14 carbon dating
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.
Here’s an example using the simplest atom, hydrogen. Cosmic rays bombard Earth’s atmosphere, creating the unstable isotope carbon-14.
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.
Because the cosmic ray bombardment is fairly constant, there’s a near-constant level of carbon-14 to carbon-12 ratio in Earth’s atmosphere.
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.
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.