2. Chapter Menu Chapter Introduction Lesson 1Lesson 1Plate Tectonics Lesson 2Lesson 2Earthquakes and Volcanoes Lesson 3Lesson 3Weathering, Erosion, and Deposition Chapter Wrap-Up

3. Chapter Introduction How do natural processes change Earth’s surface over time?

4. 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.

5. Chapter Introduction 1.Continents do not move. 2.Earth’s mantle is liquid. 3.Earthquakes occur and volcanoes erupt only near plate boundaries. 4.Volcanoes erupt melted rock. Do you agree or disagree?

6. Chapter Introduction 5.Rocks cannot change. 6.Sediment can be transported by water, wind, and ice. Do you agree or disagree?

7. Lesson 1 Reading Guide - KC What is the theory of plate tectonics? What evidence do scientists use to support the theory of plate tectonics? How do the forces created by plate motion change Earth’s surface? Plate Tectonics

8. Lesson 1 Reading Guide - Vocab plate tectonics continental drift convergent boundaryconvergent boundary divergent boundarydivergent boundary Plate Tectonics transform boundarytransform boundary subduction zonesubduction zone compression tension shear

9. Lesson 1-1 The theory of plate tectonics states that Earth’s crust is broken into rigid plates that move slowly over Earth’s surface.plate tectonics The rigid plates are called tectonic plates. North America is part of the North American Plate. Plate Motion

10. Lesson 1-1 The movement of one plate is described as either moving away from or toward another plate, or sliding past another plate. Plates move at speeds of only a few centimeters per year. At this rate, it takes moving plates millions of years to make new continents, new mountain ranges, or other landforms. Plate Motion (cont.)

11. Lesson 1-1 Plate Motion (cont.) What is the theory of plate tectonics?

12. Lesson 1-1 Long before geologists proposed the theory of plate tectonics, they discovered evidence of continental movement. Plate Motion (cont.) Photo by G.K. Gilbert, U.S. Geological Survey

13. Lesson 1-1 In 1912, Alfred Wegener developed the hypothesis that continents move, called continental drift.continental drift One piece of evidence is the shape of Earth’s continents. Plate Motion (cont.)

14. Lesson 1-1 Fossil and rock evidence from the Gondwana continents also supports the hypothesis of continental drift. Plate Motion (cont.)

15. Lesson 1-1 Geologists have discovered the same types of fossils on continents that are now separated by vast oceans.

16. Lesson 1-1 Plate Motion (cont.) What evidence do scientists use to support the theory of plate tectonics?

17. Lesson 1-1 Plate Motion (cont.) Convection affects the mantle underneath tectonic plates. Hotter mantle rises toward Earth’s surface and cooler mantle sinks deeper into the mantle.

18. Lesson 1-1 Plate Motion (cont.) As the Earth’s mantle moves, it pushes and pulls tectonic plates over Earth’s surface.

19. Lesson 1-2 The edges of tectonic plates are called plate boundaries. A convergent boundary is where two plates move toward each other.convergent boundary A divergent boundary is where two plates move apart from each other.divergent boundary A transform boundary is where plates slide horizontally past each other.transform boundary Tectonic Plate Boundaries

20. Lesson 1-2 When two plates come together, the denser oceanic plate usually is forced down into the mantle and the less dense continental plate remains on Earth’s surface. The area where one plate slides under another is called a subduction zone. subduction zone

21. Lesson 1-2 When two continents collide at a plate boundary, both continents remain on the surface. As two continents push together, the crust rises up and large mountains form. Tectonic Plate Boundaries (cont.)

22. Lesson 1-2 When plates move apart at divergent boundaries, a rift forms between the two plates. A rift can form within continents when continental crust moves in opposite directions. Tectonic Plate Boundaries (cont.)

23. Lesson 1-2 A rift also can form at divergent boundaries on the ocean floor. As plates separate, molten rock can erupt from the rift. As the molten rock cools, it forms new crust. Tectonic Plate Boundaries (cont.)

