Carbon dating, also referred to as radiocarbon dating or carbon-14 dating, is a method that is used to determine the age of an object.
It can only be used on objects containing organic material – that was once ‘alive’ and therefore contained carbon.
The element carbon apears in nature in a few slightly different varieties, depending on the amount of neutrons in its nucleus.
Called isotopes, these different types of carbon all behave differently.
Most of the stable, naturally occurring carbon on Earth is carbon 12 – it accounts for 99 per cent of the element on our planet.
Another carbon isotope is Carbon-14, a radioactive version of carbon.
It occurs naturally in the atmosphere as part of carbon dioxide, and animals absorb it when they breathe.
Animals stop taking it in when they die, and a finite amount of the chemical is stored in the body.
Radioactive substances all have a half-life, the length of time it takes for a material to lose half of its radioactivity.
Carbon-14 has a long half-life, 5,370 years to be exact.
This long half-life can be used to find out how old objects are by measuring how much radioactivity is left in a specimen.
Due to the long half-life, archaeologists have been able to date items up to 50,000 years old.
Radiocarbon dating was first invented in the 1940s by an American physical chemist called Willard Libby. He won the 1960 Nobel Prize in Chemistry for his discovery.