1. Earth Science Chapter 5
Plate Tectonics

2. Convection and the Mantle Drifting continents Sea-floor Spreading
Big Ideas
Earth’s Interior
Convection and the Mantle
Drifting continents
Sea-floor Spreading
Plate Tectonics

3. How far do you think it is to the center of the Earth?
Earth’s Interior
How far do you think it is to the center of the Earth?

4. Almost 4,000 miles!
The deepest mine in the world is only 2 miles

5. How do you think scientists know about the center of the Earth?

6. Geologists use 2 main types of evidence to learn about Earth’s interior:
Direct Evidence from rock samples
Indirect evidence from seismic waves

7. Humans have drilled holes and extracted rock from depths of 12 miles
Evidence from Rocks
Humans have drilled holes and extracted rock from depths of 12 miles
Blasts from the Earth have brought rocks from 100 ft to the surface

8. Evidence from Seismic Waves
Earthquakes produce seismic waves
The speed of seismic waves and the path they take show the structure of the planet

10. The three main layers of Earth are the crust, mantle, and the core
These layers differ in size, composition, temperature, and pressure

12. Temperature
The first 20 meters beneath Earth’s crust is cool
After this depth, temperature rises 1 degree Celsius per 40 meters
Heat comes from the molten layer and radioactive substances

13. The deeper you go, the higher the pressure
This pressure is equal to that of a swimming pool

14. Pressure

15. Lab Skills Activity Work with a partner,
Read the directions to the Lab Zone Skills Activity
Create the Data Table on page 129

16. Crust is a layer of rock that forms Earth’s outer skin
Crust includes both dry land and ocean floor
Crust is very thin compared to the other layers of Earth, only 5-70 km thick

17. Crust

18. Crust
The crust beneath the ocean is oceanic crust and usually made of basalt
Continental crust consists of rocks such as granite

19. Mantle
The mantle is about 40 km below the surface
It consists of a hot, solid rock
It can be divided into layers
The mantle is about 3000 km thick

20. Mantle

21. Lithosphere
The crust and the uppermost part of the mantle form the lithosphere
It is about 100 km thick
Lithos means “stone” in Greek

22. Lithosphere

23. Asthenosphere
Under increase heat and pressure
Less rigid-soft like tar, but still solid
Asthenes means “weak” in Greek

25. Beneath the asthenosphere the mantle is solid
The Lower Mantle
Beneath the asthenosphere the mantle is solid
This material extends to the Earth’s core

26. Lower Mantle

27. The Core
Consists of mostly nickel and iron
Made of two parts, a liquid outer core and solid inner core
Together it is about 3486 km thick

28. Despite extreme pressure, the outer core is molten surrounding a dense, solid inner core
Evidence suggests that the extreme pressure in the inner core will not allow the solid metal to spread and become liquid

29. Core

30. Core and Magnetic field
Scientists think that movements in Earth’s liquid outer core create Earth’s magnetic field.
This magnetism is what attracts a compass’ needle towards north (it aligns with Earth’s magnetic field)

32. Individually
Complete the section 1 assessment on page 131, including the “writing in science” assignment. If you do not complete these in class, they will become your homework and will be due tomorrow.

33. OPEN NOTE POP QUIZ
QUIETLY TAKE OUT A PIECE OF PAPER AND ANSWER THE GFOLLOWING QUESTIONS:
1. WHAT TYPE OF EVIDENCE DO SCIENTISTS USE TO LEARN ABOUT EARTH’S INTERIOR?
2. WHAT HAPPENS TO TEMPERATURE AS YOU TRAVEL INTO EARTH’S INTERIOR?
3. GIVE A BRIEF DESCRIPTION OF THE THREE MAIN LAYERS OF EARTH’S INTERIOR.

34. Make a Chart Types of Heat Transfer Radiation Explanation/definition
Conduction
Explanation/Definition
Convection

35. When you complete the chart
Read the sections “Convection Currents”, and “Convection Currents in Earth.”
1. Define Convection Currents
2. Explain how convection currents work, using a real example
3. Create an illustration of a convection current

36. Bellwork
What are the three types of heat transfer and give an example of one that is not in your book!

37. What are some of your theories as to what made scientists wonder about drifting continents in the first place?

38. Drifting Continents

39. Prior to Columbus, mapmakers did not know about the new worlds
Continental Drift
Prior to Columbus, mapmakers did not know about the new worlds
Shortly after they began to notice how the coastlines of several countries seemed to fit together like a puzzle

41. Early 1900s German Scientist Alfred Wegener made a hypothesis:
Continental drift
Early 1900s German Scientist Alfred Wegener made a hypothesis:
All of the continents were once joined together in a single land mass and have since drifted apart.

42. The Origin of Continents and Oceans
Wegener gathered evidence from different scientific fields to support his ideas about continental drift.
He studied land features, fossils, and evidence of climate change

43. Write a Book! Make your own version of Wegner’s book
Use the same title as he did
Read pages about the evidence he found
Create a page for each type of evidence
Explain how the evidence supports his hypothesis and include illustrations if appropriate.

44. The Origin of Continents and Oceans
Page 1: Title
Page 2: Evidence from land features
Page 3: Evidence from fossils
Page 4: Evidence from climate
Page 5: Conclusion

45. WHAT DID YOU FIND?
In your notebook, write what you found from Wegner’s evidence.

46. Review Game
Each group take out a piece of paper
With your desk partner, you will quietly discuss and write your answer to the following questions
The group with the most points at the end of the game will get to choose a homemade treat from me;-)

47. How far is it to the center of the Earth?
2 pts
How far is it to the center of the Earth?
4000 miles

48. 2 pts
Geologists use 2 main types of evidence to learn about Earth’s interior, what are they?
Seismic waves and rock samples

49. 2 pts
What are the three main layers of the Earth?
Core, Mantle, Crust

50. 2 pts Describe Earth’s outer most layer
Made of Rocks, includes Earth’s Land, Mountains, and water, only 5-70 km thick, thinnest layer

51. 2 pts Describe Earth’s middle layer
Mantle, several different layers, made of different materials and containing different textures.

