Layers of the Earth

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Layers of the Earth
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The Earths Interior

• Most scientists agree that soon after Earths
  formation, Earth was a large ball of molten
  (melted) rock. As time passed, the molten
  materials cooled, hardened, and separated into
  layers.

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Composition (What it is made of)

• Crust
• Mantle
• Core

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The Crust

• Thin, outer layer that covers the planet
• 8 - 32 km thick
• 2 types of crust
• Oceanic (very dense, made of basalt)
• Continental (less dense, made of granite)

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Oceanic and Continental Crust
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The Mantle

• Middle layer
• Very thick layer
• (2900 km thick)
• Made of silicon, oxygen, iron, magnesium
• - solid that has the ability to flow plasticity

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The Core

• Central part of the planet
• Made of iron and nickel
• 1/3 of the earths mass
• Very hot
• - inner core solid
• - outer core liquid

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Earths Layers

• How are the earths layers similar to an egg?
• Shellcrust
• Egg whitemantle
• Yolkcore

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Physical Structure of the Earth(5 Layers)

• Lithosphere- rigid outer layer (crust)
• Asthenosphere- solid rock that flows slowly (like
  hot asphalt)
• Mesosphere- middle layer
• Outer Core- liquid layer
• Inner Core- solid, very dense

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Do scientists travel to the inside of Earth to
learn about the layers?

• High temperatures and tremendous pressure in the
  Earths interior would make traveling there and
  remaining alive impossible.
• Even the deepest oil wells are only a few
  kilometers deep, and the diameter of the Earth is
  12,756 km.

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So, how do we know about the layers?

• The study of behaviors of seismic waves has
  allowed geologists to piece together information
  about the parts of Earth that man has never seen
  directly.

When earthquakes occur, vibrations are sent out
through the Earth. These vibrations are called
seismic waves.
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Seismic Waves

• Seismic waves can travel along the surface of the
  Earth or through its interior.
• The waves speed up, slow down, or stop depending
  on the type of material (medium) that they are
  passing through.
• For example
• S-waves are a type of seismic wave that can't
  go through liquid. Therefore, scientists know
  that the part of the Earth that S-waves can't
  penetrate is made up of liquid.