1. Rocks and The Rock Cycle

2. Rocks All rocks are mixtures of minerals.
Scientists classify rocks according to how they are formed.
There are three types of rocks:
Igneous
Sedimentary
Metamorphic

3. Igneous Rocks Igneous rocks form from cooled magma or lava.
When magma or lava cools it hardens to form a rock.
Magma is melted rock below Earth’s surface.
Lava is melted rock that flows out of the ground onto Earth’s surface.

4. Igneous Rocks and Crystals
Igneous rocks may have small or large crystals.
If the rock is made from magma it may have large crystals because it cools slowly.
If the rock is made from lava it may have small crystals because it cools faster.

5. Igneous Rocks
Volcano

6. Examples of Igneous Rocks
Obsidian
Granite

7. Sedimentary Rocks Sedimentary rocks are made of sediments.
Sediments are bits of rocks, shells, and the remains of dead plants and animals.
Over millions of years sediments that are buried under ground are pressed and cemented together to form a sedimentary rock.

9. Sedimentary Rocks and Fossils
Fossils are often found in Sedimentary rocks.

10. Layers of Sedimentary Rocks
Sedimentary rocks often form in layers.
The oldest layer is on the bottom.
The youngest layer is on the top.

11. Oldest or Youngest?
Youngest
Oldest

12. Examples of Sedimentary Rocks
Limestone
Shale

13. Metamorphic Rocks
Metamorphic rocks are formed from existing rocks that have been squeezed and heated deep inside Earth’s crust.

14. Examples of Metamorphic Rocks
Gneiss
Marble

15. The Rock Cycle
The rock cycle is the process of rocks changing into other kinds of rock.

16. Factors of The Rock Cycle
Melting
Cooling and Hardening
Weathering and Erosion
Squeezing and Cementing
Heating

17. The Rock Cycle

18. Questions

19. What are some factors that affect the rock cycle?

20. Are rocks always changing?

21. Which type of rock has layers?

22. Which layer is the oldest? Bottom or Top

23. How are rocks formed? Igneous- Sedimentary- Metamorphic-