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'''Radiocarbon dating''' is a method for estimating the age of organic material by measuring the ratio of carbon-14 to carbon-12 present.
'''Radiocarbon dating''' is a method for estimating the age of organic material by measuring the ratio of carbon-14 to carbon-12 present.
The method is based on the fact that the carbon-12 [[isotope]] of carbon is more stable, and therefore more common, than the [[radioactivity | radioactive]] carbon-14 isotope. Most of the carbon in the earth is buried deep underground, where any carbon-14 [[radioactive decay | decays]], leaving behind carbon-12. But carbon in the atmosphere (or in living creatures, which pass the carbon back and forth to the atmosphere relatively rapidly) is often struck by [[cosmic ray]]s, which can convert it from carbon-12 to carbon-14. Therefore the concentration of carbon-14 is higher in living creatures and in the atmosphere than it is in dead or buried forms of carbon.
The method is based on the fact that the carbon-12 [[isotope]] of carbon is more stable, and therefore more common, than the [[radioactivity | radioactive]] carbon-14 isotope. Most of the carbon in the earth is buried deep underground, where any carbon-14 [[radioactive decay | decays]], leaving behind carbon-12. Nitrogen-14 atoms in the stratosphere are often struck by neutrons, converting them to carbon=14 atoms. But carbon-14 in the atmosphere mixes with ordinary carbon-12 and finds it way into all living creatures. Therefore the concentration of carbon-14 is higher in living creatures and in the atmosphere than it is in dead or buried forms of carbon.
Thus, archaeologists use radiocarbon dating to measure the age of dead bodies, fossils, and burnt wood. If the concentration of carbon-14 is almost as high as in the atmosphere, then the specimen was recently alive. If it is much lower, then the specimen has been dead a long time.
Thus, archaeologists use radiocarbon dating to measure the age of dead bodies, fossils, and burnt wood. If the concentration of carbon-14 is almost as high as in the atmosphere, then the specimen was recently alive. If it is much lower, then the specimen has been dead a long time.