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The Rock Cycle

The Rock Cycle

Introduction: Geologists classify rocks based on how they form. There are three rock types: igneous, metamorphic, and sedimentary. Igneous rocks form when magma or lava cools and hardens into rock. This is the process of solidification. Metamorphic rocks form when heat and pressure change rocks. Mountain building, burial, and faulting are a few ways rocks undergo metamorphism, or change into metamorphic rocks. Sedimentary rocks can form when rocks break apart, move, then settle and harden. These are the processes of weathering, erosion, deposition and cementation.

But, rocks don't just form once! The Earth is always changing. Convection currents deep within the mantle move tectonic plates. Water, wind, ice and gravity work on the Earth's surface to break down and move rocks. Magma cools within the Earth's interior and erupts as lava on its surface. All of these processes change rocks. Over thousands and even millions of years, rocks change from one type to other. This process of changing rocks into different types is the rock cycle. The diagram illustrates the steps of the rock cycle.
Rock Cycle Diagram With Text Labels

Directions for This Lesson: In this lesson, you will learn about the rock cycle. First, try the practice questions to determine what you already know. Then, watch the video lesson to learn more. Finally, apply what you learned in the activity and practice sections.


Required Video:

View this interactive animation to visualize the rock cycle.

Practice what you have learned by completing the post-lesson worksheet.