Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.

How do scientists do absolute dating?

Most absolute dates for rocks are obtained with radiometric methods. These use radioactive minerals in rocks as geological clocks. These break down over time in a process scientists call radioactive decay. Each original isotope, called the parent, gradually decays to form a new isotope, called the daughter.

How do scientists determine the absolute ages of rocks?

The absolute age of a sample is its age in years. This method of determining absolute age is called radiometric dating, and it involves the decay, or breakdown, of radioactive elements. Using radiometric dating, scientists can determine the actual age of a rock.