Measuring an isotope of carbon to find out how old an organic object is. See 'Some Notes on Archaeology'.
Radiocarbon dating
Fact of the Day
During the gin craze in the eighteenth century, the ratio of gin shops to houses in London was as high as one to five.
Quote of the Day
"How wonderful it is that nobody need wait a single moment before starting to improve the world.
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~ Anne Frank
On This Day
1830 The Manchester to Liverpool train line opened, and caused the first train death (of MP William Huskisson).
1859 The great engineer Isambard Kingdom Brunel died.
1916 Tanks were first used on the Somme. They weren't ready for use in combat and many broke down.
1935 The Nuremberg race laws were introduced, stripping German Jews of their citizenship and forbidding them to marry Aryans.
1940 Hitler indefinitely postponed his invasion of Britain following a massive defeat of the Luftwaffe.
2008 The financial services firm Lehman Brothers filed for bankruptcy, the biggest such filing in US history, causing the Dow Jones to drop more than 500 points in a day.