The Geosphere

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The Geosphere

• Earths Internal and External Structure

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How do we know about the Earths Interior?

• Two main types of evidence
• Direct evidence from rock samples
• Have drilled holes as deep as 12.3 kilometers
  into earth and bring up rock samples
• Indirect evidence from seismic waves
• Earthquakes produce seismic waves, geologists
  record seismic waves and study how they travel
  through the earth

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Layers by compositionUse the hand out to refer
to as we go over the notes

• Crust Mantle Inner and Outer Core

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Using the questioning cards

• Write, on a sticky note, a statement about the
  layers of the Earth, that can be answered using
  one of the words from the talking bubble side
  of the card.

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Crust

• A thin, rocky layer
• Made by volcanic activity
• Continental Crust- low density, not compacted
• Oceanic Crust-Heavy, compacted rock and thinnest
  part of crust

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Mantle

• iron, magnesium, silicon, and oxygen.
• 82 of Earths volume
• Rock that is very hot but solid

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• Outer core molten flow of metals within the
  outer core generates the earths magnetic field.
  Mostly iron and nickel
• Inner core compressed into a solid state by
  extremely high temperature

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Layers defined by physical properties

• Lithosphere
• Asthenosphere
• Mesosphere

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Lithospere

• crust and the upper, solid
• 5 30 miles deep
• Cool rigid shell
•  The plates that move about Earth's surface
  include the entire lithosphere, not simply the
  crust.

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Asthenosphere

• Plastic-like soft, weak rock layer of the mantle
• mostly solid but close enough to melting that it
  is easily deformed.
• Flows by mantle convection current.

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Mesosphere

• More rigid
• Lower mantle
• Pressure makes rocks strong, but high temperature
  causes some flow.

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Overview of the layers

• The layers vary greatly in size, composition,
  temperature and pressure.
• The deeper down in the Earth, the greater the
  pressure.
• Temperature increases as depth increases

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What's next

• Now with your group look at your lab sheet. You
  have till the end of class to complete this
  project. You must call me over to take a picture
  of it when you finish for a grade.
• All supplies MUST be back in your group box the
  way you found them when the bell rings!
• If you finish early work on your homework.