Carbon-14 Dating

	Carbon-14 dating is important in archeology. Archeologists use counts of the radioactive isotope C-14 to date organic remains such as wood, bone, and charcoal. It's usable in the range of about 50,000 years to the present.

	Here's why it works: Living animals (and people!) absorb all the isotopes of carbon. They absorb the unstable isotope Carbon-14, as well as the stable isotopes C-13 and C-12. Carbon-14 decays into N-14 continuously. After an organism's death, C-14 continues to decay but no new C-14 is added. So measuring the amount of C-14 left tells you how long ago the organism lived and died.

	Since the half-life of C-14 is relatively short, ancient remains have very little C-14. Carbon-14 dating isn't so useful for geologists and paleontologists, because the objects they're interested in are usually much, much older than 50,000 years. Dating with other radioisotopes is very useful for geologists and paleontologists.