Weathering
Geography: Edexcel IGCSE, topic 1.1.1
Weathering
Weathering is the breakdown of rocks in situ. It can be broken down into mechanical weathering, biological weathering and chemical weathering.
Mechanical (freeze-thaw)
- Mechanical (freeze-thaw) weathering is caused by drops in temperatures, especially during the evenings in the winter.
- Rocks break down because the water expands and contracts as the water freezes and melts, putting pressure on the rock.
Biological
- Biological weathering is when the roots of plants grow inside the rock, causing it to crack and break apart.
- It can also be when animals burrow inside the rock.
Chemical
- Chemical weathering happens because rainwater can be slightly acidic.
- The weakly acidic rainwater causes the breakdown of particular rocks over time.
Test yourself on Weathering
What kind of weathering happens when rocks are broken down by weakly acidic rainwater?