1. Plate Tectonics Liz LaRosa for use with my 5 th Grade Science Class http://www.middleschoolscience.com 2009 http://www.middleschoolscience.com

2. Earth’s Layers The Earth's rocky outer crust solidified billions of years ago, soon after the Earth formed. This crust is not a solid shell; it is broken up into huge, thick plates that move atop the soft, underlying mantle.

3. Stop and Answer! 1.What are the 4 layers of the earth? 2.Put them in order from the outermost layer to the innermost layer (from the outside to the center).

4. Plate Tectonics The plates are pieces of the lithosphere that move around. Think About This: Imagine you have a balloon. You cover the outside of it in a layer of toothpaste. Then you get a piece of paper and slide it around the surface of the balloon. This is similar to how the continents (land) moves around the Earth. Think of the mantle as the toothpaste and the crust as the paper.

5. Each plate has a name. They have drifted around the Earth’s crust, but if you put them together, they would fit like puzzle pieces.

6. Continental Drift Alfred Wegener hypothesized in the 1900’s that continents were once a single land mass that drifted apart. Fossils of the same plants and animals are found on different continents, providing evidence (supportive data or proof) of the fact that all of the continents may have once been one big continent!

7. He called this supercontinent Pangea, a Greek word for “all Earth,” and said it probably existed about 245 Million years ago.

8. Evidence of Pangea: Look at all of the places that the same fossils have been found!

9. Stop and Answer! 1.Why might finding the same fossils of the same animals in different continents be proof that the continents used to be part of the same land mass? Explain your answer in complete thoughts and complete sentences.

10. How do the plates move? How do the plates move? ***Write this down!*** Earth’s mantle transfers heat through convection currents which make the plates move. Remember! Convection is when heat energy is transferred in a fluid. Warm objects or locations move to cooler objects or locations in circular patterns.

11. The mantle is made up of solids and liquids. The top part of the mantle, near the crust is cooler. What happens to cooler particles? They get more dense (closer together). Dense objects sink through less dense objects. (Remember, that’s why icebergs float) The rocks closer to the core are melted. They have more energy, so the spread farther apart and float to the top. The mantle is constantly moving in convection currents.

12. What happens when the plates move?

13. Earthquakes!!

14. What causes earthquakes? Tectonic plates move past each other causing stress. Stress causes the rock to deform.

15. Stress Sometimes the rocks in the plates stick together. As the plates continue to move, the rocks get stressed. When the rocks break free, the stress is released in a big shake that we feel as an earthquake.

16. Earthquakes ***Write this down!*** Earthquakes are a sudden shaking of the ground caused by the movement of plates. Earthquakes occur along faults. –Faults are cracks in the crust where plates move past each other. San Francisco Earthquake 1910

17. Types of Faults Along the boundary separating any two plates, the relative motion between the plates can be classified into one of 3 categories Divergent: Pulling Convergent: Pushing Transform: Sliding

18. Stop and Answer! Imagine that you live on a fault line. One day, there is a huge earthquake! You step outside and find that the swing set that used to be in your backyard is now 20 feet away in your neighbor’s yard. 1.What kind of fault line do you probably live on? (You can use the slide before this for reference.) Explain your reasoning.

19. Divergent Boundary – when two tectonic plates move away from each other. Arabian and African Plates are on a divergent boundary. When this happens often bodies of water form, because water fills in the area where land used to be.

20. Convergent Boundary – when two tectonic plates move toward each other. The Indian and Eurasian Plates are on a convergent boundary..

21. Time to investigate! 1.Logon to Discovery Education.Discovery Education 2.Click on the assignment that says “Tectonic Forces” 3.Click “Start Here” at the bottom of the screen and listen to the information. Then, close out that window. 4.Click a boundary from the box that says “Choose a type of boundary” at the top of the screen. 5.Click the white circles to see what kind of tectonic activity and geographic features go together. 6.Read the background information by clicking the “Background” tab at the bottom of the screen. 7.Answer the questions from the “Questions” tab in your notebook.