Motion and Newton

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Plate Tectonics and Layers of the Earth
Ch. 10 - p. 270 Earth Standards S6C1PO2, PO3,
PO4 S6C2 PO3, PO4, PO5
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Plate Tectonics Launch Lab!

• You will be working with the person sitting next
  to you.
• I will pass out a picture to you and your
  partner. Make sure no one other than the two of
  you sees which picture you received.
• You need to cut the picture up into 10-15 pieces.
  Make sure that each piece has a shaped edgeyou
  cannot just cut it into squares.
• Once you have cut your picture into pieces, trade
  with the other group at your table.
• Complete the puzzle using different strategies.
• Be ready to explain which strategies you used to
  solve the puzzle.

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New information About plate tectonics, Earthquake
s and volcanoes
What I think I know About plate Tectonics,
Earthquakes and Volcanoes
Facts (what I definitely know) about plate
tectonics, Earthquakes and volcanoes
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• Background Information Layers of the Earth
• The Earth is made up of several layers that have
  different properties and compositions.
• There are three main layers
• Crust
• Mantle
• Core (inner and outer)
• The lighter materials are the outermost layer,
  and the heavier materials are the inner, deeper
  layers.

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1) Crust - Outermost layer - Floats on top of
the mantle - Less than 1 of the Earths mass -
Ranges from 5 to 60 km thick thinnest
layer - We know most about this layer. Why? Two
types of crust on Earth Continental Crust -
Similar to granite - Between 20 60 km
thick Oceanic Crust - Similar to basalt more
dense than granite - Between 5 8 km
thick Both types of crust contain many tectonic
plates that float on top of mantle
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• 2) Mantle
• Layer between the crust and the core
• About 67 of the Earths mass
• 2,885 km thick
• No one has seen mantle layer too deep to drill
  to get sample
• Some places on Earth, mantle rock has been pushed
  through surface
• Molten rock from mantle layer flow from volcanoes
  on ocean floor
• Made up of mostly iron (Fe) and magnesium (Mg)
• Mantle contains 2 main layers
• Upper Mantle
• Base of crust to depth of 660 km
• Lower Mantle
• Depth of 660 km to 2225 km
• Crust and top of Upper Mantle together are called
  the Lithosphere
• About 100 km thick
• Contains area of earthquakes, mountain building,
  volcanoes and continental drift
• Just below Lithosphere is area called
  Asthenosphere
• About 100 200 km thick

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3) Core - About 33 of Earths mass - 6,972 km
in diameter - Made up of mostly iron (Fe) and
nickel (Ni) - Contains 2 layers - Inner Core
center of Earth - Solid - Outer Core -
Liquid - Surrounds Inner Core The planet
Mars is actually smaller than the core of
Earth (Mars 6,787 km)
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• Continental Drift
• hypothesis that states that the continents have
  moved slowly to their current locations on Earth
• In 1912, Arthur Wegener suggested that all the
  continents were connected as one land mass
• Large land mass of all the connected continents
  was called
• Pangaea all land
• Suggested Pangaea broke apart about 200 million
  years ago
• Hypothesis wasnt accepted until after Wegener
  died in 1930
• Puzzlelike fit of continents was Wegeners first
  evidence for Continental Drift

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Fossil Evidence of Continental Drift - Fossils
from the reptile Mesosaurus were found in South
America and Africa - Unlikely to swim between
continents - Wegener thought reptile covered
both continents during Pangaea period -
Fossils from fernlike plant Glossopteris -
Found in Africa, Australia, South America and
Antarctica -Wegener thought this showed
continents had to be connected at one point in
time Pangaea Climate Evidence of Continental
Drift - Fossils of warm weather plants were
found on island in Arctic Ocean - Wegener
thought island drifted from tropic regions -
Glacial deposits and grooved bedrock on South
America, Africa, India, and Australia - Shows
they were once covered with glaciers - No
glaciers exist in those areas today Wegener
thought they were all connected near the Earths
south pole at one time
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• Rock Evidence of Continental Drift
• If continents were connected as Pangaea,
  shouldnt rocks be similar on different
  continents? YES!
• Similar rock structures and types of rocks are
  found on different continents
• Appalachian Mountains (below left) in eastern
  United States are similar to mountains in
  Greenland and Western Europe (below right)
• South America and western Africa have similar
  rock structures

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- Wegener had some good evidence for Continental
Drift But the big questions of how, exactly
when or why this happened still werent
answered. - Most people rejected his idea of
Continental Drift - After Wegeners death, more
clues were found to support Continental
Drift. - New idea SeaFloor Spreading, helped
explain how the continents could move. -
Proposed by Harry Hess in 1960s - SeaFloor
Spreading as hot, less dense material is
forced up through the Earths crust in an
opening called a mid-ocean ridge, it turns and
flows sideways, carrying the seafloor away from
the ridge in both directions This would
cause continents to move away from each other
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• Evidence for SeaFloor Spreading
• Movement of sea floor
• Process of seafloor spreading
• Age evidence
• 1968 research ship Glomar Challenger
  gathered samples of sea floor rocks
• Checked age of rocks
• Rocks on sea floor near mid-ocean ridge were
  180 million years old or younger
• Rocks away from mid-ocean ridge near continents
  some were almost 4 billion years old
• WHY?

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Magnetic Clues - Magnetic field of Earth has a
North and South pole - Magnetic force leave at
the south pole and enter at the north pole -
During a magnetic reversal the magnetic forces
run in opposite way - Reversal has happened
many times in past - Iron bearing minerals
magnetite, which is in basalt, record Earths
magnetic field direction - Rocks show the
effects of the reversal new iron minerals are
formed - Magnetometer records magnetic data -
Magnetic alignment in the rocks reverses back and
forth over time these match and are parallel
with mid-ocean ridges Why is this Important? it
shows new rock was being formed at the mid-ocean
ridges
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• Plate Tectonics
• (pg. 280)
• Seafloor spreading let scientists know what was
  happening with the crust and upper mantle
• It also showed that there was more than just
  continents moving
• Larger sections were moving
• 1960 scientists developed a new theory that put
  continental drift together with seafloor
  spreading
• Theory of Plate Tectonics Earths crust and
  upper mantle are broken into sections theses
  sections called plates, move around on a layer
  of the mantle
• Which layer are the plates a part of?

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What causes Plate Tectonics? - Process of
heating and cooling, which causes movement of
particles is called convection current - Hot
particles rise, cool particles lower -
Continuous process keeps particles moving
creates energy - These convection currents
provide energy that moves plates Effects of
Plate Tectonics Plates are constantly
interacting with other plates What does this do
to the Earth? - Forms mountain ranges,
volcanoes, faults, rift valleys
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Three types of plate boundaries (pg. 281) 1)
Boundary between plates that are moving apart
divergent boundary 2) Boundary between plates
that are moving together convergent boundary.
- Area where one plate goes down into the
mantle is called the subduction zone. -
Volcanoes usually form near convergent boundaries
when the rock melts or mountains can form when
two plates collide and crumple up. 3) Boundary
where plates are sliding past each other
transform boundary