How is radiometric dating used

10 May

Scientists discovered that rocks could be timepieces -- literally.

Many chemical elements in rock exist in a number of slightly different forms, known as isotopes.

The study of strata is called stratigraphy, and using a few basic principles, it is possible to work out the relative ages of rocks.Understanding the ages of related fossil species helps scientists piece together the evolutionary history of a group of organisms.For example, based on the primate fossil record, scientists know that living primates evolved from fossil primates and that this evolutionary history took tens of millions of years.Using this technique, called radiometric dating, scientists are able to "see" back in time.Despite seeming like a relatively stable place, the Earth's surface has changed dramatically over the past 4.6 billion years.