Download 12.4 - Answer Key - Directed Reading A

Skills Worksheet
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Directed Reading A – 12.4 – Answer Key
Section: The Effect of Gravity on Erosion and Deposition
1. What is mass movement?
Mass movement is the movement of any material, such as rock, soil, or snow
downslope.
2. What causes ice, rocks, and soil to move down a slope?
Gravity causes ice, rock, and soil to move down a slope.
ANGLE OF REPOSE
3. What is the “angle of repose”?
The angle of repose is the steepest angle or slope at which loose material will not
slide downslope.
4. What are three of the characteristics of a material that will affect its angle of
repose?
The of the characteristics of a material that affect the angle of repose are size,
weight, shape, and moisture level.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
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Agents of Erosion and Deposition
Directed Reading A continued
RAPID MASS MOVEMENT
Match the correct definition with the correct term. Write the letter in the space
provided. Some terms will not be used.
E____ 5. a group of loose rocks falling down a
steep slope
A____ 6. sudden, rapid movement of rock and soil
down a slope
D____ 7. mudflows of volcanic origin
a.
b.
c.
d.
e.
f.
landslide
slump
mudflow
lahar
rock fall
monsoon
C____ 8. rapid movement of a large mass of mud
SLOW MASS MOVEMENT
C____ 9. Extremely slow movement of material downhill is called
a. slump.
b. rock fall.
c. creep.
d. mudflow.
10. What are three factors that affect creep?
Three factors that affect creep are water, plant roots, and animals.
Water loosens soil and allows it to move.
Plant roots wedge rocks and soil apart.
Burrowing animals loosen rock and soil.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Science and Technology
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Agents of Erosion and Deposition