Soil — Science STD 7 — Question

The soil is formed by the breaking down of rocks by the action of wind, water and climate. This process is called weathering, it broke down soil into small pieces that get mixed with humus and form soil. There are two different types of weathering. Physical weathering and chemical weathering. Mechanical (physical) weathering is the breakdown of rock into smaller particles due to such factors as freezing and thawing, release of pressure, water absorption, salt crystal formation, land mass uplift, expansion and contraction from the sun or fire, plant root growth, actions of animals, abrasion, or other means that do not directly affect the rock's chemistry. Chemical weathering is the dissolution, carbonation, oxidation, or hydrolysis of rock and mineral by chemical means only, mostly from reactions with water or the acids contained in rainwater. Other materials are formed in the process. Warm, tropical climates are ideal environments for chemical weathering to take place as the chemical reactions are quickened by the bountiful rain and warm temperatures.