Carbon 14

carbon 14 dating (radiocarbon dating)

Radioactive carbon 14 is a well known tool for determining the age of geological specimens and archeological artifacts. The procedure, known as carbon 14 dating or radiocarbon dating, is reasonably accurate for setting the age of objects between 500 and 50,000 years old.

Carbon-14 dating is used mainly for determining the age of objects that had once been living fossilized plants and animals, for example. A great variety of carbon compounds cycle through all living things, and some of this carbon is radioactive carbon-14.

When the creature or plant dies, the ingestion and cycling operations cease, and no fresh carbon 14 is introduced. Whatever amount of carbon 14 happens to be in the object at the time of its death begins to decay.

Decay of Carbon 14

Carbon 14 decays to nitrogen 14 at a fixed rate (half life), so the older a specimen is, the lower its concentration of carbon 14. The concentration can be measured easily with a Geiger counter.

Isotopes of Carbon

Carbon 14 is an isotope of carbon. Nearly all carbon found in nature is carbon 12. A bit over one percent is carbon 13. The remaining isotopes are radioactive and, except for carbon 14, have very short half lives.