24. Lesson 1-2 Tectonic plates slide past each other at transform boundaries. The two sides of the boundary move in opposite directions. This can deform or break features such as fences, railways, or roads that cross the boundary. Tectonic Plate Boundaries (cont.)

25. Lesson 1-2 Tectonic Plate Boundaries (cont.) transform Science Use horizontal relative motion Common Use to change

26. Lesson 1-3 Forces within Earth cause plates to move. The three types of plate boundaries experience different types of forces. Forces Changing Earth’s Surface

27. Lesson 1-3 The squeezing force at a convergent boundary is called compression. compression The pulling force at a divergent boundary is called tension.tension The side-by-side dragging force at transform boundaries is called shear. shear

28. Lesson 1-3 Even though plates move slowly, the forces at plate boundaries are strong enough to form huge mountains and powerful earthquakes. Tensional forces pull the land apart and form rift valleys and mid-ocean ridges. Compressional forces form mountains. Forces Changing Earth’s Surface (cont.)

29. Lesson 1-4 Forces Changing Earth’s Surface (cont.) How do the forces created by plate motion change Earth’s surface?

30. Lesson 1 - VS Evidence of continental drift includes fossils, mountain ranges, rock types, and the shapes of continents. Earth’s crust is broken into pieces called tectonic plates. Convection currents in the mantle cause the plates to move.

31. Lesson 1 - VS There are three types of tectonic plate boundaries. Movement occurs at all three boundaries.

32. Lesson 1 – LR1 Which boundary is between two plates moving toward each other? A.convergent B.divergent C.subduction D.transform

33. Lesson 1 – LR2 A.convergent B.divergent C.subduction D.transform Which zone describes the boundary where one plate slides under another plate?

34. Lesson 1 – LR3 A.shear B.tension C.compression D.continental drift Which is the side-by-side dragging force at transform boundaries?

35. Lesson 1 - Now 1.Continents do not move. 2.Earth’s mantle is liquid. Do you agree or disagree?

36. Lesson 2 Reading Guide - KC What causes earthquakes? What causes volcanoes to form? How do earthquakes and volcanoes change Earth’s surface? Earthquakes and Volcanoes

37. Lesson 2 Reading Guide - Vocab earthquake fault mid-ocean ridge hot spot Earthquakes and Volcanoes lava flow volcanic ash caldera

38. Lesson 2-1 Because tectonic plates move very slowly, most changes to Earth’s surface take a long time. But some changes occur very quickly and violently. Earthquakes

39. Lesson 2-1 An earthquake is the rupture and sudden movement of rocks along a break or a crack in Earth’s crust.earthquake Dr. Roger Hutchinson/NOAA

40. Lesson 2-1 The surface along which the crust moves is called a fault. fault When pieces of crust slide past each other, energy is released, causing the ground to shake. Earthquakes (cont.) Photograph by N.J. Silberling, USGS Photo Library, Denver, CO

41. Lesson 2-1 Earthquakes (cont.) What causes earthquakes?

42. Lesson 2-1 Most earthquakes occur near plate boundaries, though some occur very far from plate boundaries.

43. Lesson 2-1 Compression and tension forces produce ridges and mountains as Earth’s crust moves vertically. Liquefaction refers to when extreme shaking causes ground that is made up of loose sediment to behave more like a liquid than a solid. Earthquakes can trigger landslides, which bring rocks and soil from the tops of mountains into valleys. Earthquakes (cont.)

44. Lesson 2-1 Earthquakes that happen underwater can cause tsunamis—huge ocean waves created by movement at a fault. Earthquakes (cont.)

