Bell Ringer Take out a sheet of paper, put your name on it. Write your answer to the questions.

1. Bell RingerTake out a sheet of paper, put your name on it. Write your answer to the questions. • What type of tectonic activity made Hawaii? • What activity within the mantle causes plate movement? • What type of erosion created the Great Lakes? • What type of plate boundary is the San Andreas fault in California. • What type of external force of change carries away pieces of rock and creates sediment?

2. Forces of Change

3. I. Earth's Structure

4. Earth is composed of 3 layers: • Core • Mantle • Crust

5. Core (inner & outer) – made of iron & nickel a. inner – super hot solid -about 4,000 mi. below surface of earth b. outer – super hot liquid -about 1,800 mi. below the surface of earth -temperatures can reach 8,000*F

6. Mantle -hot, dense mostly liquid rock -pockets of magma (rise & fall) -made of silicon, aluminum, iron, magnesium, and oxygen

7. Crust -rocky shell which forms earth’s surface -broken into more than a dozen slabs of rock called plates that rest on layer of the upper mantle -these plates carry earth’s oceans & continents

8. II. Plate Movement

9. -Continental Drift : theory that continents were once joined and then slowly drifted apart *super-continent was called Pangaea

10. PANGEA

12. -Plate Tectonics – term scientists use to describe the activities of continental drift and magma flow which create many of Earth’s physical features *plates crash into each other, pull apart, or grind and slide past each other (about 4 inches or less per year)

13. -Why do plates move? -convection currents *hotter material is less dense & rises (toward crust of Earth) *cooler material is more dense & sinks (toward core of Earth) *creates continuous circular motion/movement

14. Why might a scientist want to study plate tectonics?

15. III. Internal Forces of Change

16. -Plates move apart (rift) from each other (tension) 1. Continental-Continental = creates gap (rift valley) in which water can flow in *ex: Red Sea; Great Rift Valley Divergent Boundary

18. Oceanic-Oceanic = magma rises up & creates new crust on edges of the 2 plates -enlarges the ocean floor & forms underwater mountain ranges called ocean ridges *example: Mid-Atlantic Ridge – North American plate & Eurasian & African plates pulling apart

21. In general: Plates move toward each other & collide (compression) One plate is forced below the other (subduction) Convergent Boundary

22. Oceanic-Continental -subduction occurs = heavier sea plate dives beneath lighter continental plate *sea plate begins to melt into magma  pressure builds  magma bursts thru crust to form volcanic mtns *ex: Andes Mountains in S. America – collision of Nazca and SA plates

24. Oceanic- Oceanic -subduction occurs *sea plate begins to melt & magma rises to ocean surface in form of volcanic islands *example: Philippine islands- collision of Philippine & Pacific plates

26. Continental- Continental -pressure builds until one plate is subducted *sometimes sinking plate melts & rises as volcanic mountains are formed *example: Himalaya mountains (South Asia) – collision of Indian & Eurasian plate

28. -Plates slide past each other along faults (cracks in the earth’s crust) - Crust is pulled and stretched (tension) until tension is released (Earthquake) Transform Boundary

29. -example: San Andreas Fault in California

31. HOT SPOTS -Magma rises thru the tectonic plate -The magma erupts on the surface as lava & hardens to form volcanic islands -Magma continues to rise from the hot spot, building up an undersea volcano that will one day become an island -a chain is formed

32. Animations Hot Spot Animation

33. Guess the Tectonic Activity!

34. Oceanic-Oceanic Convergent

35. Oceanic-Oceanic Divergent

36. Transform

37. Continental-Continental Convergent

38. Continental-Continental Divergent

39. Oceanic-Continental Convergent