Section 1 - Rivers (Weathering)

Question 1

Name the 3 types of weathering

Answer 1

• mechanical
• chemical
• biological

Question 2

What is mechanical weathering?

Answer 2

The breakdown of rock without changing its chemical compostion

Question 3

Name a type of mechanical weathering and its process

Answer 3

Freeze-thaw weathering

1. When temp of water alternates above and below 0 degrees
2. Water gets into the cracks in rocks (granite)
3. When the water freezes it expands, putting pressure on the rock
4. When the water thaws it contracts, releasing the pressure on the rock
5. Repeated freezing and thawing widens the crack and causes the rock to break up

Question 4

What is chemical weathering?

Answer 4

The breakdown of rocks by changing their chemical composition

Question 5

Name a type of chemical weathering and its process

Answer 5

Carbonation weathering

1. Rainwater has CO2 dissolved in it, which makes it a weak carbonic acid
2. Carbonic acids react with rocks that contain calcium carbonate (limestone) so the rocks are dissolved by the rain water

Question 6

What is biological weathering?

Answer 6

The breakdown of rocks by living things

Question 7

Name a type of biological weathering and its process

Answer 7

Plant roots break down rocks by growing into the cracks on the rocks surface and push them apart

Question 8

What is weathering in drainage basins?

Answer 8

The breakdown of rocks WHERE THEY ARE (the material doesn’t get transported like in erosion)