1. 1. What are the processes that cause the Earth’s surface to wear down? 1.Physical weathering 2.Chemical weathering 3.erosion

2. 2. What is the most frequent cause of rocks breaking apart? 1.Water freezing and thawing in rock cracks. Water expands when it freezes and enlarges the cracks. This causes the rock to eventually break apart.

3. 3. How do plants wear down rocks? 1.Roots grow into cracks and then grow larger, making the racks larger. (physical weathering)

4. 4. What is an example of oxidation? Rusty nail or rocks containing iron undergo oxidation and breakdown.

5. 5. Where does carbonic acid come from? Water and carbon dioxide combine in the air or below the earth’s surface

6. 6. What does carbonic acid do to certain kinds of rocks? Carbonic acid can dissolve some types of rocks.

7. 7. What type of rock do you suppose is most easily broken down by carbonic acid? Limestone – acid causes it to fizz

8. 8. What are lichens, and how do they break down rocks? Small crusty organisms algae and fungus Secrete a mild acid that breaks down the rocks (chemical weathering)

9. 9. What natural forces cause erosion? Water, wind, ice, and gravity

10. 10. What is mass movement? Water seeps into earth, causing land and rocks to separate and slide, resulting in landslides and rockslides.

11. 11. How and where does water cause erosion? Water can pick up and wash away rocks and earth materials, especially in places like the Grand Canyon and along coastlines. The faster the water flows or the more water = more erosion.

12. 12. How does wind cause erosion? Tiny grains of sand are picked up and carried by the wind. Sand hitting soil and rocks breaks more particles loosen.

13. 13. How does ice cause erosion? Glaciers push earth materials along as they move downhill.

14. 14. Wind blowing across bare soil moves earth material. Which size particle do you think the wind would carry farther and which would it deposit first? The smallest, lightest particles = carried farther Larger, heavier particles = deposited first when the wind slows down.

15. 15. Explain the steps in breaking down mountain rocks and depositing sand, silt and clay in different places hundreds of miles away. 1. Weathering breaks the rock into smaller and smaller pieces until they form sand, silt or clay. 2. Wind or water carry these materials. EROSION 3. Wind or water slows down, heavier particles are deposited first. Lighter particles go farther.

16. 16. If you could visit the Grand Canyon about a million years from now, what changes in the canyon would you expect to see? More erosion and weathering The Grand Canyon would probably be wider and deeper.