Name: _____________________________
8th Grade Science
Date: ____________
Period: _____
Mr. Vorstadt
Weathering and Erosion
You can understand weathering and erosion as dynamic forces that have cumulative,
long-term effects on the solid surface of Earth.
Weathering = is the process during which rocks are broken into sediments.
Sediments = are small pieces of weathered rock moved by gravity, wind, rain, or ice.
Soil = is a mixture of sediment, organic material, air. and water.
Erosion = is the movement of sediment due to gravity, water, wind, and ice.
Glaciers = are large "rivers" of ice that move slowly downhill and remain frozen
all year long.
DIRECTIONS Read the following information.
It is easy to notice the changes weather has on Earth's surface. Heavy rains can
wash away soil and strong wind can blow sand into high sand dunes. Other changes are
very small, but add up over long periods of time. For example, solid rock may be broken
down into sediment over many years by the processes of weathering. Heating and cooling
of rocks can make them crack. These cracks may fill with water. When the water freezes, it
expands, widening the crack. Plant roots may grow into cracks, forcing them even wider.
Some minerals in rock may dissolve over time. Wind and precipitation may also wear away
solid rock.
All these processes break rock into small pieces called sediments. Sediment
provides the mineral content of soil. Soil is a mixture of sediment, organic material, water,
and air. Soil formation could not occur without the sediment from weathered rocks.
GUIDED QUESTIONS
What are some processes that produce weathering? _______________________________
_________________________________________________________________________
What are sediments? _______________________________________________________
What are the components of soil? ______________________________________________
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Erosion is the transport of sediment. Gravity is the driving force behind erosion.
Gravity may act directly, causing loose objects to slip down a slope. This type of
movement may be fast, as in a mudslide or landslide. Gravity may also act indirectly,
through moving water or glaciers. Winds and rivers can pick up loose sediments and carry
them along. These loose sediments in rivers can scrape away at surfaces and
over millions of years carve out deep canyons.
Glaciers also flow downhill, though very slowly. Glaciers are large "rivers" of ice that
move slowly down a valley, exerting tremendous force on the rock
below. Although slow, glaciers can scrape away rock layers and move huge amounts of
materials over long.
GUIDED QUESTIONS
What is the force behind erosion? _____________________________________________
What is a glacier? __________________________________________________________
Directions For each question, write your answer in the spaces provided.
1. What is the difference between weathering and erosion?
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2. How does gravity act directly to cause erosion?
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3. How does gravity act indirectly to cause erosion?
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4. Describe glaciers and how they cause erosion.
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5. How is moving water or wind able to erode a surface more quickly than still
water or air?
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_______________________________________________________________
6. Over time, rocky mountain peaks are weathered and eroded away. What types
of weathering and erosion could occur?
___________________________________________________________________
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Directions (7-11): For each question, write your answer in the spaces
provided. Base your answers to questions 7 through 11 the paragraph
and table below.
Without weathering, rock would not be broken down into smaller pieces, and soil
formation could not begin. Wind, rain, and freezing water all help break down rock.
Earth's moon has plenty of rocks. It also has no atmosphere or weather, and soil that
consists only of broken rocks and dust.
COMPONENTS OF SOIL
Components
Sediment
Humus
Air
Water
Description
fragments of sand, silt, clay, and other minerals from weathered rock
decaying organic matter such as leaves; loosen soil and makes it less dense
and more fertile
gases in spaces between sediments and humus
moisture present in soil; can hold more water, dry soil has little or no water
present
7. What begins soil formation?
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8. What components of soil on Earth would not be in the Moon's "soil"? Explain
your answer.
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9. Why is humus an important part of fertile soil?
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10. What types of sediment are in soils? Which is most common in desert soils?
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11. Burrowing insects and animals often live in soil. How do they speed erosion?
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Directions (12-19): Each question is followed by four choices. Decide which choice is the
best answer. Write the number of the answer you have chosen on the line provided.
_____ 12. Solid rock may be broken down by a process called
(1) weathering (2) erosion (3) soil
(4) gravity
_____ 13. The driving force behind erosion is
(1) water
(2) sunlight (3) magnetism
(4) gravity
_____ 14. A mass of ice moving slowly downhill, causing erosion, is called a
(1) river (2) icicle (3) iceberg (4) glacier
_____ 15. Which process involves the transport of sediment?
(1) weathering (2) erosion (3) freezing (4) thawing
_____ 16. One result of weathering is the creation of
(1) humus (2) rivers (3) mountains
(4) sediments
_____ 17. Which of these terms includes the other three?
(1) soil
(2) humus (3) water (4) sediment
_____ 18. Which is the organic part of soil?
(1) sediment (2) water (3) humus
(4) air
_____ 19. The Moon is made up of rocks and dust-like soil. Which is the likely cause of
"soil" on the Moon?
(1) weathering by glaciers
(2) weathering by wind
(3) breakup of rock by moving water
(4) breakup of rock when meteors struck the Moon
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