Rivers (weathering and the river valley)

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  • Created by: revision
  • Created on: 09-03-17 17:07
What is mechanical weathering?
Mechanical weathering is the breakdown of rock without changing its chemical composition.
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Freeze-thaw weathering step ONE.
It happens when temperature alternates above and below 0 degrees celcius.
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Freeze-thaw weathering step TWO.
Water gets into rock that has cracks.
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Freeze-thaw weathering step THREE
When water freezes it expands, which puts pressure on the rock.
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Freeze-thaw weathering step FOUR.
When water thaws it contracts, which releases the pressure on the rock.
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Freeze-thaw weathering step FIVE.
Repeated freezing and thawing widens the cracks annd causes the rock to break up.
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What is chemical weathering?
Chemical weathering is the breakdown of rock by changing its chemical composition.
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Carbonation weathering step ONE.
Rainwater has carbon dioxide dissolved in it, which makes it a weak carbonic acid.
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Carbonation weathering step TWO.
Carbonic acids reacts with rock that contains calcium carbonate so the rocks are easily dissolved by rainwater.
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What is biological weathering?
Biological weathering is the breakdown of rocks by living things e.g. plant roots break down rocks by growing into cracks on their surfaces and pushing them apart.
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Other cards in this set

Card 2

Front

Freeze-thaw weathering step ONE.

Back

It happens when temperature alternates above and below 0 degrees celcius.

Card 3

Front

Freeze-thaw weathering step TWO.

Back

Preview of the front of card 3

Card 4

Front

Freeze-thaw weathering step THREE

Back

Preview of the front of card 4

Card 5

Front

Freeze-thaw weathering step FOUR.

Back

Preview of the front of card 5
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