History & CultureHow it works
How archaeologists tell a bone's age.
Living things constantly take in the radioactive carbon isotope C-14. At death the supply stops, and C-14 decays with a half-life of 5,730 years. Measure how much is left in wood, bone or cloth and you know when it died, back to about 50,000 years. Willard Libby developed the method in 1949 and won the 1960 Chemistry Nobel for it.
Useful: It doesn't work on stone tools: only things that were once alive can be dated this way.
Source: en.wikipedia.org