Book 5, Question 63
Rock Breakers! Why Does Weather Break Rock?
Rain gets into tiny cracks in rock. When that water freezes, it turns into ice and takes up more space, which pushes the crack wider. After many freezes and thaws, pieces of rock can break off.
From the book
Page from A Million Whys Book 5
More fun facts
- Weathering is the breaking down of rock by things like heating and cooling, ice, plants and acids.
- Water seeps into cracks, freezes and expands, so the ice works like a wedge.
- This freeze and thaw cycle is called frost wedging.
- Plant roots growing into cracks can push rock apart.
- Heating and cooling make minerals in rock swell and shrink until they break apart.
- Water mixed with weak acid can slowly dissolve rock and carry it away.
- After ice splits rock, melting water carries the tiny pieces away. That is erosion.
Sources: National Geographic Education, National Park Service, National Park Service
Questions kids ask
What is the difference between weathering and erosion?
Weathering breaks rock into pieces. Erosion carries those pieces somewhere else.