1. Chapter 3 Section 8 What is the rock cycle?
Objective:
Explain the rock cycle

2. Key Terms cycle: series of events that happen over and over again
rock cycle: series of natural processes by which rocks are slowly changed from one kind of rock to another kind of rock

3. Nature’s Cycles
A series of events that happen over and over again for a certain length of time is called a cycle. In nature, there are many different cycles. If you look around you, you will probably find many different examples of nature’s cycles.

4. Nature’s Cycles
The rise and fall of the ocean tides is a natural cycle that occurs twice each day. The movement of Earth around the Sun is a natural cycle that takes a year to complete. The Moon going through its phases is another cycle.

5. DEFINE:
What is a cycle?

6. The Rock Cycle
Rocks on Earth change over time. Some of the changes in rocks take place inside Earth. There, tremendous heat and pressure can slowly change rocks from one kind of rock into another. Other changes in rocks take place at the surface. On Earth’s surface, rocks may be changed by rain, ice, wind, or the action of chemicals in air or water.

7. The Rock Cycle

8. 2. INFER:
How do you think ice, rain, and wind can change rocks?

9. A Closer Look at the Rock Cycle
Look again at the diagram of the rock cycle. Notice that all three classes of rock eventually lead to sedimentary rock. The three classes of rocks can also be changed into metamorphic rocks or back into magma. However, only igneous rocks form directly from magma.

10. A Closer Look at the Rock Cycle
At Earth’s surface, rocks are broken apart by the forces of nature - moving water, ice, plant action, and wind. The particles of rock may then settle in lakes or oceans to form sediment that eventually makes up sedimentary rock.

11. A Closer Look at the Rock Cycle
Deeply buried igneous and sedimentary rocks can change into metamorphic rock or melt back into magma. Intense heat and pressure can change any rock into metamorphic rock. High temperatures can change any rock back into magma.

12. 3. OBSERVE:
How does magma become igneous rock?

13. Classwork CHECKING CONCEPTS What changes rock inside Earth?
What can all rocks be broken down into?
What kind of rock does magma cool and harden into?
What two conditions slowly change one type of rock into another?

14. Classwork THINKING CRITICALLY
5. COMPARE: How is the rock cycle like other natural cycles on Earth?
6. INFER: Why can only igneous rocks be formed directly from magma?

15. Classwork INTERPRETING VISUALS
Use figure 3-26 to answer the following questions.
7. EXPLAIN: How can igneous or metamorphic rock eventually become sedimentary rock?
8. IDENTIFY: What processes change sedimentary rock into metamorphic rock?
9. NAME: What processes or forces change metamorphic rock into igneous rock?