K-Ar dating

K-Ar (potassium-argon) dating is a method used to determine the age of rocks and minerals. It relies on measuring the amounts of potassium-40, a radioactive isotope, and argon-40, its decay product. When rocks form, they typically have little to no argon gas trapped inside. Over time, potassium-40 decays into argon-40 at a known rate. By measuring the ratio of these gases in a mineral sample, scientists can calculate how long this decay has been occurring, revealing the rock’s age—especially useful for dating volcanic rocks and minerals millions of years old.