Chapter Menu

1
Chapter Menu
Chapter Introduction Lesson 1 Weathering Lesson
2 Soil Chapter Wrap-Up
2
Chapter Introduction

• What natural processes break down rocks and begin
  soil formation?

3
Chapter Introduction

• What do you think?

Before you begin, decide if you agree or disagree
with each of these statements. As you view this
presentation, see if you change your mind about
any of the statements.
4
Chapter Introduction
Do you agree or disagree?

• 1. Weathering is the same as erosion.
• 2. Humans are the main cause of weathering.
• 3. Plants can break rocks into smaller pieces.

5
Chapter Introduction
Do you agree or disagree?

• 4. Air and water are present in soil.
• 5. Soil that is 1,000 years old is young soil.
• 6. Soil is the same in all locations.

6
Lesson 1 Reading Guide - KC
Weathering

• How does weathering break down or change rock?
• How do mechanical processes break big rocks into
  smaller pieces?
• How do chemical processes change rocks?

7
Lesson 1 Reading Guide - Vocab
Weathering

• weathering
• mechanical weathering
• chemical weathering
• oxidation

8
Lesson 1-1
Weathering and Its Effects

• The mechanical and chemical processes that change
  objects on Earths surface over time are called
  weathering.
• Over thousands of years, weathering can break
  rock into smaller and smaller pieces, such as
  sand, silt, and clay.

9
Lesson 1-1
Weathering and Its Effects (cont.)
weather Science Use to change from the action of
the environment Common Use the state of the
atmosphere
10
Lesson 1-1
Weathering and Its Effects (cont.)
How does weathering break down or change rock?
11
Lesson 1-2
Mechanical Weathering

• When physical processes naturally break rocks
  into smaller pieces, mechanical weathering
  occurs.
• The chemical makeup of a rock stays the same
  during mechanical weathering.
• Mechanical weathering can be caused by ice
  wedging, abrasion, plants, and animals.

12
Lesson 1-2
13
Lesson 1-2
Mechanical Weathering (cont.)

• An example of mechanical weathering is when the
  intense heat of a forest fire causes nearby
  rocks to expand and crack.
• When something is broken into smaller pieces, it
  has a greater surface area.
• Surface area is the amount of space on the
  outside of an object.

14
Lesson 1-2
Mechanical Weathering (cont.)
What are five ways mechanical weathering breaks
large rocks into smaller pieces?
15
Lesson 1-3
Chemical Weathering

• Chemical weathering changes the materials that
  are part of a rock into new materials.
• These granite obelisks show how chemical
  weathering can affect some rock.

Dr. Marli Miller/Getty Images
16
Lesson 1-3
Chemical Weathering (cont.)

• Water is important in chemical weathering because
  most substances dissolve in water.
• The process of dissolving breaks up the minerals
  in the rock into small pieces. The small pieces
  mix with water to form a solution and are washed
  away from the rock.
• Acids are also agents of chemical weathering and
  cause more chemical weathering than pure water
  does.

17
Lesson 1-3
Chemical Weathering (cont.)

• Oxidation combines the element oxygen with other
  elements or molecules.
• The product of oxidation is called an oxide.
• When rocks that contain iron oxidize, a layer of
  iron oxide forms on the outside surface.

18
Lesson 1-3
Chemical Weathering (cont.)
How does chemical weathering change rock?
19
Lesson 1-4
What affects weathering rates?

• The environment helps determine the rate of
  weathering.
• Mechanical weathering occurs fastest in locations
  that have a lot of temperature changes.
• Chemical weathering is fastest in warm, wet
  places.
• The type of rock being weathered also affects the
  rate of weathering and determines what kinds of
  products result.

20
Lesson 1 - VS

• Weathering is the mechanical and chemical
  processes that change things over time.
• Mechanical weathering does not change the
  identity of the materials that make up rocks. It
  breaks up rocks into smaller pieces.

21
Lesson 1 - VS

• Chemical weathering is the process that changes
  the minerals that are part of every rock into
  new materials. Oxidation and reaction with an
  acid are both examples of chemical weathering.

