xxx older mature dating - How is carbon 14 used in radiocarbon dating

It's been painstakingly pieced together from the carbon content in living and long-dead tree rings. The layer (or ring) directly reflects the carbon-14 content of that year, so a ring that was formed 500 years ago tells us the ratio of carbon-14 to regular carbon-12 (14C/12C) of something that died 500 years ago.

As well as the tree ring record, scientists have used the carbon record from corals to calculate C14/C12 levels right back to 50,000 years ago.

With an extra neutron and one less proton, that's no longer a nitrogen atom — six protons plus eight neutrons spells carbon-14.

When those speedy protons hit atoms you end up with a few stray neutrons zipping around the place.

And when one of those energetic neutrons hits a nitrogen atom, the nitrogen spits out a proton.

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.

It's not that the radioactive carbon in air or food doesn't decay, it does.

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