By measuring the ratio of carbon-12 to carbon-14 in the sample and comparing it to the ratio in a living organism, it is possible to determine the age of the artifact.If you're seeing this message, it means we're having trouble loading external resources on our website.Carbon-14, or radiocarbon, is a naturally occurring radioactive isotope that forms when cosmic rays in the upper atmosphere strike nitrogen molecules, which then oxidize to become carbon dioxide.
Love-hungry teenagers and archaeologists agree: dating is hard.
But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.
Until this century, relative dating was the only technique for identifying the age of a truly ancient object.
By examining the object's relation to layers of deposits in the area, and by comparing the object to others found at the site, archaeologists can estimate when the object arrived at the site.
Libby and coworkers, and it has provided a way to determine the ages of different materials in archeology, geology, geophysics, and other branches of science.
Some examples of the types of material that radiocarbon can determine the ages of are wood, charcoal, marine and freshwater shell, bone and antler, and peat and organic-bearing sediments.
Carbon-14 has a half-life of 5,730 ± 40 years, meaning that every 5,700 years or so the object loses half its carbon-14.
Samples from the past 70,000 years made of wood, charcoal, peat, bone, antler or one of many other carbonates may be dated using this technique.
Both Carbon-12 and Carbon-13 are stable, but Carbon-14 decays by very weak beta decay to nitrogen-14 with a half-life of approximately 5,730 years.
After the organism dies it stops taking in new carbon.
As you learned in the previous page, carbon dating uses the half-life of Carbon-14 to find the approximate age of certain objects that are 40,000 years old or younger.