Science Common Sense

82 - How do scientists determine the age of rocks?

Scientists determine the age of rocks using different methods, including:

1. Fossil method: If a rock has fossils of plants or animals that lived a long time ago, scientists can find out how old those plants or animals were and match that to the age of the rock.

2. Radioactive dating: Some rocks have tiny amounts of radioactive elements like Uranium or Potassium. These elements break down into different elements at a known rate. By measuring how much of the original element is left, scientists can figure out how old the rock is.

3. Geologic time scale: Scientists have created a big timeline of Earth's history, with layers of rock matching different time periods. If a rock is in a layer that's known to be a certain age, then the rock is likely the same age as the layer.

These methods help scientists figure out how old rocks are and what happened on Earth in the past.