Carbon dating a fossil
Carbon is naturally in all living organisms and is replenished in the tissues by eating other organisms or by breathing air that contains carbon.At any particular time all living organisms have approximately the same ratio of carbon 12 to carbon 14 in their tissues.
In the case of radiocarbon dating, the half-life of carbon 14 is 5,730 years.
This half life is a relatively small number, which means that carbon 14 dating is not particularly helpful for very recent deaths and deaths more than 50,000 years ago.
Love-hungry teenagers and archaeologists agree: dating is hard.
But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.
As scrolls, plant-based paints or cotton shirts age over thousands of years, the radioactive carbon-14 that naturally appears in organic objects gradually decays.