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Plate Tectonics. A lesson designed for 5th graders By: Meri Koski. The theory of plate tectonics is only about 30 years old. It states that the outer layer of Earth (the lithosphere) is broken into 7 plates that move in all different directions and at varying speeds (2-10cm per year).
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Plate Tectonics A lesson designed for 5th graders By: Meri Koski
The theory of plate tectonics is only about 30 years old. It states that the outer layer of Earth (the lithosphere) is broken into 7 plates that move in all different directions and at varying speeds (2-10cm per year). The movement of these plates explains to us natural disasters such as volcanoes and earthquakes, worldwide distribution of plant and animal fossils, and the movement of the mantle (the layer below Earth’s crust).
Where two plates meet, it is called a boundary. There are three different types of boundaries that describe how the plates are moving. • ConvergentBoundaries: plates collide • DivergentBoundaries: plates move apart • Transform Boundaries: plates move against each other
Convergent Boundaries • Plates crash together. • Continental plate is pushed up and forms mountains. • Oceanic plate sinks below continental plate and becomes part of the mantle. • Earthquakes occur due to the collision of plates. • Melting oceanic plate and mantle rise up into the mountain creating a volcano • The Himalayan and Appalachian mountains are results of plates colliding.
Divergent Boundaries • Plates are drifting apart. • A rift valley forms, which is a deep crack in the crust. • As plates move apart, magma comes up and forms a new crust. • The Mid-Atlantic ridge (the largest mountain range) was formed this way and is still growing.
Transform Boundaries • Plates slip & slide • The San Andreas Fault is one of the most famous transform boundaries • No mountains or spectacular features form along this boundary. • Tension builds between two plates and releases. • An earthquake is usually the result of these plates moving.
Our Earth then and now • About 200 million years ago the land masses on Earth were fused together. This single continent is known as Pangaea. • Due to the movement of the mantle (under the crust), Pangaea has formed into the Earth we know today.
Evidence that Pangaea did exist • Fossils are the main form of evidence that our continents were once fused. • Similarities between plant and animal fossils have been found on land masses that are very far apart today (such as Africa and S. America). • For example: dinosaur fossils and footprints have been found in many places around the world. If the land masses were separated like they are now, how did they get across the oceans?
This picture illustrates different dinosaurs and plants that have been found all over the world. • This was possible because of Pangaea!
Web sites to learn more! Check out these web sites to learn more about plate tectonics. Interactive Plate Tectonic Site Plate Tectonics
Test your knowledge Now that you have learned about the theory of plate tectonics, you can test what you know! Plate Tectonic Quiz – 10 question, multiple choice quiz on PowerPoint. Answers To Quiz – Check how much you really know.