Follow the links below to learn more about radiocarbon dating. Radiocarbon dating uses carbon isotopes A special kind of radiocarbon dating: Bomb radiocarbon dating Although an element’s number of protons cannot change, the number of neutrons can vary slightly from each atom.
Atoms of the same element that have different numbers of neutrons are called isotopes.
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.
It can be used on objects as old as about 62,000 years.
Radiocarbon dating uses isotopes of the element carbon. This isotope lets scientists learn the ages of once-living specimens from long ago.
Organisms at the base of the food chain that photosynthesize – for example, plants and algae – use the carbon in Earth’s atmosphere.
They have the same ratio of carbon-14 to carbon-12 as the atmosphere, and this same ratio is then carried up the food chain all the way to apex predators, like sharks.
But when gas exchange is stopped, be it in a particular part of the body like in deposits on bones and teeth, or when the entire organism dies, the ratio of carbon-14 to carbon-12 begins to decrease.
Image via The Cosmic Story of Carbon-14 by Ethan Siegel, via Simon Swordy (U.Chicago), via NASA of those two isotopes in a sample.