Weathering - SS3 Geography Lesson Note

Weathering refers to the physical, chemical, and biological processes that break down rocks and minerals into smaller particles over time. These processes are responsible for the decomposition of rocks at or near the Earth's surface. There are three main types of weathering:

 

a. Physical Weathering: Also known as mechanical weathering, this type involves the physical breakdown of rocks into smaller pieces without changing their chemical composition. Common physical weathering processes include frost wedging (expansion of water as it freezes cracks rocks), root wedging (roots growing in cracks), and abrasion from wind and water.

 

b. Chemical Weathering: In chemical weathering, rocks and minerals are broken down through chemical reactions. This can involve processes like dissolution (rock dissolving in water), hydrolysis (minerals reacting with water), and oxidation (reaction with oxygen). An example is the rusting of iron.

 

c. Biological Weathering: This type of weathering is caused by living organisms such as plants, lichens, and bacteria. These organisms can secrete acids that break down minerals or physically disrupt rocks as they grow.