Mechanical weathering is a type of weathering that causes rocks to break down into smaller pieces without changing their composition. This process is also known as physical weathering. Mechanical weathering occurs due to various reasons such as wind, ice, weather, water, acids, and chemical reactions. Some of the key processes involved in mechanical weathering are:

• Freeze-thaw weathering or Frost Wedging: This process occurs when water seeps into cracks and crevices in rock. If temperatures drop low enough, the water will freeze and expand, causing the rock to split. When ice melts, liquid water carries away the tiny rock fragments lost in the split.

• Exfoliation weathering or Unloading: This process occurs when rocks that were once buried deep beneath the Earths surface are exposed due to erosion. As the pressure on the rock decreases, the outer layers of the rock expand and crack, causing the rock to break apart.

• Thermal Expansion: Changes in temperature cause rock to expand (with heat) and contract (with cold), which can cause the rock to break into fragments.

• Abrasion and Impact: In abrasion, one rock bumps against another rock, causing pieces to break off. Gravity causes abrasion as a rock tumbles down a mountainside or cliff. Impact occurs when rocks collide with each other, causing pieces to break off.

• Salt weathering or Haloclasty: This process occurs when salt crystals grow in the pores and cracks of rocks. As the salt crystals grow, they exert pressure on the rock, causing it to break apart.

Mechanical weathering is an important process that contributes to the formation of many geological features such as canyons, valleys, and rock formations.