Three types of weathering
Earth's surface is always changing — usually so slowly we cannot see it. Weathering is when rock is broken down into smaller pieces where it is. There are three types.
Spot the weathering
Q1. Match each type of weathering to its description.
| Type | Description |
|---|---|
| Mechanical | |
| Chemical | |
| Biological |
Descriptions: a chemical reaction breaks the rock (like acid rain) • living things break the rock (like tree roots or mining) • the rock is physically broken without changing what it is (like freeze and thaw)
Q2. Classify each example as Mechanical, Chemical or Biological weathering.
| Example | M, C or B |
|---|---|
| Water freezes in a crack and splits the rock | |
| Tree roots crack a footpath | |
| Acid rain slowly eats away a limestone statue | |
| Rocks tumble in a river and get smaller and rounder | |
| People dig a mine into a hillside |
Q3. On your schoolground hunt, you found an example of weathering. Draw it and explain which type it is and why.
Q4. Weathering usually happens very slowly. About how long can it take to wear down a large rock or mountain? Why is this hard to notice?