45. Lesson 2-1 Earthquakes (cont.) How do earthquakes change Earth’s surface?

46. Lesson 2-2 Volcanoes are landforms that form when magma erupts onto Earth’s surface as lava. Volcanoes can occur at divergent and convergent plate boundaries and at hot spots. Volcanoes

47. Lesson 2-2 The mountains that form as lava from a volcano at a divergent boundary builds up and cools are called mid-ocean ridges.mid-ocean ridges

48. Lesson 2-2 At some convergent boundaries, one tectonic plate sinks, melts the mantle, and forms magma that erupts onto the plate that does not sink.

49. Lesson 2-2 Hot spots are locations where volcanoes form far from plate boundaries.Hot spots The Hawaiian Islands in the middle of the Pacific Ocean and Yellowstone National Park in Wyoming are hot spots. Volcanoes (cont.)

50. Lesson 2-3 Because magma is hot, it is also less dense than the rock material around it. Rising magma and great pressure caused by dissolved gases eventually erupt through cracks in Earth’s surface, creating a volcano. Volcanoes (cont.)

51. Lesson 2-3 Most of Earth’s largest volcanoes are located at convergent plate boundaries.

52. Lesson 2-3 What causes volcanoes to form? Volcanoes (cont.)

53. Lesson 2-4 When melted mantle material erupts, it flows over Earth’s surface, creating long streams of molten rock called lava flows.lava flows The lava eventually cools and solidifies, forming solid rock. Volcanoes (cont.) Royalty-Free/CORBIS

54. Lesson 2-4 At convergent plate boundaries, part of the continental crust can become mixed with magma from the mantle. When this mixture of molten materials erupts, it does not flow as easily as lava made only of melted mantle. Instead of forming lava flows, it often solidifies in the atmosphere, where it breaks into small pieces of lava called volcanic ash. volcanic ash Volcanoes (cont.)

55. Lesson 2-4 Eruptions that eject ash high into the atmosphere are called explosive eruptions. Lava also can be produced during these eruptions. Volcanoes (cont.)

56. Lesson 2-5 Shield volcanoes form after basaltic lava flows have occurred over time. Shield volcanoes tend to be large with gentle slopes. J.S. Griggs/U.S. Geological Survey

57. Lesson 2-5 Composite volcanoes form as lava flows and ash layers deposited by explosive eruptions build up. Composite volcanoes often have steep sides and a cone shape. PhotoLink/Getty Images

58. Lesson 2-5 Before a volcano erupts, magma builds up in the crust in a reservoir called a magma chamber.

59. Lesson 2-5 Sometimes the surface above the chamber collapses, creating a large depression in the center of the volcano called a caldera.caldera P.W. Lipman, U.S. Geological Survey

60. Lesson 2-5 Volcanoes (cont.) caldera from Latin caldārium, means “warming”

61. Lesson 2-6 Volcanic ash and gases from explosive eruptions can blow high into the atmosphere, blocking sunlight. This can cause the temperature of the atmosphere near Earth’s surface to decrease. P.W. Lipman, U.S. Geological Survey

62. Lesson 2-6 Volcanoes (cont.) How do volcanoes change Earth’s surface?

63. Lesson 2 - VS Earthquakes occur when movement along a fault occurs. Earthquakes occur mostly along plate boundaries. They can cause great damage. Volcanoes form at two types of plate boundaries. Lava cools and builds up, forming volcanoes and other landforms.

64. Lesson 2 - VS Earthquakes and volcanoes change the surface by building mountains, covering land with lava, and shifting the surface along faults.

65. Lesson 2 – LR1 Which happens when extreme shaking causes sediment to behave more like a liquid than a solid? A.compression B.eruption C.liquefaction D.tsunami

66. Lesson 2 – LR2 A.mid-ocean ridge B.lava flow C.fault D.caldera Which is a long stream of molten rock which eventually cools, solidifies, and builds up over time as flat layers?

67. Lesson 2 – LR3 A.caldera B.composite C.mid-ocean D.shield Which type of volcano often has steep sides and is cone shaped?

68. Lesson 2 - Now 3.Earthquakes occur and volcanoes erupt only near plate boundaries. 4.Volcanoes erupt melted rock. Do you agree or disagree?

