1. Weathering and Soil
Test Review

2. Question 1
True or False: After chemical weathering, the chemical make up of the rock is the same.
False

3. Question 2 Which soil layer contains partially weathered rock?
C Horizon

4. Question 3
What is the loose material on the Earth’s surface that contains humus?
Soil

5. Question 4 Which soil layer is the best for growing plants?
The A Horizon (Topsoil)

6. Question 5
What agent of mechanical weathering wears away rock by the grinding action of other rock particles?
Abrasion

7. Question 6 How does ice wedging cause mechanical weathering of rocks?
By freezing and thawing

8. Question 7
The growth of plant roots and animal activity is what type of weathering?
Mechanical Weathering

9. Question 8
What kind of weathering causes the mineral composition of rocks to change?
Chemical weathering

10. Question 9
A rock containing iron becomes soft and crumbly and reddish-brown in color. It has probably been weathered by what?
Oxygen (oxidation)

11. Question 10
How does a hot and wet climate affect the rate of weathering?
It makes it take place faster

12. Question 11
What are the most important factors in determining the weathering rate of rocks?
Climate and mineral composition

13. Question 12 Why do permeable rocks weather easily?
Because they are full of tiny connected air spaces

14. Question 13
How does soil formation begin?
With the weathering of rock

15. Question 14
What is the mixture of rock particles, minerals, decayed organic material, water, and air called?
Soil

16. Question 15
What is the decayed organic material in soil called?
Humus

17. Question 16
Removing nutrients such as iron and copper from the ground is called what?
Depletion

18. Question 17
Which soil particle is the largest?
Gravel

19. Question 18
What soil particle is the smallest?
Clay

20. Question 19 The type of soil called loam is made of what?
Nearly equal amounts of sand, silt, and clay

21. Question 20
In which layer of soil is topsoil found?
A Horizon

22. Question 21 What type of particles does the B Horizon contain?
Clay, minerals, and a little humus

23. Question 22 What do living organisms do in the soil?
Mix the soil and make humus

24. Question 23 What do decomposers do in soil?
Break down and digest the remains of dead organisms

25. Question 24
Which organism does most of the work of mixing humus into the soil?
Earthworms

26. Question 25
What can cause the loss of soil that is not protected by plant cover?
Erosion by wind or water

27. Question 26
Plowing removed the grass from the Great Plains and exposed the soil. What effect did this have when a drought struck the Great Plains during the 1930’s?
It helped to cause the Dust Bowl

28. Question 27 Using land to grow food crops is an example of what?
Agriculture

29. Question 28 What is the solid layer of rock beneath the soil called?
The Bedrock (R Horizon)

30. Question 29
What is another name for the B Horizon?
Subsoil

31. Question 30
What type of weathering occurs when pollutants in the air mix with the water vapor in the air?
Acid Precipitation