The technique of comparing the abundance ratio of a radioactive isotope to a reference isotope to determine the age of a material is called radioactive dating. Many isotopes have been studied, probing a wide range of time scales.

What is radioactive dating simple?

noun. any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product. Also called radioactive dating.