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.
So, if you were asked to find out carbon's half-life value (the time it takes to decrease to half of its original size), you'd solve for t number of years when in any remains will have broken down.
This process, known as carbon dating, was developed by the American chemist Willard Libby in 1947 at the Institute for Nuclear Studies at Columbia University.
Carbon dating uses an exponential decay function, remaining in an object that is t years old.
This resemblance is used in chemical and biological research, in a technique called carbon labeling: carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound.
These are relatively low energies; the maximum distance traveled is estimated to be 22 cm in air and 0.27 mm in body tissue.