Absolute and relative dating methods.

Absolute and relative dating are the two basic methods used to date rocks and arrange geological events in sequential order. Absolute dating determines the actual age of rocks while relative dating uses rocks and fossils to put geological events in a sequence. Scientists often use radiometric methods for absolute dating. These methods involve measuring radioactive elements and their isotopes, which are found in rocks. After measuring the isotopes, a scientist can use the known half-life of the isotopes to determine the actual age of a rock. In relative dating, scientists use the fundamental principles of stratigraphy, as well as a process called correlation, to determine a sequence of geological events. Scientists often make correlations between rocks and fossils in different locations to determine the succession of events.