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.
Radiocarbon dating is a method of estimating the age of organic material.
It was developed right after World War II by Willard F.
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.
There's a small amount of radioactive carbon-14 in all living organisms.
When they die no new carbon-14 is taken in by the dead organism.
The carbon-14 it contained at the time of death decays over a long period of time.
By measuring the amount of carbon-14 left in dead organic material the approximate time since it died can be worked out.
For example, in 1991, two hikers discovered a mummified man, preserved for centuries in the ice on an alpine mountain.
Later called Ötzi the Iceman, small samples from his body were carbon dated by scientists.
The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be worked out.
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.