In 1851, when French physicist Léon Foucault performed his pendulum experiment in Paris, he became the first to prove what many scientists of his day already suspected—that the Earth spins on an axis. He conducted his first experiments 170 years ago, in early January 1851, with a relatively small prototype in the cellar of his home. Just a month later, Foucault performed his most famous pendulum demonstration, using a 62-pound spherical weight attached to a 220-foot wire, which was hung from the dome of the Panthéon, a Parisian monument. As the pendulum swung back and forth in a fixed plane, the pointed end of the weight traced lines in a compass-like circle of sand below it. As time passed, the angle of these lines began to change, demonstrating to onlookers that the Earth itself was rotating underneath the pendulum, and by extension, everyone watching was rotating as well, spinning on the surface of the great blue marble around its axis.
Take this for a spin...
Today in History
More Desktop Wallpapers:
-
Bardenas Reales Biosphere Reserve and Natural Park, Spain
-
Naxos in the Cyclades Islands of Greece
-
Balloons and camels are two ways to catch a ride here
-
Children at play for International Day of Friendship
-
Celebrating the Acadians
-
Tiny fliers head south
-
Spotted Lake emerges
-
Protecting Alaska
-
World Elephant Day
-
Northern hawk-owl
-
Audubon Christmas Bird Count
-
A picture-perfect day on Trillium
-
Brown bears in Lake Clark National Park and Preserve, Alaska
-
Don t forget—it’s World Elephant Day
-
Palazzo Zuccari, Rome
-
International Mountain Day
-
Wake up, it s Darwin Day
-
Star Wars Day
-
Greece celebrates its independence
-
Happy Canada Day!
-
Craig Goch Dam in the Elan Valley of Wales
-
Antarctica Day
-
Badlands National Park turns 44
-
Celebrating whales—and a whale of a tale
-
Castle on a hill
-
World Architecture Day
-
World Lizard Day
-
World Reef Day
-
Grandparents Day
-
National Mushroom Day
Bing Wallpaper Gallery