69. Lesson 3 Reading Guide - KC How are weathering and soil formation related? How do weathering, erosion, and deposition change Earth’s surface? How are erosion and deposition related? Weathering, Erosion, and Deposition

70. Lesson 3 Reading Guide - Vocab weathering erosion physical weathering chemical weathering Weathering, Erosion, and Deposition soil sediment deposition

71. Lesson 3-1 Weathering refers to the processes that break down rocks, changing Earth’s surface over time.Weathering Erosion is the moving of weathered material, or sediment, from one location to another.Erosion Weathering

72. Lesson 3-1 Slowly but surely, weathering and erosion wear down mountains. Weathering (cont.) Photo by Tim McCabe, USDA Natural Resources Conservation ServiceDr. Parvinder Sethi

73. Lesson 3-1 The process of breaking rock into small pieces without changing the composition of the rock is physical weathering.physical weathering Frost wedging is what occurs when water in rocks freezes and melts repeatedly, breaking the rocks apart. Weathering (cont.)

74. Lesson 3-1 The roots of plants can grow into cracks in rock and eventually break the rock. Weathering (cont.)

75. Lesson 3-1 The process of changing the composition of rock and minerals by exposure to water and the atmosphere is called chemical weathering. chemical weathering Gases in the atmosphere can cause chemical weathering. Weathering (cont.)

76. Lesson 3-1 Weathering (cont.) How does weathering change Earth’s surface?

77. Lesson 3-1 Physical weathering exposes more surface area of rocks, allowing more water and atmospheric gases to enter rocks. Chemical weathering weakens rocks by changing the composition of some minerals and dissolving others. Weathering (cont.)

78. Lesson 3-1 Soil consists of weathered rock, mineral material, water, air, and organic matter from the remains of organisms.Soil Soil forms directly on top of the rock layers from which it is made and is the result of hundreds to thousands of years of weathering. Weathering (cont.)

79. Lesson 3-1 Soil formation begins when physical and chemical weathering break down rocks.

80. Lesson 3-1 Soil formation begins when physical and chemical weathering break down rocks.

81. Lesson 3-1 Warm, wet climates produce soil fastest. Large amounts of rain can speed weathering of rocks, and chemical reactions are faster in warmer temperatures. Weathering (cont.)

82. Lesson 3-1 Weathering (cont.) How are weathering and soil formation related?

83. Lesson 3-2 The minerals and small pieces of rock produced by weathering are called sediment. sediment Moving water causes erosion by picking up rock pieces and sediment, which scrape along the ground picking up more material. Erosion

84. Lesson 3-2 Large masses of ice, called glaciers, cause erosion by flowing down a mountain and removing rock and sediment. Erosion by glaciers makes deep valleys and steep peaks.

85. Lesson 3-2 Strong winds also can erode and move sediment. Soil and rock that are not protected by plants can be eroded by wind. U.S. Department of Agriculture

86. Lesson 3-2 How does erosion change Earth’s surface? Erosion (cont.)

87. Lesson 3-3 Deposition is the process of laying down eroded material in a new location.Deposition If the speed of flowing water decreases, the water can no longer carry sediment and the sediment settles at the bottom of the water. Floodplains form when sediment settles out of rivers that flood the areas next to them. Deposition

88. Lesson 3-3 When glaciers melt, the water produced by the melting ice does not flow fast enough to carry sediment. Glacial deposits of sediment are called moraines.

89. Lesson 3-3 Wind also can deposit sediment. Sand dunes are landforms made as wind continually moves and deposits sand grains. Tim McCabe/NRCS

90. Lesson 3-4 How does deposition change Earth’s surface? Deposition (cont.)

91. Lesson 3-4 The locations where sediment accumulates are called sedimentary basins. Sediment continues to be deposited in low areas and then forced upward as tectonic activity forms mountains. Deposition (cont.)