52. 2 pts Describe Earth’s inner most layer (include both sub layers)
Inner and outer core, both are made of nickle and iron, outer is liquid, inner is solid, outer core determines Earth’s magnetic poles

53. 2 pts
What happens to the temperature are you travel into Earth’s interior?
Cooler for the first 20 meters, then it begins to become hotter at a constant rate of increase

54. 3 pts What are the three types of heat transfer?
Radiation, conduction, convection

55. 2 pts Explain radiation and give an example
Transfer of heat energy through space, sun’s radiating heat

56. 2 pts Explain conduction and give an example
Transfer of heat energy directly from the heat source…by touch, touching something hot

57. 2 pts Explain conduction and give an example
Movement of heated material from heat source to cooler space, creates a cycle the circulates heated and cooled material. Mocement of hotter and cooler water in a heated pot

58. 3 pts What was Alfred Wegner’s hypothesis?
The continents were once joined together in one super continent

59. 3 pts
What were the three main sources of evidence Alfred used to support his thesis?
Fossils, land features, climate change evidence

60. 2 pts
Explain and give an example of Wegner’s evidence from land features.

61. 2 pts
Explain and give an example of Wegner’s evidence from fossils

62. 2 pts
Explain and give an example of Wegner’s evidence from climate.

63. Why was Wegner’s hypothesis not accepted by the scientific community?

64. Who was Harry Hess and how was he connected to Alfred Wegner?

65. Explain the theory of sea-floor spreading

66. What were all of the pieces of evidence Hess used to support his thesis?

67. How does the existence of lava pillows at deep ocean trenches help support Hess’ theory?

68. How does magnetic stripes help support Hess’ theory?

69. How do core samples from the ocean floor help support Hess’ theory?

70. What tends to occur at deep ocean trenches and why?

71. Explain how the atlantic ocean is getting bigger and the Pacific is getting smaller.

72. Sea-Floor Spreading

73. Mid Ocean Ridges

74. Mid Ocean Ridge
Curve like seams through Earth’s oceans
Most mountains are under water, except Iceland!

75. Iceland

76. Hess and Sea-floor spreading
Harry Hess in 1960 realized that Wegener was right and the continents were being moved by sea-floor spreading:
The sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added
The ocean floors act like conveyor belts carrying the continents along with them

78. Read pages

79. Editorial You are Harry Hess! (or Harriet Hess)
You have just concluded your research about sea-floor spreading
Prepare a speech for your science conference in which you will share your findings
Include your theory, the evidence that supports if from molten material, magnetic stripes, and drilling samples, and end with a conclusive argument!

80. For Pace http://www.youtube.com/watch?v=hSdlQ8x7cuk
Future of continental drift

81. Sea floor spreading

82. Sea floor spreading
Magnetic Stripes

83. http://earthguide. ucsd

84. Bellwork
What were the hypotheses of both Alfred Wegner and Harry Hess and how were they connected?

85. http://www.youtube.com/watch?v=q_IYQdKkWsU Ice Age
Bill Nye

86. http://maccallum. wikispaces

87. Subduction at Trenches
Deep-ocean trenches: deep underwater canyons.
At deep-ocean trenches the oceanic crust bends down and sinks beneath the continental crust.

91. Subduction
Subduction: the process by which ocean floor sinks beneath the deep ocean trench and back into the mantle

92. Short Subduction Video

93. Process of Subduction
As the older rock is subducted, younger rock moves away from the mid-ocean ridge
New rock is hot, but it cools and becomes more dense as it ages

94. Old rock, Green Rock, New Rock, Red Rock

95. Bellwork
Describe the difference between what occurs at the mid ocean ridge and deep ocean trenches.

96. Subduction

97. Eventually gravity pulls the older, denser rock down at the trenches
Process Continued
Eventually gravity pulls the older, denser rock down at the trenches

98. Subduction and Earth’s Oceans
Subduction and seafloor spreading can change the size and shape of the oceans
Ocean floor is renewed about every 200 million years
The Pacific’s trenches are eating more crust than the ridges can make
In the Atlantic the opposite is the case

99. Future Pangea

100. http://www.youtube.com/watch?v=xsJn8izcKtg Lava Pillows
Ridge Volcano

101. Review
Continental Drift Review

102. Bellwork
Briefly discuss the progression of ideas and discoveries beginning with Alfred Wegener and ending with Plate Tectonics.
Don’t ask questions, just write….remember you cannot get bellwork wrong!

103. Flip Book Title The Theory of Plate Tectonics
Make a flip book describing the 3 types of plate boundaries
Your book will need a
Title
The Theory of Plate Tectonics
Page on each:divergent, convergent, and transform boundaries
Each page should define the type of boundary, explain what types of landforms that occur at these boundaries, and have an illustration

104. BELLWORK
What are the three types of boundaries and which one is most likely to produce earthquakes?

106. The Theory of Plate Tectonics

107. Boundaires
Divergent
Convergent
Transform

108. Divergent
are where plates are moving away from each other. This movement is found along the mid-ocean ridges where new crust material is being created.

109. Mid-Ocean Ridge, Rift Valleys
African Rift Valley

111. Continent-Continent

113. Ocean-Ocean

114. Continent-Continent

115. Transform

116. Complete your book for homework
Quiz tomorrow
Complete your book for homework
Bring it with you tomorrow and you may use it for our quiz over boundaries