what is meant by physical and chemical weathering??
Answers
Explanation:
Weathering is a process that breaks down exposed stone and rock, causing it to split apart or wear away. ... Different forces can cause rocks to become weathered: Physical weathering is caused by purely mechanical changes to the rock, while chemical weathering is caused by chemical reactions.
Answer:
Weathering is a process that breaks down exposed stone and rock, causing it to split apart or wear away. ... Different forces can cause rocks to become weathered: Physical weathering is caused by purely mechanical changes to the rock, while chemical weathering is caused by chemical reactions.
Physical weathering, sometimes called mechanical weathering, refers to processes that break down the structure of rock without changing its components. One common way this occurs is wedging. Water flows into holes and cracks in the rock, then freezes. When water freezes, it expands, causing the holes to grow larger. Salt wedging occurs when seawater in these cracks evaporates, leaving salt deposits behind that press outward on the rock. Plants may also cause wedging; plant roots can also grow into these holes and cracks and exert pressure on rock. Over time, the pressure exerting by wedging will expand gaps and cracks in the rock until large sections of the rock split apart completely.
Chemical weathering does not cause physical damage to rock but rather is a reaction between the chemical composition of the rock and outside chemicals. Chemical weathering can make a rock more vulnerable to physical weathering forces. For instance, oxidation is a process by which oxygen in the air reacts to chemicals in the rock. Iron in rocks can react with oxygen to form iron oxide, or rust. Rust is weaker than iron and makes the rock more likely to degrade. Hydration is a reaction in which molecules of water are incorporated into the structure of a rock. For instance, hydration causes the mineral anhydrate to convert into gypsum, a less dense mineral that is more vulnerable to outside physical weathering forces.