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Chapter Introduction Lesson 1 Weathering Lesson 2 Soil Chapter Wrap-Up. Chapter Menu. What natural processes break down rocks and begin soil formation?. Chapter Introduction. What do you think?.

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

  2. What natural processes break down rocks and begin soil formation? Chapter Introduction

  3. 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. Chapter Introduction

  4. 1. Weathering is the same as erosion. 2. Humans are the main cause of weathering. 3. Plants can break rocks into smaller pieces. Do you agree or disagree? Chapter Introduction

  5. 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. Do you agree or disagree? Chapter Introduction

  6. 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? Lesson 1 Reading Guide - KC

  7. Weathering • weathering • mechanical weathering • chemical weathering • oxidation Lesson 1 Reading Guide - Vocab

  8. Weathering and Its Effects • The mechanical and chemical processes that change objects on Earth’s 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. Lesson 1-1

  9. Weathering and Its Effects(cont.) weather Science Use to change from the action of the environment Common Use the state of the atmosphere Lesson 1-1

  10. Weathering and Its Effects(cont.) How does weathering break down or change rock? Lesson 1-1

  11. Mechanical Weathering • When physical processes naturally break rocks into smaller pieces,mechanical weatheringoccurs. • The chemical makeup of a rock stays the same during mechanical weathering. • Mechanical weathering can be caused by ice wedging, abrasion, plants, and animals. Lesson 1-2

  12. Lesson 1-2

  13. 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. Lesson 1-2

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

  15. Chemical Weathering • Chemical weatheringchanges 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 Lesson 1-3

  16. 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. Lesson 1-3

  17. Chemical Weathering(cont.) • Oxidationcombines 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. Lesson 1-3

  18. Chemical Weathering(cont.) How does chemical weathering change rock? Lesson 1-3

  19. 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. Lesson 1-4

  20. 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. Lesson 1 - VS

  21. 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 Lesson 1 - VS

  22. The minerals that make up rock change during which of these? A. mechanical weathering B. chemical weathering C. ice wedging D. abrasion Lesson 1 – LR1

  23. Which of these are agents of chemical weathering? A. water B. acids C. animals D. A and B Lesson 1 – LR2

  24. 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 Lesson 1 – LR3

  25. 1. Weathering is the same as erosion. 2. Humans are the main cause of weathering. 3. Plants can break rocks into smaller pieces. Do you agree or disagree? Lesson 1 - Now

  26. 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? Lesson 2 Reading Guide - KC

  27. Soil • soil • organic matter • pore • decomposition • parent material • climate • topography • biota • horizon Lesson 2 Reading Guide - Vocab

  28. What is soil? • Soilis a mixture of weathered rock, decayed organic matter, mineral fragments, water, and air. • Organic matteris the remains of something that was once alive. • Decompositionis the process of changing once-living material into dark-colored organic matter. Lesson 2-1

  29. What is soil?(cont.) Soil contains gases that fill the soil pores–the small holes and spaces in soil. pore from Greek poros, means “passage, way” Lesson 2-1

  30. What is soil?(cont.) The sizes of pores change with differences in particle size. Lesson 2-1

  31. 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. Lesson 2-1

  32. Formation of Soil(cont.) • Parent materialis the starting material of soil. • Parent material is made of the rock or sediment that weathers to form the soil. Lesson 2-2

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

  34. 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. • Topographyis the shape and steepness of the landscape. Lesson 2-2

  35. 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. Lesson 2-2

  36. 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. Lesson 2-2

  37. Rock and soil are affected by organism activity. Lesson 2-2

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

  39. Mature soils develop layers as new soil forms on top of older soil. Lesson 2-2

  40. Horizons • As time passes, weathering is constantly acting on rock and sediment, making soil formation a constant, but slow, process. • Horizonsare layers of soil formed from the movement of the products of weathering. Lesson 2-2

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

  42. 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. Lesson 2-3

  43. Horizons(cont.) What are soil horizons? Lesson 2-3

  44. Soil Properties and Uses Lesson 2-4

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

  46. 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. Lesson 2-4

  47. 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. Lesson 2-4

  48. 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? Lesson 2-4

  49. The type of soil formed depends partly on climate. Lesson 2-4

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

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