Unit 2 Measuring the Earth

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Unit 2 Measuring the Earth

• Regents Earth Science
• Mr. Evans

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Earths Structure and the Shape of the Earth

• Agenda
• Discuss Earths layered structure
• Why does this structure exist?
• Draw a diagram of Earths Layers
• Begin using p. 10 ESRT
• Inferred Properties of Earths Interior
• Discuss the Spheres of the Earth System
• Learn About and Discuss the true shape of the
  Earth

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Earths Structure
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Drawing of the Layers of the Earth
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Crust

• the outermost layer of the solid Earth
• It is approximately 10 km thick beneath the
  oceans and approximately 65 km thick beneath the
  continents.

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Mantle

• the plastic layer beneath the crust
• It is approximately 2850 km thick.
• What does plastic mean?

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Outer Core

• the molten layer below the mantle and above the
  core
• It is approximately 2100 km thick.
• How can we tell that it is molten?

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Inner Core

• the solid center layer of the Earth.
• The radius of the inner core is approximately
  1400 km thick.
• How can we tell that it is solid?

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Watch the Animation in this Video Clip
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Four Spheres of the Earth System

• Lithosphere
• Hydrosphere
• Atmosphere
• Biosphere Living Environment

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Lithosphere

• the rock layer at the surface of the Earth that
  forms a thin shell-like layer that surrounds our
  planet.
• Lithos means rock

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Hydrosphere

• the thin layer of water resting on the
  lithosphere.
• Covers approximately 70 of Earths surface
• Average thickness lt 4 km
• Hydro means water

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Atmosphere

• the thin shell of gases that surrounds the Earth
  and is held in place by gravity.
• The atmosphere is several hundred km thick.

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The Shape of The Earth

• The shape of the Earth is an oblate spheroid, not
  a perfect sphere, because it is slightly
  flattened at the poles and bulged at the equator.
• This is the shape that all rotating spheres take.

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Oblate Spheroid