Question

Distinguish between physical and chemical weathering.

Answer 1

Physical Weathering :

1. Rock disintegration without any change in chemical constituents of rocks takes place.
2. Factors such as temperature, moisture, pressure cause the physical break-up of rocks.
3. It takes place in hot dry and cold areas due to rapid temperature changes.
4. Rocks are affected to great depths.
5. Its agents are temperature and moisture.

Chemical Weathering :

1. Minerals in rocks are dissolved or altered.
2. Temperature, moisture, etc., cause minerals in rocks to dissolve in water or convert them into other minerals.
3. It takes place in hot and humid areas due to the chemical action of minerals in rocks.
4. It mostly takes place near the surface of the earth.
5. Its agents are solution, oxidation, carbonation, and hydration.

Answer 2

• Physical weathering

1. It is the breakdown of rocks without changing their chemical composition, through the action of physical forces.
2. The constant freezing and thawing of rocks during the night and day leads to the expansion and contraction of rocks.
3. Exfoliation, block disintegration, granular disintegration etc., are the different types of weathering.

• Chemical weathering

1. Disintegration and decomposition of rocks due to chemical reactions is called chemical weathering.
2. This is predominantly high in the hot and humid regions such as the equatorial, tropical and sub tropical zones.
3. Chemical weathering takes place through the processes of oxidation, carbonation, solution and hydration.