Dr. Marli Miller/Getty Images
22
Lesson 1 LR1
The minerals that make up rock change during
which of these?
A. mechanical weathering B. chemical
weathering C. ice wedging D. abrasion
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Lesson 1 LR2
Which of these are agents of chemical weathering?
A. water B. acids C. animals D. A and B
24
Lesson 1 LR3
Which term refers to the amount of space exposed
on the outside of an object?
A. oxidation B. mechanical weathering C. surface
area D. abrasion
25
Lesson 1 - Now
Do you agree or disagree?

• 1. Weathering is the same as erosion.
• 2. Humans are the main cause of weathering.
• 3. Plants can break rocks into smaller pieces.

26
Lesson 2 Reading Guide - KC
Soil

• How is soil created?
• What are soil horizons?
• Which soil properties can be observed and
  measured?
• How are soils and soil conditions related to
  life?

27
Lesson 2 Reading Guide - Vocab
Soil

• soil
• organic matter
• pore
• decomposition
• parent material

• climate
• topography
• biota
• horizon

28
Lesson 2-1
What is soil?

• Soil is a mixture of weathered rock, decayed
  organic matter, mineral fragments, water, and
  air.
• Organic matter is the remains of something that
  was once alive.
• Decomposition is the process of changing
  once-living material into dark-colored organic
  matter.

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Lesson 2-1
What is soil? (cont.)

• Soil contains gases that fill the soil poresthe
  small holes and spaces in soil.

pore from Greek poros, means passage, way
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Lesson 2-1
What is soil? (cont.)

• The sizes of pores change with differences in
  particle size.

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Lesson 2-1
Formation of Soil

• Inorganic matter in soil is formed by the
  mechanical and chemical weathering of rocks into
  fragments.
• The term inorganic describes materials that have
  never been alive.

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Lesson 2-2
Formation of Soil (cont.)

• Parent material is the starting material of soil.
• Parent material is made of the rock or sediment
  that weathers to form the soil.

33
Lesson 2-2
Formation of Soil (cont.)
What is the role of parent material in creating
soil?
34
Lesson 2-2
Formation of Soil (cont.)

• The average weather of an area is its climate.
• If the parent material is in a warm, wet climate,
  soil formation can be rapid.
• Topography is the shape and steepness of the
  landscape.

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Lesson 2-2
Formation of Soil (cont.)

• The topography of an area determines what happens
  to water that reaches the soil surface.
• Water running downhill can carry soil with it,
  leaving some slopes bare of soil.

36
Lesson 2-2
Formation of Soil (cont.)

• Biota is all of the organisms that live in a
  region.
• Biota in the soil help speed up the process of
  soil formation in various ways.
• Organisms can be involved in decomposition of
  organic matter or form passages in soil for water
  to move through.

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Lesson 2-2

• Rock and soil are affected by organism activity.

38
Lesson 2-2
Formation of Soil (cont.)
How does biota aid in soil formation?
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Lesson 2-2

• Mature soils develop layers as new soil forms on
  top of older soil.

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Lesson 2-2
Horizons

• As time passes, weathering is constantly acting
  on rock and sediment, making soil formation a
  constant, but slow, process.
• Horizons are layers of soil formed from the
  movement of the products of weathering.

41
Lesson 2-3
Horizons (cont.)
horizon from Latin horizontem, means bounding
circle
42
Lesson 2-3
Horizons (cont.)

• Each horizon has characteristics based on the
  type of materials it contains.
• The three horizons common to most soils are
  identified as A-horizon, B-horizon, and
  C-horizon.
• The top, organic layer is called the O-horizon
  and the unweathered, bedrock layer is the
  R-horizon.

43
Lesson 2-3
Horizons (cont.)
What are soil horizons?
44
Lesson 2-4
Soil Properties and Uses
45
Lesson 2-4
Soil Properties and Uses (cont.)
46
Lesson 2-4
Soil Properties and Uses (cont.)

• Some properties of soil can be determined just by
  observation.
• The amount of sand, silt, and clay in a soil can
  be estimated by feeling the soil.
• Many soil properties can be measured more
  accurately in a laboratory.

