click below
click below
Normal Size Small Size show me how
Science Test Weather
First test after break
Question | Answer |
---|---|
Weathering | The physical and/or chemical breakdown of rock into smaller particles called sediment |
Why do rocks weather? | They weather because they are adjusting to a new enviorment diffrent from the one they formed in |
When does weathering take place? | When rocks are exposed to water, air, falls due to gravity, and living things |
Where does weathering occur? | It occurs near the earths surface |
What is physical weathering known as? | Mechanical weathering |
Physical weathering | The breakdown of rocks into smaller pieces without a change in chemical composition |
What are the 6 most common types of physical weathering? | frost action, abrasion, plant action, exfoliation, expansion and contraction, gravity |
Abrasion | The grinding away of rocks by friction with other rocks. ex: sea glass |
Plant Action | A plant grows in a rock and the pressure makes cracks allowing it to grow |
Exfoliation | The peeling away of outer layers of rocks formed when a release of pressure causes the rock to crack parallel to the surface |
Expansion and contraction | caused by heating and cooling can cause to break rocks |
Gravity | As rocks weather, the broken pieces are pulled downhill |
Chemical weathering | the breakdown of rocks by chemical action that results in a change in the mineral composition of the rock |
What are the main agents that cause chemical weathering? | Oxidation, hydration, orgaicacid decay, carbonation |
Oxidation | Occurs when oxygen unites chemically with minerals |
Hydration | Occurs when water chemically combines with minerals |
organic acid decay | acid produced from decaying plants or animals dissolve in water and break down rock |
carbonation | carbon dioxide chemically combines with minerals |
What does weathering rate depend on? | Surface area and particle size, climate, mineral composition |
Surface area and particle size | The smaller the particle, the greater the weathering rate |
Climate | weather always occurs ore in humid climates. Cld regions have physical weathering while hot regions have chemical weathering. |
Mineral composition | Rocks that are harder are more resistant to weathering |
Chemical weathering | the breakdown of rocks by chemical action that results in a change in the mineral composition of the rock |
What are the main agents that cause chemical weathering? | Oxidation, hydration, orgaicacid decay, carbonation |
Oxidation | Occurs when oxygen unites chemically with minerals |
Hydration | Occurs when water chemically combines with minerals |
organic acid decay | acid produced from decaying plants or animals dissolve in water and break down rock |
carbonation | carbon dioxide chemically combines with minerals |
What does weathering rate depend on? | Surface area and particle size, climate, mineral composition |
Surface area and particle size | The smaller the particle, the greater the weathering rate |
Climate | weather always occurs ore in humid climates. Cld regions have physical weathering while hot regions have chemical weathering. |
Mineral composition | Rocks that are harder are more resistant to weathering (they weather harder) |