Earths Layers


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Earths Layers

  1. 1. Earth Layers <ul><li>The Earth is divided into four main layers. </li></ul><ul><ul><li>*Inner Core </li></ul></ul><ul><ul><li>*Outer Core </li></ul></ul><ul><ul><li>*Mantle </li></ul></ul><ul><ul><li>*Crust </li></ul></ul>
  2. 2. The Earth’s Crust <ul><li>The crust is the thinnest layer on Earth, 5 km to 100 km </li></ul><ul><li>There are two types of crust </li></ul><ul><ul><ul><li>Oceanic crust – made mostly of the igneous rock basalt. Found under the ocean. Relatively thin, </li></ul></ul></ul><ul><ul><ul><li>5 km to 7 km. Contains more iron than the Continental crust, therefore is more dense. </li></ul></ul></ul><ul><ul><ul><li>Continental crust – made mostly of granite. Found under the continents. Relatively thick, up to 100 km. </li></ul></ul></ul>
  3. 3. Special parts of the Crust <ul><li>Lithosphere </li></ul><ul><ul><li>Crust is the upper part of the lithosphere. </li></ul></ul><ul><ul><li>Broken up into large plates. </li></ul></ul><ul><ul><li>The uppermost part of the mantle is also part of the Lithosphere </li></ul></ul><ul><li>Asthenosphere </li></ul><ul><ul><li>Upper part of mantle, below lithosphere </li></ul></ul><ul><ul><li>130 – 160 km thick </li></ul></ul><ul><ul><li>Cooler part of the mantle that the lithosphere plates slide on top of. </li></ul></ul>
  4. 6. The Earth’s Mantle <ul><li>Located directly above the outer core </li></ul><ul><li>Starts below the crust </li></ul><ul><li>Is the largest layer </li></ul><ul><li>80% of the Earth’s volume & 68% of Earth’s mass </li></ul>
  5. 7. The Earth’s Mantle <ul><li>Composed of more iron than the crust. </li></ul><ul><li>Density, pressure, and temperature all increase the deeper you go in the mantle </li></ul><ul><li>Temperature ranges from 870 C – 2200 C </li></ul>
  6. 9. Special layers of the mantle <ul><li>Lithosphere – crust plus the upper, solid part of the mantle. Forms plates. </li></ul><ul><li>Asthenosphere – just under the lithosphere. Slow moving “Silly putty” layer on which the lithospheric plates slide. (Solid rock that flows very slowly.) </li></ul>
  7. 11. The Earth’s Core <ul><li>The Earth’s Core </li></ul><ul><li>Composed of the inner and outer core </li></ul><ul><li>Both are made of iron and nickel </li></ul>
  8. 12. The Earth’s Outer Core <ul><li>The Outer Core - Liquid </li></ul><ul><li>Surrounds the inner core </li></ul><ul><li>Temperature ranges from 2200 C – 5000 C near inner core </li></ul><ul><li>Molten (liquid) iron and nickel </li></ul>
  9. 14. The Earth’s Inner Core <ul><li>The Inner Core - Solid </li></ul><ul><li>Temperature reaches 5000 C </li></ul><ul><li>Solid iron and nickel </li></ul><ul><ul><li>Usually both would be liquid but are solid in the core because of the incredible pressure </li></ul></ul><ul><li>The solid core is the source of Earth’s magnetic field </li></ul>
  10. 15. Magnetosphere <ul><li>The inner core and outer cores do not turn at the same speed as the rest of the earth. </li></ul><ul><li>Causes a generator effect which produces a magnetic field. </li></ul><ul><li>It protects us from some of the sun’s harmful radiation. </li></ul>
  11. 17. <ul><li>What does the inside of the Earth look like? </li></ul><ul><li>How do scientists know that there is a solid inner core? </li></ul>
  12. 18. <ul><li>Determining the composition of the Earth </li></ul><ul><li>Scientists cannot see the interior of the planet, or drill to the core, so they use seismic waves to determine the composition of the layers. </li></ul><ul><li>Seismic waves: are vibrations that are produced when an earthquake happens. </li></ul><ul><li>Seismic waves travel at different speed depending on the composition and density of material. Measuring these waves tells us what is in the Earth’s layers, and how the materials change. </li></ul>
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  14. 20. What do you know about these layers?