Changes to Earth’s Surface

Science — Second Preparatory

Weathering: breaking rocks in place

Weathering→is the breaking down and decay of rocks in their place, without moving them. There are two types:

Comparison aspect	Main idea	Keywords
Mechanical weathering	rocks break into smaller pieces without their chemical composition changing. Causes include temperature changes which make the rock expand and contract water freezing in cracks and plant roots growing into cracks	rocksbreaksmallerpieces
Chemical weathering	the minerals in rocks decompose and their chemical composition changes. Causes include some minerals dissolving in water oxygen reacting with metals to form rust or oxides and carbon dioxide dissolved in rainwater reacting with limestone	mineralsrocksdecomposecomposition

Changes to Earth’s Surface · 3 / 7