Chapter 7 Section 1

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Chapter 7 Section 1

• Inside the Earth

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Compositional Layers of the Earth
(Brown)
(Gray/green)
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Composition of the Earth

• The Earth is divided into 3 compositional layers
• Core
• iron, nickel
• Mantle
• magnesium, iron, aluminum, silicon, oxygen
• Crust
• oxygen, silicon, aluminum, iron, calcium,
  magnesium
• Crust and mantle are not very dense.
• Core is denser than the crust mantle.

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Compositional layers of Earth
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CRUST

• The outermost layer
• 5-100 km thick
• Thinnest layer
• 2 types of crust
• Continental- thick
• Oceanic-thin

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MANTLE

• 2900 km thick
• Layer between the crust and core
• Thicker than crust
• Contains most of Earths mass
• Scientists study the mantle by looking at the
  composition of magma.
• Magma from volcanoes gives scientists clues about
  the composition of the mantle.

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How scientists see the mantle

• Volcanic eruption of Mt. Etna in Sicily

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CORE

• Innermost layer, below mantle to center of Earth
• Made mostly of iron and nickel
• Divided into two parts
• Inner coresolid
• Outer coreliquid

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Physical Properties of Earth How the layers
respond to heat and pressure

• Earth divided into 5 physical (mechanical)
  layers
• Lithosphere
• Asthenosphere
• Mesosphere
• Outer Core
• Inner Core

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Lithosphere

• Outer layer of Earth
• Made of crust rigid, upper mantle
  (asthenosphere)
• Divided into pieces called tectonic, or
  continental plates
• Continental plates drift slowlya few centimeters
  a yearon top of the mantle

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Asthenosphere

• Layer below lithosphere
• Pieces of lithosphere (tectonic plates) move
  along this layer
• Made of solid rock, soft, plastic-like layer of
  the mantle

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Mesosphere

• Below the asthenosphere
• Strong lower part of mantle
• Extends to the Earths core

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Outer Core

• Liquid layer of Earths core
• Surrounds inner core

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Inner Core

• Solid dense center

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Quiz

• 1. What are the three compositional layers of
  the Earth?
• 2. What are the physical layers of the Earth?
• 3. Is the mantle solid or liquid?
• 4. What physical and compositional layers of the
  Earth do you live on?

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Quiz Answers

• 1. What are the three compositional layers of
  the Earth? Crust, Mantle, and Core (CMC)
• 2. What are the physical layers of the Earth?
• Lithosphere, Asthenosphere, Mesosphere, Outer
  Core, and Inner Core
• 3. Is the mantle solid or liquid? Liquid that
  can be forced to act as a solid
• 4. What physical and compositional layers of the
  Earth do you live on?
• Physical lithosphere Compositional Crust