1. Chapter 10 Table of Contents Section 1 Weathering
Weathering and Soil Formation
Table of Contents
Section 1 Weathering
Section 2 Rates of Weathering
Section 3 From Bedrock to Soil
Section 4 Soil Conservation

2. Chapter 10
Section 1 Weathering
Bellringer
Think about how potholes form in paved roads. Write a few sentences that describe how water contributes to the formation of potholes. Illustrate how cycles of freezing and thawing help cause potholes to grow.
Record your response in your science journal.

3. Chapter 10
Section 1 Weathering
Objectives
Describe how ice, water, wind, gravity, plants, and animals cause mechanical weathering.
Describe how water, acids, and air cause chemical weathering of rocks.

4. Mechanical Weathering
Chapter 10
Section 1 Weathering
Mechanical Weathering
Ice The alternate freezing and thawing of soil and rock, called frost action, is a form of mechanical weathering.
Abrasion Abrasion is the grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles.
Wind, Water, and Gravity Wind, water, and gravity carry rocks, causing them to abrade against one another.

5. Ice Wedging Chapter 10 Section 1 Weathering
Click below to watch the Visual Concept.
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Visual Concept

6. Mechanical Weathering, continued
Chapter 10
Section 1 Weathering
Mechanical Weathering, continued
Plants As a plant grows, the force of the expanding root becomes so strong that it can break a rock apart.
Animals Almost any animal that burrows causes mechanical weathering by mixing and digging through soil and rock particles.

7. Animals and Mechanical Weathering
Chapter 10
Section 1 Weathering
Animals and Mechanical Weathering
Animals that burrow in the ground break up soil and loosen rocks to be exposed to further weathering.

8. Chemical Weathering Chapter 10
Section 1 Weathering
Chemical Weathering
Water Even hard rock, such as granite, can be broken down by water. The next slide shows how this can happen.
Acid Precipitation The high level of acidity in acid precipitation can cause very rapid weathering of rock.
Acids in Groundwater When acidic groundwater comes into contact with limestone, the limestone is dissolved and forms karst features.

9. Chapter 10
Section 1 Weathering

10. Chemical Weathering, continued
Chapter 10
Section 1 Weathering
Chemical Weathering, continued
Acids in Living Things Some living things, such as lichens, produce acids that can slowly break down rocks.
Air Oxygen in the air causes oxidation. Oxidation is the chemical reaction in which an element, such as iron, combines with oxygen to form an oxide.

11. Oxidation Chapter 10 Section 1 Weathering
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Visual Concept

12. Chapter 10
Section 2 Rates of Weathering
Bellringer
Imagine that you are in a sand castle-building competition at the beach. Come up with ways to protect your castle against the weathering effects of the wind and waves.
Record your response in your science journal.

13. Chapter 10
Section 2 Rates of Weathering
Objectives
Explain how the composition of rock affects the rate of weathering.
Describe how a rock’s total surface area affects the rate at which the rock weathers.
Describe how differences in elevation and climate affect the rate of weathering.

14. Differential Weathering
Chapter 10
Section 2 Rates of Weathering
Differential Weathering
What Is Differential Weathering? Differential weathering is a process by which softer, less weather resistant rock wear away and leave harder, more weather resistant rock. The image below is an example of differential weathering.

15. The Shape of Rocks Chapter 10
Section 2 Rates of Weathering
The Shape of Rocks
Surface Area The more surface area of a rock that is exposed to weathering, the faster the rock will be worn down.
Increasing the Rate of Weathering If a large rock is broken down into smaller fragments, weathering of the rock happens much more quickly.

16. Chapter 10
Section 2 Rates of Weathering

17. Weathering and Climate
Chapter 10
Section 2 Rates of Weathering
Weathering and Climate
What Is Climate? Climate is the average weather condition in an area over a long period of time.
Temperature and Water The rate of chemical weathering happens faster in warm, humid climates. Water also increases the rate of mechanical weathering.

18. Weathering and Elevation
Chapter 10
Section 2 Rates of Weathering
Weathering and Elevation
High Elevations Rocks at higher elevations, as on a mountain, are exposed to more wind, rain, and ice than rocks at lower elevations.
Steep Slopes The steepness of mountain slopes increases the effects of mechanical and chemical weathering. Steep slopes cause water and sediments to quickly run down the side of the mountain.

19. Bellringer Chapter 10 Answer the following questions:
Section 3 From Bedrock to Soil
Bellringer
Answer the following questions:
Has there always been soil on Earth?
What makes soil valuable to humans?
Write your answers in your science journal.

