Plate Tectonics

1. Plate Tectonics How our Earth changes By Rachel Williams

2. Questions? • What makes plates move? • Why do earthquakes happen? • How hot is lava? • Is there a need for earthquakes?

3. Inside Earth There are three basic parts to our earth that vary in size, composition, temperature and pressure Crust: Outer skin is a solid layer of rock that contains both dry land and ocean floor. Like the skin of an orange Mantle: Rock that is hot but solid and can slowly move Core: Liquid outer core and solid inner core and is mostly metal. Lava is 1,292⁰F-2,282⁰F. That is really hot. The Earth grows hotter and hotter as it goes farther into the Earth

4. Alfred Wegener: Theory of why our earth looks like it does today---Crust Pieces Move Alfred Wegener was the originator of the drift theory (1910). He also was the one who figured out that freshwater dinosaur fossils were found in spots across the country . The thing is the sections are separated by salt oceans. That means that since the dinosaurs could not cross the water the land had to be connected at their time. He was the one that figured out that plates move over time.

5. Pangaea Way before civilization, there was a super continent called Pangea. A super continent is a huge mass of land. The slowly moving mass has, over millions of years, moved our continents to their current location today.

6. Pangaea 200 million years ago the plates moved, and North America, Europe, and Asia, broke away. Together they formed Laurasia. Africa, South America, Australia, and Antarctica together formed Gondwanaland.

7. Currents in Solid Rock The reason that the plates moved is the currents . The currents take place in our mantle. Hotter rock rises(lower density) closer to the surface of the Earth. It cools, and sinks. This creates a endless cycle of currents in the mantle. This is what slowly makes the plates move.

8. Plates (Crust pieces that are moving) There are 20 plates in the world. They float on the mantle, moving 1-8 inches a year. The plates interact with each other in three ways. They either diverge, converge, or slip past.

9. Converging When ocean plates converge, older, denser plates slide underneath the new ones. Continental plates converge when huge cliffs form from plates slipping under each other. When one side of the plate is diverging the other is converging. This means the plates are being smashed against each other. They can either slip, or form a mountain. When the plates push together, they form a mountain. This is also known as converging.

10. Diverging Ocean plates can and continental plates diverge. While one edge of the plate is converging, the other side is diverging, or pulling apart. When it pulls apart, new magma comes and fills the gap, making new sea floor. When continental plates diverge, it creates a rift valley. A rift valley is a canyon of rock.

11. Earthquakes Earthquakes result from the plates moving against each other. The movement of the plates forming the earthquake is also known as a slip past. Sometimes the plates get stuck, and when released the energy is in the form of a earthquake. Shock waves are the vibration after a earthquake. Measured by the Richter scale for power and Mercalli scale for effect. There are different types of earthquakes. Surface waves travel only through the crust. Body waves travel through the earth itself.

12. Faults A fault is a crack between the plates that the plate slides along.

13. Bibliography Farodon, John. How the Earth Works, 1992 Nemeth, Jason. Plate Tectonics, 2012 Simon, Seymour. Earthquakes, 1991 Steele, Philip. Rocking and Rolling,1997. Stille, Darlene. Plate Tectonics, 2007 picture source list: http://www.enchantedlearning.com/subjects/astronomy/activities/radiobuttshtml https://en.wikipedia.org/wiki/Pangaea http://www.moorlandschool.co.uk/earth/tectonic.htm http://dreamatico.com/mountain.html https://www.pexels.com/search/earth/ https://www.pexels.com/search/earth/ http://www.alan.com/wp-content/uploads/2014/07/FrackQuake.jpg