Scientific American Editor Michael Moyer explains the process of radiocarbon dating.
is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past.
Thus, as living things take in carbon, they inevitably will take up a small amount of radioactive carbon into their bodies.
When these lifeforms die, they stop taking in new carbon.
However, scientists can look at the decay of other elements in these objects allowing them to date them up to 2.2 billion years.
Many isotopes have been studied, probing a wide range of time scales.A form of radiometric dating used to determine the age of organic remains in ancient objects, such as archaeological specimens, on the basis of the half-life of carbon-14 and a comparison between the ratio of carbon-12 to carbon-14 in a sample of the remains to the known ratio in living organisms. A technique for measuring the age of organic remains based on the rate of decay of carbon 14.The carbon 14 present in an organism at the time of its death decays at a steady rate, and so the age of the remains can be calculated from the amount of carbon 14 that is left. The cells of all living things contain carbon atoms that they take in from their environment.Back in the 1940s, the American chemist Willard Libby used this fact to determine the ages of organisms long dead.Most carbon atoms have six protons and six neutrons in their nuclei and are called carbon 12. But a tiny percentage of carbon is made of carbon 14, or radiocarbon, which has six protons and eight neutrons and is not stable: half of any sample of it decays into other atoms after 5,700 years.