What is physical weathering ?
Physical weathering, also known as mechanical weathering, refers to the process of breaking down rocks and other geological materials into smaller pieces without altering their chemical composition. This type of weathering is typically caused by physical factors such as temperature changes, freeze-thaw cycles, abrasion, and the growth of plant roots.
Temperature changes: When rocks are repeatedly exposed to changes in temperature, such as through heating and cooling cycles, they can expand and contract. This expansion and contraction can cause the rocks to crack and eventually break apart.
Freeze-thaw cycles: In regions with freezing temperatures, water can seep into cracks within rocks. When the water freezes, it expands and exerts pressure on the surrounding rock, leading to the formation of cracks. With subsequent thawing of the ice, the cracks can widen, causing the rock to disintegrate over time.
Abrasion: Rocks can undergo physical weathering due to abrasion, which occurs when they are subjected to rubbing or scraping against other materials. Examples of abrasion include the grinding action of windblown sand, the scraping effect of moving glaciers, or the pounding of waves against coastal rocks.
Plant roots: The growth of plant roots can contribute to physical weathering. As roots grow, they can exert pressure on rocks, causing them to crack and break apart.
Overall, physical weathering is a vital process that gradually breaks down rocks into smaller fragments, thereby aiding in the formation of soils and shaping the landscape.