Topic 3: Soil Formation

Define the term weathering 

  Refers to the process by which rocks and minerals are broken down into smaller particles or altered in composition due to various natural forces. It is a key component in the rock cycle and contributes to soil formation.

Identify the agents of physical, chemical and biological weathering and describe how soil is formed through these three processes 


Physical Weathering:

Definition: Physical weathering, also known as mechanical weathering, involves the breakdown of rocks into smaller fragments without changing their chemical composition.

Agents:

Temperature changes: Expansion and contraction due to heating and cooling.

Freeze-thaw cycles: Water entering cracks in rocks and freezing, expanding, and causing the rock to break.

Abrasion: Physical grinding by particles carried by wind, water, or ice.

Root growth: Plant roots growing into rock crevices and causing fragmentation.


Chemical Weathering:

Definition: Chemical weathering involves the alteration of the rock's mineral composition through chemical reactions, often involving water and atmospheric gases.

Agents:

Hydrolysis: Reaction with water to form new minerals and soluble substances.

Oxidation: Reaction with oxygen, often affecting iron-rich minerals.

Carbonation: Reaction with carbon dioxide forming carbonic acid, which dissolves minerals.

Dissolution: Soluble minerals dissolve in water.


Biological Weathering:

Definition: Biological weathering occurs when living organisms contribute to the breakdown of rocks and minerals through physical or chemical means.

Agents:

Plant roots: Penetrating rock surfaces and producing acids that enhance weathering.

Microorganisms: Fungi and bacteria contributing to chemical weathering through acid production and other processes

Click this link for more understanding 

https://youtu.be/BxmAJMjJ5Nk?si=qo5R223OZU1Oof2g



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