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(OLD) Journey to the Center of the Earth

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Please don't use these slides to teach. Really. I only posted this as an example of how I used to (poorly) use PowerPoint. See the updated version here: http://www.slideshare.net/benwildeboer/journey-to-the-center-of-the-earth-265038

And see the explanation here: http://blog.benwildeboer.com/2008/as-promised-presentations-before-and-after/

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(OLD) Journey to the Center of the Earth

  1. 1. Journey to the Center of the Earth!
  2. 2. The Layers of the Earth • When the Earth first formed gravity pulled most of the heavy materials to the center of the Earth • Lighter materials “floated” to the surface of the Earth • As a result of gravity, the Earth separated into four main layers
  3. 3. The Crust • The thinnest layer of the Earth –On average it is: • 3 miles thick under the oceans • 19 miles thick under the continents
  4. 4. The Crust • There are two main types of crust: – Continental Crust • Thicker than oceanic crust – Up to 35 miles thick • Least dense layer in the Earth – Oceanic Crust • Much thinner than continental crust • Slightly more dense than continental crust
  5. 5. The Crust Nobody has ever drilled through the crust
  6. 6. Crust
  7. 7. The Mantle • Made up of heavier materials than the crust. • Slightly liquid – Similar to silly putty or play-dough • The largest layer in the Earth
  8. 8. The Mantle • Asthenosphere – A layer of the mantle just beneath the crust. • The asthenosphere is more fluid than the rest of the mantle.
  9. 9. The Mantle • Mohorovičić Discontinuity – Also known as: the border between the mantle and the crust. – Called the “Moho” for short – Named after Andrija Mohorovičić who located the border. http://www.earthscrust.org/earthscrus t/science/historic/img/mohorovicic.gif
  10. 10. Mantle Moho THICK LIQUID
  11. 11. Outer Core • Located 1,800 miles beneath the surface • Mainly made out of liquid iron and nickel – The liquid iron moving around in the outer core creates the Earth’s magnetic field.
  12. 12. Outer Core LIQUID (Iron & Nickel)
  13. 13. Inner Core • Located 3,200 miles beneath the surface • Made from solid iron and nickel • Very, very hot, but stays solid because the entire Earth is pushing down on the inner core.
  14. 14. Inner Core SOLID (Iron & Nickel)
  15. 15. Crust Mantle Moho Outer Core Inner Core
  16. 16. How Do We Know? • No one has even drilled through the crust, so how do we know what the layers are? – Earthquakes cause waves to go through the center of the Earth – Scientists use earthquake waves like a submarine uses SoNAR. • The waves bounce off the layers and tell scientists where a boundary is located
  17. 17. Heat in the Earth • The temperature in the center of the Earth gets up to about 10,000°F • Where does that heat come from?
  18. 18. Where Does the Earth’s Heat Come From? 1. Heat from when the Earth formed Comets & Meteors striking the Earth 2. Radioactive Elements in the Earth They decay and release huge amounts of heat. 3. Gravity pulling elements towards the center of the Earth Friction between materials rubbing against each other.