Physical Weathering
Science: KS3, topic 2.5.7
Physical Weathering
Weathering is when rocks break down into smaller pieces. There are three types of weathering; physical, chemical and biological.
Physical weathering
- Physical weathering is mechanical weathering.
- There is no chemical change in the rocks.
- It is caused by the wind, rain and temperature.
- There are two main types of weathering: freeze-thaw and onion skin weathering.
Freeze-thaw weathering
- When it rains, water fills cracks in rocks.
- If this water freezes, it expands.
- This expansion increases the size of the crack or breaks apart the rock.
Onion-skin weathering
- This type of weathering is also called exfoliation.
- Onion-skin weathering commonly happens in deserts.
- The sun heats up the rock, which causes it to expand.
- When it cools, it contracts and gets smaller.
- If this process is repeated many times, cracks will form and bits of rock will fall off.
Test yourself on Physical Weathering
Freeze-Thaw Weathering
Onion Skin Weathering
Which type of weathering is most common in deserts?