Biological, Physical and chemical weathering

Question 1

Define biological weathering

Answer 1

The action of plants and animals on the land

Question 2

What happens in biological weathering

Answer 2

1) Seeds fall into cracks in the rock and grow when moisture is present
2) The roots force their way into the cracks increasing the size of the cracks
3) Burrowing animal widen the cracks further
4) This results in the rocks breaking up

Question 3

What can physical weathering also be called

Answer 3

• Freeze-thaw or;

- frost action

Question 4

What happens in Physical weathering

Answer 4

1) Water gets into cracks in the rocks
2) When the temperature drops below freezing the water will expand as it turns to ice
3) This expansion puts pressure on rock around it, increasing the size of the cracks
4) Over time this causes the rock to weaken and so bits break off

Question 5

What happens in chemical weathering

Answer 5

1) Rainwater contains weak acids that can react with certain rock types
2) Carbonates in limestone are dissolved in these weak acids
3) This causes the rock to break and disintegrate