Weathering is the wear and tear of any material under an external influence. Natural weathering or erosion of a certain kind can be chemical and mechanical. The causal elements or causes can be water, ice, gas, temperature, pressure or even plants. Natural weathering is not the same as manual or artificial weathering. Wear and tear of materials or objects as well as nature due to human intervention cannot be classified into the same definition.
What is Chemical Weathering?
Any kind of weathering will have an impact on the form, structure, texture, composition and even properties of the object in question. It could be a rock, the top soil, a terrain or a natural structure. Chemical weathering involves the change in the composition of the object. Imagine rocks dissolving in water or decomposing due to exposure to certain liquids or gases. Rocks may also react to certain minerals or metals found abundantly. Water, ice, steam, temperature and pressure may cause a chemical reaction in natural objects and that can lead to the change in the chemical composition. This is known as chemical weathering. Chemical weathering can be facilitated by oxidation, especially in objects with iron as the main component. Hydrolysis can facilitate chemical weathering. There are many such chemical processes or reactions that cause chemical weathering.
What is Mechanical Weathering?
Mechanical weathering is simpler. It involves the breaking down of an object into smaller pieces and this is mostly done by sheer force. Abrasion, exfoliation, freeze and thaw cycles or just impact of a natural force onto an object causing a simple rupture, crack or disintegration of the object into smaller pieces; all these processes lead to mechanical weathering. Friction, which could be due to water, air, natural objects including plants and two objects of similar or dissimilar nature coming in constant contact with each other, can cause mechanical weather. Strong winds and river flows, waves, the freeze and thaw cycle in colder regions, groundwater force and movement, trapped pressure or heat in the crust and even tectonic movements can cause mechanical weathering.
Difference Between Chemical and Mechanical Weathering
Both are natural weathering methods. They pertain to naturally occurring materials by natural factors. Manmade objects and human intervention do not come into play. Chemical weathering causes a change in the composition, texture, form and properties of an object. Mechanical weathering simply affects the structure or the physical form, size, weight and the texture in rare cases. It doesn’t impact the composition of minerals or metals, compounds or any such formation/property of the object.
