Journal

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Journal

• Imagine that you were asked to create a model of
  Earth today
• What would your model show?

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2. 1 Earth A Unique Planet
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Zones of Earth

• Crust
• Mantle
• Core

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Characteristics of the 3 major zones of Earth

• 1. Crust
• Thin outermost zone
• 1 of Earths mass
• Continental Oceanic crust
• 2. Mantle
• Zone of rock
• 2/3 of Earths mass
• 2 different regions lithosphere (solid upper
  region) asthenosphere (plastic - flows)
• PLASTICITY ability of a solid to flow
• 3. Core
• Center of Earth
• Composed of Iron
• Solid Inner core, Liquid Outer Core

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Pause Observation of Plasticity
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Review Zones of Earth
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How did scientists learn about the layers of
Earth?

• 1. Seismic Waves
• 2. Reconstruction of changes in Earths surface
  and magnetic field

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Seismic Waves

• Vibrations that travel through Earth
• What causes seismic waves?
• Earthquakes
• Explosions
• Volcanoes
• Landslides

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Two Types of Seismic Waves

• P Waves
• Primary waves
• Travel through solids, liquids, and gasses
• S Waves
• Secondary Waves
• Travel only through solids
• Speed and direction of seismic waves reveals the
• composition of Earths Interior

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• Moho Boundary between crust and mantle
• Shadow Zones Areas where waves are not detected
  or only P waves are observed.
• Caused by materials that have different
  rigidities
• Waves bend and change direction

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• Because seismic waves bend and change direction,
  looking at how the waves travel from one side of
  the world to the other, scientists are able to
  deduce the properties of Earths Interior!!!
• (Math is useful!!!)

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The Earth as a Magnet

• Earth has 2 magnetic poles
• Magnetosphere region of space that is affected
  by Earths magnetic field
• Source of magnetic field- possibly the iron core
  of Earth

? Next time We will discuss the changes in the
magnetic poles of earth as another clue about
Earths interior and the processes that drive
change on Earth
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Gravity

• The force of attraction that exists between ALL
  matter in the universe!
• Journal
• Are you composed of matter?
• Do you exhibit a gravitational pull on objects
  around you????

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Law of Gravitation

• The force of attraction between any two objects
  depends upon their masses and the distance
  between them.
• Journal
• How does the moons gravitational pull influence
  Earth?

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THE END

• Start our Model of Earth !!!!