Section 1: Earth

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Section 1 Earths InteriorWho Studies Earths
Interior?

• Geologists
• Scientists who study the forces that make and
  shape planet Earth.
• They study the processes that create Earths
  features and search for clues about Earths
  history.

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What kind of evidence do scientists use to learn
about the interior of the earth?

• Direct vs. Indirect
• Direct evidence from rock samples. Scientists
  drill up to 12 km into the earth. Forces blast
  rock from as deep as 100 km.
• Indirect evidence from seismic waves

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How do scientists study the Earth?

• To reach the Earths core you would have to
  travel over 6,000 km (3,728 miles)!
• Scientists record Seismic Waves a vibration
  that travels through Earth carrying the energy
  released during an earthquake
• Types of seismic waves
• P waves travel through crust (6km/sec) and
  mantle (8km/sec)
• S waves will not travel through liquid
• http//aspire.cosmic-ray.org/labs/seismic/seismic.
  swf

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What is the Earths structure?

• The Crust
• The Mantle
• Lithosphere
• Asthenosphere
• The Core
• Outer Core
• Inner Core

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What is the structure of the crust?

• A layer of rock that forms the Earths outer skin
  including the rock under the ocean
• Two types of crust
• Continental Crust
• Granite less dense crust
• Oceanic Crust
• Basalt more dense rock

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What is the structure of the mantle?

• Two major parts
• Lithosphere upper part of crust and mantle
  together floats on top of the asthenosphere
• Asthenosphere softer than the mantle due to
  increasing temperature and pressure
• The mantle is nearly 3,000 kilometers thick!
  (1,864 miles)

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What is the structure of the core?

• Two parts
• Outer Core liquid behaves like a thick liquid
  forces the solid inner core to spin causing
  Earths magnetic field
• Inner Core solid extreme pressure squeezes the
  atoms of iron and nickel so that they cannot
  spread out to become liquid
• Inner core and outer core are just slightly
  smaller than the moon

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Chemical Layers
Physical Layers
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Section 2 Convection and the Mantle How does
Heat transfer?

• Radiation heat transfer through empty space
  ex. sunlight
• Conduction heat transfer through direct contact
• Convection- heat transfer by movement of heated
  fluids

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How do convection currents affect the Earth?

• Heating and cooling a fluid changes its density
  warmer fluids have a lower density and float
  colder fluids have a higher density and sink

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Section 3 Drifting ContinentsWere the
continents once together?

• Alfred Wegener hypothesized that all the
  continents had moved from a supercontinent known
  as Pangaea.

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What is the evidence for Wegeners idea?

• Evidence of Continental Drift
• Landforms similar mountain ranges
• Fossils similar fossils of a fernlike plant
  existed on both continents
• Climate tropical pl ant fossils found in cold
  climates

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Section 4 Sea-Floor SpreadingWhat is happening
in the ocean?

• Using sonar scientists discovered mountains under
  the ocean
• The longest chain of mountains in the world is
  under the ocean and is known as the Mid- Ocean
  ridge!

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Side-scan sonar image of the remains of the
submarine USS O-9 (SS-70) off the Isle of Shoals,
New Hampshire in more than 400 feet of
water.Courtesy of NOAA.
Side-scan sonar locates missing planeCourtesy of
NOAA.
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What is sea-floor spreading?

• Harry Hess suggested that at the mid-ocean ridge
  molten material rises from the mantle and erupts
  pushing older rock to both sides
• This process is known as sea-floor spreading!

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What is the evidence for Sea-floor spreading?

• Evidence from Molten Material
• Evidence from Magnetic Strips
• Evidence from Drilling Samples

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How can the ocean floor keep from getting wider
and wider?

• The older ocean floor plunges into deep-ocean
  trenches in a process known as subduction
• Sea-floor spreading and subduction work together
  like a giant conveyer belt!

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Section 5 What is the theory of plate tectonics?

• The Earths lithosphere is cracked into separate
  sections known as plates
• Geological theory states that these plates are in
  constant, slow motion, driven by the convection
  currents in the mantle

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How is the theory of plate tectonics different
from continental drift?

• Continental drift is based on the movement of the
  continents DUE to plate tectonics
• Continents are NOT the same as plates
• Tectonic plates can be made up of both oceanic
  crust and continental crust

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What happens where the plates meet?

• Plate Boundaries where the edges of the
  lithosphere meet faults form along these
  boundaries
• Transform
• Divergent
• Convergent

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What are Transform boundaries?

• The place where two plates slip past each other,
  moving in opposite directions
• Earthquakes occur frequently at these boundaries

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What are Divergent Boundaries?

• The place where two plates move apart, or diverge
  and create a rift valley
• Most occur at the mid-ocean ridge although some
  can occur on land

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What are Convergent boundaries?

• The place where two plates come together, or
  converge creating a collision
• Subduction occurs at convergent boundaries
• The density of the crust determines which crust
  will be on top if both plates are the same
  density they form a mountain range