Mechanical weathering

Science

Definition

Mechanical (physical) weathering is the breakdown of rocks into smaller pieces without changing their chemical composition. Common causes include frost wedging, root growth, thermal expansion, and abrasion by wind or water.

Examples

  • Water freezing in rock cracks and expanding, splitting the rock apart (frost wedging)
  • Tree roots growing into cracks and gradually prying rocks apart
  • Rocks tumbling in a river and becoming smooth and rounded

Related Terms

Chemical weathering Erosion and deposition Rock cycle Soil composition

Study This Concept

Practice mechanical weathering with free review games in these units:

Earth Science Unit 4: Weathering and Erosion