The Rock Cycle

Sugarloaf Rock in Western Australia

Each day, materials are recycled by consumers so that they can be remade into another form. The rocks on Earth go through a similar process. Scientists believe that the Earth is 4.65 billion years old, and that it is not gaining in size. Earth stays approximately the same size and is made of the same matter as it was billions of years ago. The rocks of Earth have a variety of ages ranging from a few days to a few billion years old. The reason for the varying age of rocks is due to the rock cycle. The rocks of Earth are constantly forming and reforming through certain processes. In this topic, you will review the three rock types and investigate how the three rock types form and change.

Essential Question

• What is the rock cycle, and how does it work?