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1. How to Use This Presentation • To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” • To advance through the presentation, click the right-arrow key or the space bar. • From the resources slide, click on any resource to see a presentation for that resource. • From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. • You may exit the slide show at any time by pressing the Esc key.

2. Resources Bellringers Chapter Presentation Transparencies Standardized Test Prep Image and Math Focus Bank CNN Videos Visual Concepts

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

4. Chapter 10 Section 1Weathering 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.

5. Chapter 10 Section1 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.

6. Chapter 10 Section1 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.

7. Chapter 10 Section1 Weathering Ice Wedging Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

8. Chapter 10 Section1 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.

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

10. Chapter 10 Section1 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.

11. Chapter 10 Section1 Weathering

12. Chapter 10 Section1 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.

13. Chapter 10 Section1 Weathering Oxidation Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

14. Chapter 10 Section 2Rates 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.

15. Chapter 10 Section2 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.

16. Chapter 10 Section2 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.

17. Chapter 10 Section2 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.

18. Chapter 10 Section2 Rates of Weathering

19. Chapter 10 Section2 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.

20. Chapter 10 Section2 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.

21. Chapter 10 Section 3From 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.

22. Chapter 10 Section3 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.

23. Chapter 10 Section3 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.

24. Chapter 10 Section3 From Bedrock to Soil Residual and Transported Soil Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

25. Chapter 10 Section3 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.

26. Chapter 10 Section3 From Bedrock to Soil

27. Chapter 10 Section3 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.

28. Chapter 10 Section3 From Bedrock to Soil Leaching Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

29. Chapter 10 Section3 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.

30. Chapter 10 Section3 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.

31. Chapter 10 Section 4Soil 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.

32. Chapter 10 Section4 Soil Conservation Objectives • Describe three important benefits that soil provides. • Describe four methods of preventing soil damage and loss.

33. Chapter 10 Section4 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.

34. Chapter 10 Section4 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.

35. Chapter 10 Section4 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.

36. Chapter 10 Section4 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.

37. Chapter 10 Weathering and Soil Formation Concept Map Use the terms below to complete the concept map on the next slide.

38. Chapter 10 Weathering and Soil Formation

39. Chapter 10 Weathering and Soil Formation

40. End of Chapter 10 Show

41. Standardized Test Preparation Chapter 10 Reading Read each of the passages. Then, answer the questions that follow each passage.

42. Standardized Test Preparation Chapter 10 Passage 1Earthworms are very important for forming soil. As they search for food by digging tunnels in the soil, they expose rocks and minerals to the effects of weathering. Over time, this process makes new soil. And as the worms dig tunnels, they mix the soil, which allows air and water and smaller organisms to move deeper into the soil. Worms have huge appetites. They eat organic matter and other materials in the soil. One earthworm can eat an amount equal to about half its body weight each day! Continued on the next slide

43. Standardized Test Preparation Chapter 10 Passage 1, continuedEating all of that food means that earthworms leave behind a lot of waste. Earthworm wastes, called castings, are very high in nutrients and make excellent natural fertilizer. Castings enrich the soil and enhance plant growth.

44. Standardized Test Preparation Chapter 10 1. In the passage, what does enhance mean? Ato weaken Bto improve Cto smooth out Dto decrease

45. Standardized Test Preparation Chapter 10 1. In the passage, what does enhance mean? Ato weaken Bto improve Cto smooth out Dto decrease

46. Standardized Test Preparation Chapter 10 2. According to the passage, the earthworms Feat organic matter and other materials in soil. Gdo not have much of an appetite. Hlove to eat castings. Icannot digest organic matter in soil.

47. Standardized Test Preparation Chapter 10 2. According to the passage, the earthworms Feat organic matter and other materials in soil. Gdo not have much of an appetite. Hlove to eat castings. Icannot digest organic matter in soil.

48. Standardized Test Preparation Chapter 10 3. Which of the following statements is a fact according to the passage? AEarthworms are not important for forming soil. BEarthworms only eat organic matter in the soil. CAn earthworm can eat an amount that equals half its body weight each day. DEarthworms eat little food but leave behind a lot of waste.

49. Standardized Test Preparation Chapter 10 3. Which of the following statements is a fact according to the passage? AEarthworms are not important for forming soil. BEarthworms only eat organic matter in the soil. CAn earthworm can eat an amount that equals half its body weight each day. DEarthworms eat little food but leave behind a lot of waste.

50. Standardized Test Preparation Chapter 10 Passage 2Worms are not the only living things that help create soil. Plants also play a part in the weathering process. As the roots of plants grow and seek out water and nutrients, they help break large rock fragments into smaller ones. Have you ever seen a plant growing in a crack in the sidewalk? As the plant grows, its roots spread into tiny cracks in the sidewalk. These roots apply pressure to the cracks, and over time, the cracks get bigger. As the plants make the cracks bigger, ice wedging can occur more readily. Continued on the next slide