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April18th, 2008

April18th, 2008. BellRinger Examples 1, 2, 3 pgs 95-97 in PSAE Coach book Objectives Describe the structure of Earth Explain how Earths dynamic processes create a changing landscape Homework What type of evidence was necessary to prove that Pangea existed?. April 21 st , 2008. BellRinger

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April18th, 2008

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  1. April18th, 2008 • BellRinger • Examples 1, 2, 3 pgs 95-97 in PSAE Coach book • Objectives • Describe the structure of Earth • Explain how Earths dynamic processes create a changing landscape • Homework • What type of evidence was necessary to prove that Pangea existed?

  2. April 21st, 2008 • BellRinger • Complete questions on pg 102, 103, & 105 • Objectives • Explain how Earths dynamic processes create a changing landscape • Homework • Complete MC questions. This will be graded!!

  3. Chapter 28 THE CHANGING EARTH

  4. The Layers of Earth

  5. The Layers of Earth • Crust- a thin surface covering the Earth. • 2 kinds: Oceanic & Continental • What is a crack in the crust called?? • Mantle- a thick molten layer between the core and the crust • Outer Core- molten iron, nickel, and oxygen • Inner Core- solid iron and nickel • The core’s temperature ranges between 2,000 oC and 5,000 oC…hot, hot, hot!

  6. Rock Cycle pg 103

  7. Igneous Rocks • Form at the surface from lava and inside the crust from magma that has cooled • Rocks that cool slowly are rougher in texture • Rocks that cool fast have smoother textures

  8. Igneous Rock

  9. Basalt

  10. Granite

  11. Sedimentary Rocks • From as a result of weathering and erosion • Formed by processes mainly at the Earth’s surface

  12. Metamorphic Rocks • Form under conditions of extreme pressure and temperature • Any type of rock can change to metamorphic under these conditions

  13. Is there a pattern??? YES!!! The Surface of Earth

  14. Continental Drift • The idea that the continents were once one landmass; a “super-continent” named Pangea • How is this possible?

  15. mantle convection Heat transferred from the core to the mantle produces a slow convection of the material in the mantle • Thermal Convection Demo

  16. Sea Floor Spreading • Mid-Ocean Ridges: mountain ranges on the ocean floor • The closer you get to a ridge, the younger the ocean floor. • Scientists concluded that the “new” land must be coming up through the ocean ridges

  17. The Theory Of Plate Tectonics • Explanation of how continents move • Earth's outer layer is made up of tectonic plates, which are moving • explains the how and why behind mountains, volcanoes, and earthquakes • What is the area called where 2 plates meet?

  18. Plate Boundaries

  19. Divergent Plate Boundaries • Plates are moving apart, allowing molten material to rise up and create new crust • Mid-ocean ridges • Sites of earthquakes and volcanoes

  20. Convergent Plate Boundaries • Occurs when two plates approach each other • Subduction: one plate slides under another • Often the site of volcanoes • Collision can also occur between approaching plates • Mountains form

  21. Convergent Plates • Subduction: • Collision:

  22. Transform Plate Boundaries • Occurs when 2 plates slide past each other • No crust is created or destroyed • Earthquakes • What “famous” transform plate boundary is located in the US?

  23. Review of Boundaries

  24. Facts & Figures: Earthquakes • Largest EQ recorded in the US: 9.2 • Largest in world: 9.5 • 500,000 detectable EQ’s each year. • More damage is caused indirectly from the EQ, not the EQ itself. • 10,000 EQ’s will develop in southern California this year. However, most will not be felt • Powerful EQ’s rocked the Midwest in the 1800’s. One recorded a magnitude of over 8 and caused church bells to ring in Boston Massachusetts • Deadliest EQ: China in 1557, killing 830,000 people

  25. Earthquakes • Defn: Vibrations of the earth’s crust from the movement of plates along faults • As plates move, they stretch/compress, and stress builds up • When the rocks break or change shape, they release stored energy in the form of movement • LIKE A RUBBER BAND! • This creates seismic waves that move through Earth

  26. Earthquakes

  27. Seismic Waves • Body Waves • originate from the center of an EQ • 2 kinds: • P waves & S Waves • Surface Waves – Move along the surface of the Earth

  28. Measuring Earthquakes • Richter scale: • Related to the amplitude of the seismic waves • More accurate for earthquakes that are near • Mercalli scale: • Uses 12 descriptive categories that describe the damage caused by earthquakes

  29. Where do Earthquakes Occur? • Along plate boundaries, faults

  30. Earthquakes in the US:SAN ANDREAS FAULT • A well known transform boundary where the Pacific plate and North American plate meet • Average rate of motion across the San Andreas Fault is 2 in./yr. (3 million years L.A. will be next to S.F.)

  31. Do EQ’s occur anywhere else in the US? YES!...it’s been a while, but there are other fault lines in the US. New Madrid fault in Midwest 250 miles long Last major EQ in 1895 Eastern US Last major EQ in 1886 Why would an EQ be so damaging in these areas today? Earthquakes in the US:OTHER FAULT LINES

  32. Where do Volcanoes Occur? Most volcanic activity is associated with plate boundaries.

  33. Where do Volcanoes Occur? Most Volcanoes occur within the Ring of Fire!

  34. Additional Sites of Volcanoes • Subducting plates beneath the ocean floor can create an island arc. • This is how the Hawaiian Islands were formed.

  35. Mount Vesuvius

  36. Mount St. Helens

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