1. April18th, 2008 BellRinger Objectives Homework
Examples 1, 2, 3 pgs 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 Objectives Homework
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. The Surface of Earth
Is there a pattern???
YES!!!

14. Continental Drift How is this possible?
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
Define each term. Have the students as a class mimic the movement of divergent, convergent, and transform boundaries using their hands. Use the hyperlinks as visuals while discussing each type of plate boundary.

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 Surface 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. Earthquakes in the US: OTHER FAULT LINES
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?

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

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

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

36. Mount Vesuvius

37. Mount St. Helens