Radiometric dating (often called radioactive dating) is a way to find out how old something is.
Radiometric dating is also used to date archaeological materials, including ancient artifacts.
Radiometric dating methods are used to establish the geological time scale.
All ordinary matter is made up of combinations of chemical elements, each with its own atomic number, indicating the number of protons in the atomic nucleus.
Elements exist in different isotopes, with each isotope of an element differing in the number of neutrons in the nucleus.
A particular isotope of a particular element is called a nuclide. That is, at some point in time, an atom of such a nuclide will spontaneously change into a different nuclide by radioactive decay.
The decay may happen by emission of particles (usually electrons (beta decay), positrons or alpha particles) or by spontaneous nuclear fission, and electron capture.Plotting an isochron (straight-line graph) is used to solve the age equation graphically.It shows the age of the sample, and the original composition.The method works best if neither the parent nuclide nor the daughter product enters or leaves the material after its formation.Anything which changes the relative amounts of the two isotopes (original and daughter) must be noted, and avoided if possible.Contamination from outside, or the loss of isotopes at any time from the rock's original formation, would change the result.