Getting an A in Science

1. Getting an A in Science • Taking ownership or control of the information learned in class and taking responsibility for your work • This means: • Practicing (reviewing, restating, preparing) • Applying (creating, thinking, using) • Planning (studying, completing projects and homework, being prepared-pencils, books)

2. Continental Drift

3. How many continents are there? 7- North America, South America, Africa, Europe, Asia, Australia, Antarctica

4. Have the continents always looks like this?

5. Were the continents always located in the same position? http://www.youtube.com/watch?v=WaUk94AdXPA&feature=related

6. Puzzle Activity • Cut the continents apart. • Try to assemble the puzzle. • What clues did you use to help you put it back together correctly?

7. A continental puzzle

9. Discovering Earth’s Past • Using your textbook (pages 98-104) complete the worksheet on continental drift and seafloor spreading. • Worksheet is due tomorrow

10. Continental Drift • Who? • Alfred Wegener (German meteorologist) • When? • 1912 • He noticed the puzzle-like fit of the continents http://maps.google.com

11. He proposed that the continents were joined together in the past, in a large land mass called Pangaea.

14. Describe it • Over time, the continents drifted (moved) apart • Wegener named his theory “Continental Drift”.

15. He supported his theory with four pieces of evidence.

16. 1. Animal Fossil Clues • Matching fossils of animals on once connected land areas.

17. 2. Plant Fossil Clues Fossils of the plant Glossopteris are found in rocks in South Africa, India, Australia, South America, and Antarctica

18. 3. Climate Clues • Glacial evidence in Africa, South America, Australia • Fossils found in Antarctic soil indicate that the now frigid continent was once lush with trees and ferns, and home to dinosaurs, amphibians, and later, marsupials.

19. 4.Rock Clues - similarities and ages Mountains in South America and Antarctica are believed to have formed as part of the same mountain chain.

20. Wegener’s theory made sense, but no one wanted to accept it until they knew HOW the continents moved.

21. Years later someone came up with an explanation of HOW the continents moved

22. Seafloor Spreading • Who? • Harry Hess (A Princeton University scientist) • When? • 1960’s

23. Using new technology, they looked at the ocean floor • Hess and other scientists mapped the ocean floor using sonar • They detected underwater mountain ranges

24. Further examination of the ocean floor with a submarine showed underwater volcanoes. • A variety of life living near the warm vents of the volcanoes was found

25. Sampling the rocks near the volcanoes revealed that there was a pattern to their formation.

26. Describe Seafloor Spreading • Magma in the mantle rises and pushes the plates apart, forming new oceanic crust. http://www.absorblearning.com/media/item.action?quick=12n http://education.sdsc.edu/optiputer/flash/seafloorspread.htm

27. Now we could explain HOW the continents moved: Seafloor Spreading causes Continental Drift

29. He supported his theory with two pieces of evidence.

30. 1. Rock ages Youngest rocks are found at the mid-ocean ridges and they become increasingly older farther from the edges.

31. 2. Magnetic Clues • Magnetic iron particles record the time of the rock formation. • When the magnetic north pole switched places, iron in the rocks recorded this information http://www.youtube.com/watch?v=BCzCmldiaWQ http://www.absorblearning.com/media/attachment.action?quick=12w&att=2789

32. A map of the ocean floor provides even more evidence http://maps.google.com/

33. Iceland shows seafloor spreading above the water, which makes it easier to study

36. Plate Tectonic Theory • Theory of Plate Tectonics -Earth’s crust is broken into plates which float and move.

37. Earth’s crust made of many plates is similar to the shapes on a outside of a soccer ball.

38. There are about 13 plates covering Earth’s surface

39. Two Types of Plates • Continental Plates – lighter, thicker, made of granite • Oceanic Plates – heavier, thinner, made of basalt

40. Plate Boundaries (edges) When the plates move, their boundaries, or edges, can scrape each other or collide.

41. Convergent Boundary • Plates move toward each other

43. Convergent Boundary • When two continental plates move into each other, the plates combine and form mountains. (India into Asia) http://www.absorblearning.com/media/attachment.action?quick=12t&att=2783 http://www.classzone.com/books/earth_science/terc/content/visualizations/es1105/es1105page01.cfm?chapter_no=visualization

44. Convergent Boundary • When an oceanic plate runs into a continental plate, the heavier oceanic plate subducts (sinks) into the mantle and melts back into magma.

45. Volcanic mountains and deep sea trenches are created along this edge. http://www.absorblearning.com/media/attachment.action?quick=12s&att=2781

46. Oceanic plate into continental • Example: Pacific plate (oceanic) subducts (sinks) under Japan (continental).http://maps.google.com/

47. Divergent Boundary • Plates move apart

48. When both diverging plates are oceanic, it is called seafloor spreading (Mid-Atlantic Ridge)

49. When both diverging plates are continental it is called rift valley formation (Africa) http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::640::480::/sites/dl/free/0072402466/30425/19_21.swf::Fig.%2019.21%20-%20Evolution%20of%20a%20Divergent%20Plate%20Boundary

50. Transform Boundary • Plates slide past each other