47
Lesson 2-4
Soil Properties and Uses (cont.)

• Laboratory measurements can determine exactly
  what is in each sample of soil.

List soil properties that can be observed and
measured.
48
Lesson 2-4
Soil Properties and Uses (cont.)

• Plant growers can observe how well plants grow in
  the soil to get information about soil nutrients.

How is soil related to life?
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Lesson 2-4

• The type of soil formed depends partly on
  climate.

50
Lesson 2-5
Soil Properties and Uses (cont.)
Are soils the same everywhere?
51
Lesson 2 - VS

• The inorganic matter in soil is made up of
  weathered parent material. The organic matter in
  soil is made by the decomposition of things that
  once lived.

52
Lesson 2 - VS

• The five factors of soil formation are parent
  material, topography, climate, biota, and time.
• Soil contains horizons, which are layers formed
  from the movement of the products of weathering.
  Most soil contains A-, B-, and C-horizons.

53
Lesson 2 LR1
Which term refers to the process of changing
once-living material into dark-colored organic
matter?
A. biota B. topography C. decomposition D. mechani
cal weathering
54
Lesson 2 LR2
Which of these refers to the starting material of
soil?
A. parent material B. bed rock C. biota D. horizon
s
55
Lesson 2 LR3
Which of these is the top, organic layer of soil?
A. A-horizon B. B-horizon C. C-horizon D. O-horizo
n
56
Lesson 2 - Now
Do you agree or disagree?
4. Air and water are present in soil. 5. Soil
that is 1,000 years old is a young soil. 6. Soil
is the same in all locations.
57
Chapter Review Menu
Key Concept Summary Interactive Concept
Map Chapter Review Standardized Test Practice
58
The BIG Idea

• Physical and chemical weathering are destructive
  forces that break down rocks, which begins the
  formation of soil.

59
Key Concepts 1
Lesson 1 Weathering

• Weathering acts mechanically and chemically to
  break down rocks.
• Through the action of Earth processes such as
  freezing and thawing, mechanical weathering
  breaks rocks into smaller pieces.
• Chemical weathering by agents such as water and
  acids change the materials in rocks into new
  materials.

Dr. Marli Miller/Getty Images
60
Key Concepts 2
Lesson 2 Soil

• Five factorsparent material, climate,
  topography, biota, and timeaffect the formation
  of soil.
• Horizons are soil layers formed from the movement
  of the various products of weathering.
• Soil can be characterized by properties such as
  the amount of organic matter and inorganic
  matter.
• Plants depend on certain characteristics of soil,
  such as organic matter and amount of weathering.

61
Chapter Review MC1
Which term refers to what happens when physical
processes naturally break rocks into smaller
pieces?
A. chemical weathering B. mechanical
weathering C. oxidation D. ice wedging
62
Chapter Review MC2
What is the product of oxidation?
A. oxygen B. an oxide C. acid D. iron
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Chapter Review MC3
Where does chemical weathering occur fastest?
A. cool, dry places B. places with a lot of
temperature changes C. warm, wet places D. none
of these
64
Chapter Review MC4
Which term refers to the shape and steepness of a
landscape?
A. biota B. pores C. horizons D. topography
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Chapter Review MC5
Which of these refers to all of the organisms
that live in a region?
A. organic matter B. soil C. biota D. horizons
66
Chapter Review STP1
Which term refers to changes in the materials
that are part of a rock into new materials?
A. mechanical weathering B. abrasion C. chemical
weathering D. ice wedging
67
Chapter Review STP2
Which of these can cause mechanical weathering?
A. ice wedging B. abrasion C. plants D. all of
the above
68
Chapter Review STP3
Which of these occurs fastest in locations that
have a lot of temperature changes?
A. mechanical weathering B. oxidation C. chemical
weathering D. none of these
69
Chapter Review STP4
Which term refers to the small holes and spaces
in soil?
A. biota B. pores C. horizons D. silt
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Chapter Review STP5
Why will weathering occur more quickly to a rock
that has been broken into several pieces?
A. The surface area of the broken pieces is
larger. B. The surface area of the broken pieces
is smaller. C. The total weight of the rock
decreases when it is broken. D. The total weight
of the rock increases when it is broken.