Download B3a Worksheet 3: DNA

Worksheet C2a 1
The structure of the Earth
Through the Earth
1. Name each of the layers labelled (i) to (iii):
(i)
(ii)
(iii)
(i)
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(ii)
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(iii)
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2. Name the metal in the Earth’s core: ________________________________________
3. What is the lithosphere?
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Plate tectonics
4. Magma is molten rock. It escapes to the surface of the Earth through weak
spots in the crust. Explain why magma can reach the surface in this way.
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5. What is a tectonic plate?
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Worksheet C2a 1 continued
6. About how fast do tectonic plates move?
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7. Are tectonic plates more dense than the mantle or less dense? Explain how
you know:
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Extension
8. (i) Explain why it is difficult to study the structure of the Earth directly – and
why instead scientists have to study the seismic waves produced by
earthquakes or man-made explosions:
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(ii) Explain why tectonic plates move:
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9. When two plates meet, an oceanic plate may be subducted (pushed under) a
continental plate.
(i) Explain why this happens:
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(ii) What happens to the subducted oceanic plate?
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