CHAPTER
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Weathering and Soil Formation
the BIG idea
Natural forces break rocks apart and form soil, which supports life.
4.1 Mechanical and chemical forces break down rocks.
4.2 Weathering and organic processes form soil.
4.3 Human activities affect soil.
CHAPTER OUTLINE
CHAPTER RESOURCES
4.1
CHAPTER HOME
KEY CONCEPT
Mechanical and chemical forces break down
rocks.
VOCABULARY
weathering
mechanical
weathering
Over time,
mechanical
weathering
breaks a
rock into
smaller
pieces.
exfoliation
abrasion
chemical weathering
CHAPTER
RESOURCES
SECTION
OUTLINE
4.1
CHAPTER HOME
KEY CONCEPT
Mechanical and chemical forces break down
rocks.
VOCABULARY
weathering
mechanical
weathering
exfoliation
Chemical
weathering
affects exposed
rock surfaces
VISUALIZATION
CLASSZONE.COM
Watch chemical weathering in
action.
abrasion
chemical weathering
CHAPTER
RESOURCES
SECTION
OUTLINE
4.2
CHAPTER HOME
KEY CONCEPT
Weathering and organic processes form soil.
VOCABULARY
Soil has measurable properties, such as color,
texture, pore space, and chemistry.
humus
soil horizon
soil profile
Soil is a mixture
of weathered
rock, organic
matter, water,
and air.
Plants, microorganisms,
and animals affect soil
characteristics.
CHAPTER
RESOURCES
SECTION
OUTLINE
4.2
KEY CONCEPT
CHAPTER HOME
Weathering and organic processes form soil.
VOCABULARY
Soil has measurable properties, such as color,
texture, pore space, and chemistry.
humus
soil horizon
soil profile
VISUALIZATION
Learn how materials break
down and contribute to soil
buildup over time.
CHAPTER
RESOURCES
SECTION
OUTLINE
4.3
KEY CONCEPT
CHAPTER HOME
Human activities affect soil.
Soil is essential to life and takes a long time to form. It is
difficult or impossible to replace soil that has been lost.
VOCABULARY
desertification
Soil Loss
Farming, construction
and development, and
mining are three human
activities that affect soil.
CHAPTER
RESOURCES
SECTION
OUTLINE
4.3
CHAPTER HOME
KEY CONCEPT
Human activities affect soil.
Soil is essential to life and takes a long time to form. It is
difficult or impossible to replace soil that has been lost.
VOCABULARY
desertification
Soil Conservation
Soil conservation
practices help keep
soil from blowing or
washing away.
CHAPTER
RESOURCES
SECTION
OUTLINE
4.1
KEY CONCEPT
CHAPTER HOME
Mechanical and chemical forces break down
rocks.
I. Mechanical and chemical forces break down rocks.
A. Weathering breaks rocks into smaller pieces.
B. Mechanical weathering produces physical
changes in rocks.
C. Chemical weathering changes the mineral
composition of rocks.
VOCABULARY
weathering
mechanical
weathering
exfoliation
abrasion
chemical weathering
1. Dissolving
2. Rusting
D. Weathering occurs at different rates.
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY
4.2
KEY CONCEPT
CHAPTER HOME
Weathering and organic processes form soil.
II. Weathering and organic processes form soil.
A. Soil is a mixture of weathered rock particles
and other materials.
1. Soil Composition
2. Soil Horizons
VOCABULARY
humus
soil horizon
soil profile
B. Climate and landforms affect soil.
C. The activities of organisms affect soil.
D. Properties of soil can be observed and
measured.
1. Texture
2. Color
3. Pore Space
4. Chemistry
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY
4.3
KEY CONCEPT
CHAPTER HOME
Human activities affect soil.
III. Human activities affect soil.
VOCABULARY
desertification
A. Soil is a necessary resource.
B. Land-use practices can harm soil.
1. Farming
2. Construction and Development
3. Mining
C. Soil can be protected and conserved.
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY
CHAPTER HOME
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