Layers of Time Online Exhibit - Carbon Dating

Carbon Dating

The method of radiocarbon dating was developed from nuclear science research during World War II. Anything that contains carbon, that is—anything once living, such as wood, bone, shell, seeds—can be dated by reference to the amount of a radioactive isotope of carbon (Carbon 14) left in the object. Carbon 14 decays at a regular, known rate, so it serves as an atomic clock. Radiocarbon dates can be measured on objects more than a few hundred years old up to about 60,000 years old.

The very first radiocarbon dates were published in 1949. Archaeologists quickly seized on this method as a way to answer their most pressing question, "How old is it?"