Clocks In Rocks Today, scientists use a variety of techniques to date rocks and fossils precisely. Most often, they measure the amounts of particular radioactive elements—often radiocarbon or potassium—present to determine when a rock was formed, or when an animal or plant died.

How do scientists use radiometric dating to date rocks fossils and artifacts?

While radiocarbon dating is useful only for materials that were once alive, scientists can use uranium-thorium-lead dating to measure the age of objects such as rocks. In this method, scientists measure the quantity of a variety of different radioactive isotopes, all of which decay into stable forms of lead.