented the Foucault polarizer, and in 1858 devised a method of testing the mirror reflecting telescope to determine its shape – the so-called Foucault knife-edge test which is still used in amateur telescopes.

Foucault died of multiple sclerosis on February 11, 1868 at the age of 48 after being made a member of many of the top scientific societies in Europe.

He was buried in the Cimetière de Montmartre, with his name among those of seventy-two French scientists, engineers, and mathematicians engraved on the Eiffel Tower. The asteroid 5668 Foucault is also named after him.

Click on the gallery above to see a collection of recent Google Doodles

Join our commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in