Introduction


 * Science Earth**



**Introduction**

 * Before you begin this activity view the video on Plate Tectonics below**

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The earth never seems to change, but it does, constantly. Volcanoes rumble and erupt. Earthquakes rattle and roll, reminding us of that our planet is in a constant state of change and movement. The crust, or the solid shell of the earth is about 25 miles thick over the continents, and about 4 miles thick under the ocean floors. The crust of the earth is thought to be made of semi-rigid plates that float on the pressurized mantle of the earth. The movement of the plates is considered as the Plate Tectonic Theory. Almost all of the processes that shape our Earth are effected by what is going on deep under the crust. Some scientist believe that life would not be possible on Earth if it were not for the activity going on miles beneath our feet. Tectonic plates movement plays a vital role in this process. Essential Questions: 1. Where are Earth’s tectonic plates and their boundaries? 2. How have plate movements cused changes in the positions and shapes of Earth’s landmasses? 3. How and where do volcanoes form? 4. How and where do earthquakes occur? 5. How do scientists locate and measure earthquakes?