Grade 9 Geography Term 3 Test Scope Vocabulary

Vocabulary flashcards covering key terms and concepts from the Grade 9 Social Science Term 3 Geography test scope on weathering, erosion, deposition, and agricultural soil erosion.

Physical weathering

The mechanical breakdown of rocks into smaller fragments without altering their chemical composition.

Freeze and Thaw method

A physical weathering process where water enters cracks in rock, freezes and expands, widening the cracks until the rock splits.

Expansion and contraction

A physical weathering process where daily heating and cooling cause rocks to repeatedly expand and contract, leading to cracking and stress.

Granular disintegration

A physical weathering process in which rocks made of different minerals break down into individual mineral grains due to unequal expansion and contraction.

Chemical weathering

The process by which rocks are broken down through chemical reactions that alter their original mineral composition.

Oxidation

A chemical weathering process that occurs when oxygen reacts with minerals in rocks, such as iron, causing rusting and weakening of the rock structure.

Hydrolysis

A chemical weathering process where minerals in rock react chemically with water, altering their composition and breaking down the rock.

Acid rain

Rainfall made acidic by pollutants, which reacts chemically with minerals in rocks, causing rapid chemical weathering.

Biological weathering

The breakdown of rocks caused by the activities and presence of living organisms.

Weathering caused by animals

Biological weathering that occurs when animals burrow, dig, or walk on rocks, breaking them apart and exposing underlying rock surfaces.

Weathering caused by plants

Biological weathering that occurs when plant roots grow into rock cracks and exert pressure, wedging the rock apart.

Erosion

The process of wearing away and transporting weathered rock, soil, and sediment from one location to another by wind, water, or ice.

Deposition

The laying down or dropping of eroded rock, soil, and sediment in new locations when transporting agents such as water or wind lose energy.

Agriculture contribution to soil erosion

The acceleration of topsoil loss caused by human farming activities, such as land clearing, overgrazing, and improper tilling, which expose bare soil to wind and water.