Carbon 14 nitrogen 14 dating
Carbon has an atomic number of 6, an atomic weight of 12.011, and has three isotopes: carbon-12, carbon-13, and carbon-14.
(The numbers 12, 13 and 14 refer to the total number of protons plus neutrons in the atom's nucleus.
Stable carbon, essential to life, as we understand it, was not formed in the Big Bang or at any time during the early history of the universe.
It was created much later, after stars were formed.
Radiocarbon dating is used to work out the age of things that died up to 50,000 years ago. As far as working out the age of long-dead things goes, carbon has got a few things going for it. The proteins, carbohydrates and fats that make up much of our tissues are all based on carbon.
Everything from the fibres in the Shroud of Turin to Otzi the Iceman has had their birthday determined the carbon-14 way. There's plenty of hydrogen, oxygen and nitrogen in living things too, but carbon's got something none of them do — a radioactive isotope that can take thousands of years to decay.
And plants top up their radioactive carbon every time they turn carbon dioxide to food during photosynthesis.It help, first, to know something about carbon and where it comes from.