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5 Cards in this Set
- Front
- Back
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What is sea floor spreading?
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When molten rock comes up from below a mid-ocean ridge. It cools and forms new ocean floor, pushing the older bits of ocean floor away to the side.
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What is the Earth's magnetic field?
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The Earth has two magnetic poles, magnetic north and south. Iron in magnets will point north
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How was drilling used to give evidence for sea floor spreading?
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Scientists drilled deep into the ocean floor on either side of the ridge. They found the farther away the rock, from the ridge, the older it is
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How was the shape of underwater rock used to give evidence of sea floor spreading?
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When molten rock cools quickly under water, it forms shaped like toothpaste blobs and pillows.
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Why does the rock of the ocean floor have a pattern of magnetic stripes?
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Because each time Earth's magentic field reverses, the iron in the sea floor changes its direction. The stripes give evidence of when these changes happened in history.
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