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:
-
Overseas Highway, Florida Keys
-
Islands of the Salish Sea
-
Best fronds forever
-
Happy New Year!
-
Class, please take out a No. 2 pencil…
-
World Elephant Day
-
Maybe we should be looking up
-
Storseisundet Bridge, Norway
-
Siblings Day
-
Village of Saranac Lake, New York
-
Honoring the rangers on World Ranger Day
-
International Day of Human Space Flight
-
Gentoo penguins in Antarctica
-
Life in a North African town
-
Let the harvest begin
-
Spectacular views below!
-
Oh, to sleep under the northern lights
-
Celebrating migrations
-
Zion National Park turns 103
-
Bird’s-eye view of the Golden Gate Bridge, San Francisco, California
-
International Women s Day
-
Hello, harbinger of spring
-
Porto Cathedral, Portugal
-
‘The mountains are calling’
-
World Parrot Day
-
A stroll above the stratosphere
-
Singing praises of the oceans
-
Composite of photographs from the Apollo 15 mission
-
World Jellyfish Day
-
Edinburgh Art Festival
Bing Wallpaper Gallery

