Weathering and Erosion
- Earth & Space
- Ages 8–11 · Grades 3–5
What you’ll find out
- Weathering breaks rock into smaller pieces through ice, roots, rain, wind and temperature change.
- Erosion carries the pieces away by water, wind and ice.
- Deposition drops the moving material in a new place.
No sign-up and no real names. In the lesson you check your understanding as you read, and practise until it sticks.
Breaking rock: weathering
Rock looks hard and strong, yet over time it breaks down into smaller and smaller pieces. This is called weathering. Water can seep into a crack in a rock, and if it freezes, it turns to ice and expands, pushing the crack wider. After many freezes the rock splits apart. Plant roots can also grow into cracks and slowly split rocks. Rain, wind and changes in temperature all help to wear rock down.
Moving rock: erosion
Once rock has been broken into pieces, those pieces are carried away. This is called erosion. Rivers carry sand, mud and pebbles downstream, while waves wear away cliffs along the coast. In deserts, the wind blows sand from place to place, and in cold regions huge sheets of ice drag rocks along. Over a very long time, a river can carve a deep valley. The pieces it carries are dropped somewhere new.
Curriculum links: NGSS 4-ESS2-1 · England KS2: Rocks · Cambridge Primary Stages 4–6: Earth and space · NCERT Environmental Studies, Classes 3–5