20. Objectives Chapter 10 Describe the source of soil.
Section 3 From Bedrock to Soil
Objectives
Describe the source of soil.
Explain how the different properties of soil affect plant growth.
Describe how various climates affect soil.

21. The Source of Soil Chapter 10
Section 3 From Bedrock to Soil
The Source of Soil
What Is Soil? Soil is a loose mixture of small mineral fragments, organic material, water, and air that can support the growth of vegetation.
Residual and Transported Soil Soil that remains above its parent rock is called residual soil. Soil that is blown or washed away from its parent rock is called transported soil.

22. Residual and Transported Soil
Chapter 10
Section 3 From Bedrock to Soil
Residual and Transported Soil
Click below to watch the Visual Concept.
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Visual Concept

23. Soil Properties Chapter 10
Section 3 From Bedrock to Soil
Soil Properties
Soil Texture and Soil Structure Soil texture is the soil quality that is based on the proportions of soil particles. Soil structure is the arrangement of soil particles.

24. Chapter 10
Section 3 From Bedrock to Soil

25. Soil Properties, continued
Chapter 10
Section 3 From Bedrock to Soil
Soil Properties, continued
Soil Fertility A soil’s ability to hold nutrients and to supply nutrients to a plant is described as soil fertility.
Soil Horizons Because of the way soil forms, soil often ends up in a series of layers called horizons.
Soil pH Soils can be acidic or basic. The pH scale is used to measure how acidic or basic a soil is.

26. Leaching Chapter 10 Section 3 From Bedrock to Soil
Click below to watch the Visual Concept.
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Visual Concept

27. Soil and Climate Chapter 10
Section 3 From Bedrock to Soil
Soil and Climate
Tropical Rain Forest Climates The warm soil in tropical rain forest climates allows dead plants and animals to decay easily. This provides rich humus to the soil.
Desert Climates The lack of rain in desert climates leads to low rates of chemical and mechanical weathering.

28. Soil and Climate, continued
Chapter 10
Section 3 From Bedrock to Soil
Soil and Climate, continued
Temperate Forest and Grassland Climates Temperate forest and grassland climates get enough rain to cause a high level of chemical weathering, but not too much that nutrients are leached out.
Arctic Climates In arctic climates, as in desert climates, chemical weathering occurs very slowly. Low temperatures slow the formation of humus.

29. Chapter 10
Section 4 Soil Conservation
Bellringer
Franklin D. Roosevelt once said: “The nation that destroys its soil destroys itself.”
What do you think this quote means? Record your response in your science journal.

30. Chapter 10
Section 4 Soil Conservation
Objectives
Describe three important benefits that soil provides.
Describe four methods of preventing soil damage and loss.

31. The Importance of Soil Chapter 10
Section 4 Soil Conservation
The Importance of Soil
Nutrients Soil provides minerals and other nutrients for plants. All animals get their energy from plants.
Housing Soil provides a place for animals to live.
Water Storage Without soil to hold water, plants would not get the moisture or the nutrients they need.

32. Soil Damage and Loss Chapter 10
Section 4 Soil Conservation
Soil Damage and Loss
Overuse Overused soil can lose its nutrients and become infertile.
Soil Erosion When soil is left unprotected, it can be exposed to erosion. Erosion is the process by which wind, water, or gravity transport soil and sediment from one location to another.

33. Contour Plowing and Terracing
Chapter 10
Section 4 Soil Conservation
Contour Plowing and Terracing
Contour Plowing In contour plowing, the rows of soil act as a series of dams to prevent water from eroding topsoil away.
Terracing If hills are steep, farmers can using terracing. Terracing changes one steep field into a series of smaller, flatter fields.

34. Cover Crop and Crop Rotation
Chapter 10
Section 4 Soil Conservation
Cover Crop and Crop Rotation
Cover Crops Cover crops are crops that are planted between harvests to replace certain nutrients and prevent erosion. Cover crops prevent erosion by providing cover from wind and rain.
Crop Rotation Farmers can rotate crops that use different nutrients so that nutrients in the soil have time to become replenished.

35. Chapter 10
Weathering and Soil Formation
Concept Map
Use the terms below to complete the concept map on the next slide.
parent rock
chemical weathering
mechanical weathering
rock
ice wedging
oxidation
soil

36. Chapter 10
Weathering and Soil Formation

37. Chapter 10
Weathering and Soil Formation

38. End of Chapter 10