92. Lesson 3-4 How are erosion and deposition related? Deposition (cont.)

93. Lesson 3 - VS Physical and chemical weathering work together and change Earth’s surface. They break down rock and form sediment. Erosion occurs when sediment is removed and transported from where it formed. Deposition occurs when sediment is laid down in new locations.

94. Lesson 3 – LR1 Which process breaks rock into small pieces without changing the composition of the rock? A.deposition B.erosion C.chemical weathering D.physical weathering

95. Lesson 3 – LR2 A.glaciers B.sand dunes C.sediment D.soil Which are the minerals and small pieces of rock produced by weathering?

96. Lesson 3 – LR3 A.soil B.glacier C.sand dune D.sedimentary basin Which location accumulates sediment?

97. Lesson 3 - Now 5.Rocks cannot change. 6.Sediment can be transported by water, wind, and ice. Do you agree or disagree?

98. Chapter Review Menu Key Concept Summary Interactive Concept Map Chapter Review Standardized Test Practice

99. The BIG Idea Mountains and valleys form where tectonic plates interact, new crust forms where lava flows from volcanoes, and the land shifts when earthquakes occur.

100. Key Concepts 1 The theory of plate tectonics states that Earth’s surface is broken into rigid pieces, or plates, that move with respect to each other. Evidence that continents have moved throughout Earth’s history includes the shape of the continents and the presence of similar fossils and geological features on widely separated continents. The forces produced by plate motion change Earth’s surface by forming mountains and rifts and by causing earthquakes and volcanic eruptions. Lesson 1: Plate Tectonics

101. Key Concepts 2 Lesson 2: Earthquakes and Volcanoes Earthquakes are caused when forces on rocks in the crust become large enough for the rock to move along faults. Volcanoes form when rocks in the mantle become hot enough to melt and the molten rock erupts onto Earth’s surface. Earthquakes and volcanoes change Earth’s surface in several ways. They form mountains and new landmasses from lava flows and explosive eruptions.

102. Key Concepts 3 Physical weathering and chemical weathering break down material on Earth’s surface. Soil can form as a result. Weathering changes Earth’s surface by breaking down material and forming soil. Erosion and deposition by water, wind, and ice create and change landforms. Sediment is removed by erosion, and deposition lays down sediment in a new location. Lesson 3: Weathering, Erosion, and Deposition

103. Chapter Review – MC1 A.compression B.continental drift C.plate tectonics D.transform boundaries Alfred Wegener proposed which hypothesis in 1912?

104. Chapter Review – MC2 A.compression B.continental drift C.shear D.tension Which describes the pulling force at a divergent boundary?

105. Chapter Review – MC3 A.faults B.hot spots C.mid-ocean ridges D.tsunami Which form as lava at a divergent boundary that builds up and cools?

106. Chapter Review – MC4 A.above earthquakes B.between mid-ocean ridges C.over hot spots D.under faults Where do volcanoes form far from plate boundaries?

107. Chapter Review – MC5 A.deposition B.erosion C.chemical weathering D.physical weathering Which is the movement of sediment from one location to another?

108. Chapter Review – STP1 A.convection B.continental drift C.divergent boundaries D.plate tectonics Which theory states that Earth’s crust is broken into rigid plates that move slowly over Earth’s surface?

109. Chapter Review – STP2 A.tension B.shear C.convection D.compression Which force forms rift valleys and mid-ocean ridges?

110. Chapter Review – STP3 A.earthquake B.fault C.lava flow D.volcano Which is the rupture and sudden movement of rocks along a break or a crack in Earth’s crust?

111. Chapter Review – STP4 A.volcanic ash B.mid-ocean ridge C.lava flow D.hot spot Which is molten material that solidifies in the atmosphere and breaks into small pieces of lava?

112. Chapter Review – STP5 A.deposition B.erosion C.chemical weathering D.physical weathering Which process changes the composition of rock and minerals by exposure to water and the atmosphere?