Processes that change Earth

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Processes that change Earths surface

• Mr. Mathews
• 6th Grade Science

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Essential Question

• 1.) How do temperature, pressure/density, and
  composition vary as you descend through each
  layer of the inside of the earth?
• 2.) How are Earths layers alike and different?

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I. Earths Interior

• A. Geologist Geology
• -Study forces that make shape Earth
• B. Surface Changes (two forces)
• 1. Constructive Forces - shape surface by
  building up mtns landmasses
• 2. Destructive Forces slowly wear away
  mtns and other features

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Constructive Force
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Destructive Force
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I. Earths Interior

• C. Journey to Center of Earth
• 1. Temperature - Closer to center of Earth,
  hotter it gets.
• 2. Pressure force pushing on a surface
  area. Increases closer to center of Earth.
• 3. Composition stuff something is made of.
  Changes within each layer of earth.
• 4. Density amount of stuff in given space.
  Increases as you get closer to center of Earth.

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I. Earths Interior

• D. 3 Main Layers of Earth
• 1. Crust forms outer skin 2 types
• -made up mainly of basalt and granite (types
  
• of rock)
• - 5 -100 km thick
• a. Continental Crust mainly granite rock and
  has the elements oxygen, silicon, and
  aluminum.
• b. Oceanic Crust mainly basalt rock and has
  the elements iron, calcium, and
  magnesium.
• Solid or Liquid?
• Solid!

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Layers of Earth
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Density of the Crust

• Continental Crust 2.7 g/cm3
• Oceanic Crust 3 g/cm3

2.7g
3g
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I. Earths Interior

• D. 3 Main Layers of Earth
• 2. Mantle layer of hot rock 2,900 km thick
  composed
• of magnesium, aluminum and silicon
• 3 sub layers
• a. lithosphere Uppermost part of mantle
  and crust together, lithos means stone,
  approx. 15 - 300 km thick
• b. asthenosphere soft layer of mantle under
  lithosphere, asthenes means weak, soft
  but can flow, maybe like thick syrup. Approx
  250 km thick
• c. mesosphere layer between asthenosphere
  and outer core, meso means middle. Approx
  2,550 km thick.

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Layers of Earth
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Density of the Mantle

• Mantle 3.4 g/cm3 - 5.4 g/cm3

5.4g
to
3.4g
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I. Earths Interior

• D. 3 Main Layers of Earth
• 3. Core 2 Parts 3,500 km thick, about
  size of moon. Made mostly of iron and nickel.
• a. outer core melted metal
  surrounding inner core
• b. inner core thick ball of solid metal

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Layers of Earth
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Density of the Core

• Outer Core 10g/cm³ - 12.3g/cm³
• Inner Core 15g/cm³

10g
to
12.3g
15g
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I. Earths Interior

• E. Earths Magnetic Field
• -Inner core spins faster than Earth creating
  magnetic field.
• Earth is like a huge magnet!

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Explain how you are like this shpere

• Example I am like the mesosphere because I am
  the middle child (middle layer) and I am a very
  strong person that can handle most situations.

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II. Convection Currents and the Mantle

• Heat Moves!
• -Heat Transfer movement of energy (heat) from a
  warmer object to a cooler object.

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II. Convection Currents and the Mantle (continued)

• 3 types of heat transfer
• 1. Radiation transfer of energy (heat)
  through empty space.
• -no contact required
• ex. Sunlight
• Heat from a fire

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Radiation
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II. Convection Currents and the Mantle (continued)

• 2. Conduction heat transfer by direct
• contact of particles of matter
• ex. A spoon in a hot pot.
• A pot on a hot stove

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Conduction
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Convection Currents and the Mantle (continued)

• 3. Convection Heat transfer by movement
• of heated fluid.
• a. density measure of mass in a
  
• volume of substance.

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Convection
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3 Types of Heat Transfer
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Density

• Cool fluid is more dense than hot fluid
• Hot fluids tends to rise and cool fluids tends to
  sink.
• As temperature increases, density decreases and
  the opposite is true.

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Convection Currents (cc) and the Mantle
(continued)

• B. convection current (cc) flow that
  transfers heat within a fluid.
• 1. heating and cooling of fluid, changes
  in density, and force of gravity cause
  convection currents (cc).
• - (CC) occur within the asthenosphere
  creating movement

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Convection Currents (cc) and the Mantle
(continued)
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III. Sea-Floor Spreading

• -Continental Drift idea that continents
  slowly move over Earths surface
• Video clip

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III. Sea-Floor Spreading

• Mid-ocean Ridge underwater mountain/volcano
  range.
• 1. Molten (melted) rock rises from mantle and
  erupts. It spreads out, pushing older rock to
  both sides of ridge.
• 2. Sea-floor spreading process of adding
  new material to ocean floor.
• Video clip

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III. Sea-Floor Spreading

• B. Deep-ocean trenches deep underwater
  canyons where ocean crust bends downward.

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Deep-Ocean Trenches
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III. Sea-Floor Spreading

• C. Subduction process of ocean floor sinking
  into
• trench and back into mantle

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Ocean Floors and Plate Tectonics
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IV. The Theory of Plate Tectonics

• A. Theory of Plate Tectonics
• 1. Tectonic Plate broken pieces of
  crust/lithosphere
• 2. Scientific Theory well-tested concept
  explaining wide range of observations.

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IV. The Theory of Plate Tectonics

• 3. Plate Tectonics theory that states pieces of
  
• crust/lithosphere in constant, slow motion
  b/c
• of convection currents in asthenosphere.
• a.This theory explains formation, movement, and
  subduction of Earths plates.
• Video clip

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IV. The Theory of Plate Tectonics

• B. Plate Boundaries (3 types)

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What is a boundary?

• The place where two plates meet.

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IV. The Theory of Plate Tectonics

• Transform 2 plates slip past each other
  in opposite direction
• -crust is neither created or destroyed

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IV. The Theory of Plate Tectonics

• 2. Divergent 2 plates move apart, or diverge
• -most occur at mid-ocean ridge

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IV. The Theory of Plate Tectonics

• 2. Divergent (continued)
• a. Rift Valley when divergent boundary
  occurs on land

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IV. The Theory of Plate Tectonics

• 3. Convergent 2 plates come together, or
  converge
• -subduction occurs or mountains are formed.

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