Physical vs Chemical weathering

Carbon Dioxide

-CO2 dissolves in rain water and creates carbonic acid -Carbonic acid easily weathers limestone and marble

Acid Rain

-Compounds (nitrogen and sulfur oxides) from burning coal, oil and gas react chemically with water forming acids. -Most unpolluted rain has a slightly acidic pH, while acid rain can have a pH as low as 4 (Source) -Acid rain causes very rapid chemical weathering

oxygen related chemical weathering

-Iron combines with oxygen in the presence of water in a processes called oxidation -The product of oxidation is rust

Other types of physical weathering

-Rushing water wearing away stones such as in a stream -Wind carrying bits of sand

physical weathering

-Temperature change is the major force in this type of weathering

How temperature is a form of physical weathering

-Water fills the cracks of rocks naturally during rainstorms but if the temperature falls and causes the water to freeze it expands in the cracks and may push hard enough to split the rock -In a similar way, plants, especially trees, may grow in the cracks of rocks sending there roots down deep into the cracks looking for water. As the roots grow the pressure can cause the rock to split.

Chemical Weathering

-is the process in which the chemical composition of rocks is changed from the exposure to the environment. -Chemical Weathering is caused by action of water. This type of weathering affects the minerals within the rocks. Rain, streams, and ocean water dissolves minerals from rocks, causing the rocks to crumble.

What causes weathering?

water, ice, chemicals, plants and changing temperature

weathering

The breaking down of rocks into smaller pieces.