SPHERES OF THE EARTH

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SPHERES OF THE EARTH
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What Do We Already Know?

• Imagine that you are drilling a hole to the
  center of the earth. What do you think you would
  see on this journey?
• The Core/Journey to the Center of the Earth

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Earths Layers

• Earth has four layers
• Crust the thin crust is the surface layer of
  the Earth and made of rock.
• Mantle the wide layer beneath the crust that is
  made mostly of solid rock or some soft rock.
  (Upper and lower mantle)
• Outer Core made of liquid iron
• Inner Core made of iron and nickel, but it
  remains solid because of intense pressure.

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Layers of the Earth
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Plates

• Earths crust and upper mantle are divided into
  sections called plates. Plates are blocks of
  crust and upper mantle rock that fit together
  like puzzle pieces.
• Plates float on the soft rock of the mantle. As
  this rock flows, it causes the plates to move.

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Model of Plate Movement

• Plates can move in three ways
• Push together
• Pull apart
• Slide past
• Place two textbooks next to each other on your
  table and model the three different ways that
  plates can move.

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Earthquakes

• An earthquake is movement of the ground caused by
  a sudden release of energy in Earths crust.
• Sandpaper Insta-Lab

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More Earthquake Terminology

• The focus is the place within the crust where
  energy is released during an earthquake. The
  epicenter is the point on the surface of the
  Earth directly above the focus and is where the
  most damage is likely to occur.
• Most earthquakes occur along a fault, or a break
  in Earths crust.

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The San Andreas Fault
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How Do Scientist Measure Earthquakes?

• Scientists use seismographs to measure the
  magnitude of earthquakes.
• Magnitude, or the amount of energy released, is
  reported using the Richter Scale.
• Seismograph Model

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Volcanoes

• A volcano is a mountain made of lava, ash, or
  other materials from eruptions.
• Magma is melted or molten rock found beneath the
  surface of the Earth.
• Lava is magma that reaches the Earths surface.

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How Do Mountains Form?

• Mountains are the tallest landforms on Earth .
• They form when
• plates come together and part of the crust is
  forced up.
• Pressure is applied to the edges of a plate and
  rock in the middle is forced upward.
• When plates pull apart and magma fills in the gap
  forming volcanoes.

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Reading Review

• What causes Earths plates to move?
• What causes an earthquake?
• How do mountains form?
• Which layer of the Earth are we standing on?