1. © Fall 2005, Pflugerville ISD, 8th Grade 8th Grade Science

2. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Chapter 17- Plate Tectonics Section 1: Restless Continents Section 2: The Theory of Plate Tectonics Section 3: Deforming the Earth’s Crust

3. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Explain why the following statement is true or false: The state of Texas is moving to the west What Do You Think?

4. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? As the ocean floor spreads, Europe moves east and North America moves west

5. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The earth is layered like a chocolate- covered cherry

6. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The layers have different properties and different compositions

7. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The lithosphere is the cool, outermost layer of the Earth

8. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? It is divided into huge pieces called tectonic plates, which move on the asthenosphere

9. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Asthenosphere is the solid, soft layer of the mantle below the lithosphere

10. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Asthenosphere is made of mantle rock that flows slowly, allowing tectonic plates to move on it

11. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The mesosphere is the solid lower part of the mantle below the asthenosphere

12. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The outer core is the outer shell of Earth’s core. It is made of liquid iron and nickel

13. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The inner core is a sphere of solid iron and nickel

14. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The core is the solid cherry surrounded by gooey mantle covered with a thin chocolate crust

15. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Alfred Wegener 1880-1930 Alfred Wegener, a German scientist, first had the idea that continents can drift around the globe

16. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Wegener’s theory of continental drift explained why some land masses fit like puzzle pieces

17. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Continental drift also explained why similar fossils are found separated by the oceans

18. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Wegener’s theory had the continents plowing through the oceans like this ship plows through ice

19. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? As is usual with new theories, most scientists didn’t believe in continental drift

20. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Glomar Challenger In the late 1960s, this ship was designed to drill into the ocean floor for core samples

21. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The core samples revealed that rock at the center of the Atlantic (Red) was younger than rock at the edges (Blue)

22. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? The process by which new oceanic crust forms at mid-ocean ridges was called seafloor spreading

23. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Scientists later discovered that the earth’s magnetic field changes polarity every few thousand years

24. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? As the rock cools, it records these magnetic reversals in the seafloor

25. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? Alfred Wegener 1880-1930 With continental fit, seafloor spreading, and magnetic reversals as proof, Wegener’s theory was proved!

26. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Do the Continents Move? With this new theory of Plate Tectonics, Wegener’s idea of a supercontinent was accepted

27. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 The Theory of Plate Tectonics Consider the amount of energy it would take for humans to pick up a public school and move it a mile. What forces do you think cause the movement of the continents? What Do You Think?

28. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 The Theory of Plate Tectonics

29. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 The Theory of Plate Tectonics

30. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 The Theory of Plate Tectonics

31. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 The Theory of Plate Tectonics

32. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Plate Boundaries Where the plates meet, three types of plate boundaries can form…

33. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Plate Boundaries Convergent Boundary A convergent boundary is where two tectonic plates collide, or run into each other

34. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Convergent Boundaries

35. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Convergent Boundaries

36. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Convergent Boundaries

37. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Plate Boundaries Divergent Boundary A divergent boundary is where two tectonic plates separate from each other

38. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Divergent Boundary

39. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Plate Boundaries Transform Boundary A transform boundary is where two tectonic plates slide past one another horizontally

40. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Transform Boundary

41. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Settings Scientists use plate tectonics to explain how landforms like mountains and ocean basins form

42. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Settings

43. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Settings

44. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Settings

45. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Tectonic Settings

46. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust The Indian Ocean tsunami of 2004 originated at a subduction zone. How did plate tectonics cause these waves that killed over 100,000 people? What Do You Think?

47. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust

48. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust

49. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust Stress is the amount of force per unit area that is put on a rock

50. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust Strain is any change in a rock’s shape caused by stress

51. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust The deformed strata have been strained by the stress of compression

52. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust Folding is a type of strain that occurs when rocks bend

53. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Deforming the Crust Faulting is a type of strain that occurs when rock breaks

54. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains Mt. Everest, Himalayas Almost all mountains are formed at tectonic plate boundaries

55. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Divergent The mid- ocean ridge system is made of two types of mountains:

56. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Divergent Fault-block mountains form where the crust is rifting, or separating

57. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Divergent Volcanic mountains form outside of the Rift Zone, on either side

58. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Building Mountains- Convergent Convergent Boundary At convergent boundaries, either volcanic or folded mountains can form

59. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Convergent In Alaska, the subduction of the oceanic Pacific plate has created a chain of volcanoes

60. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Convergent When ocean was between India and Asia, there were volcanoes

61. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Convergent As the continents collide, they create only folded mountains

62. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Convergent The Nazca Plate is being subducted beneath the SA Plate

63. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Building Mountains- Convergent The result is a trench in the ocean and a chain of volcanoes on the continent

64. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Let’s Review! - 1 - Describe Alfred Wegener’s theory of continental drift. How is this different from the modern theory of plate tectonics?

65. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 2 Let’s Review! - 2 - What are the three possible driving forces of plate tectonics?

66. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Let’s Review! - 3 - What kind of mountains would you expect to find near an ocean trench?

67. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 3 Let’s Review! - 4 - What kinds of mountains would you expect to find at a mid-ocean ridge?

68. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 http://www.scotese.com/

69. © Fall 2005, Pflugerville ISD, 8th GradeUnit 4 : Chapter 17 : Section 1 Pre-AP Extensions