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28 Cards in this Set
- Front
- Back
What is the hottest layer?
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inner core
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What is the coldest layer?
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crust
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What is the thickest layer?
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the mantle
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What is the smallest layer?
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crust
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What are the two metals that make up the core?
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iron and nickel
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Which rocks make up the continental crust?
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granite
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Which rocks make up the oceanic crust?
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basalt
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What is the lithosphere comprised of?
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crust and upper layer of mantle
rigid, brittle rock |
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How deep is the lithosphere?
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60 miles
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What is the asthenosphere?
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part of the mantle that flows and moves the plates of the Earth
(below lithosphere) |
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Name the layers of the Earth in order.
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1. crust
2. mantle 3. outer 4. inner |
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What are convection currents?
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- moves plates
- in the mantle |
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Who was Alfred Wegner?
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proposed continental drift hypothesis
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What is Pangaea?
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single ancient landmass where all continents are connected
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What is the ocean the surrounds Pangaea?
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Panthalassa
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What part of the Earth contains the plates?
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lithosphere
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What is the lithosphere comprised of?
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crust and upper mantle
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What evidence was used to complete the jigsaw puzzle?
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1. continents fit together like a jigsaw puzzle
2. similar fossils in eastern South America and western Africa from 870 mya 3. mountain ranges 4. South Africa and South America show evidence of ancient glaciers |
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Why was Wegner's theory not believed?
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he could not identify a force to explain continental drift
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What is a scientific theory?
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A theory summarizes a hypothesis that has been supported with repeated testing. It is valid as long as there is no evidence to dispute it.
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What is a law?
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accepted as truth
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What is the driving force of continental drift?
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convection currents in the mantle
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When was the evidence for the driving force for continental drift discovered?
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1947
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How was the evidence for the driving force for continental drift discovered?
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mapping the mid-Atlantic ridge
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What is the mid-atlantic ridge?
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underwater mountain chain around 80,000 km long in the Atlantic Ocean
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What did scientists discover at the Mid-Atlantic range?
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Scientists discovered rocks were not older than 170 myo. Some continental rocks are 4 byo.
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What occurs at the ridges?
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seafloor spreading
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What is seafloor spreading?
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at the ridges, new sea floor is being created as magma seeps up from below the surface
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