Mechanical weathering occurs due to situations such as wind, rain, ice or lava that carry away materials. Mechanical weathering is a set of geological phenomena that causes rocks, soil and minerals to break down without the formation of new substances.
Wind-based mechanical weathering is called aeolian weathering. The constant blowing of wind carrying fine, erosive particles can chip away geographical features such as cliffs. Regions that are constantly subject to this form of weathering are called deflation zones. Deserts are a prime example of deflation zones.
Rain-based weathering results when the constant force that raindrops exert on certain rocks causes them to break down. This should not be confused with the chemical erosion that occurs when rainwater reacts with certain minerals, causing them to dissolve.
Ice-based weathering occurs when large sheets of ice, such as glaciers, slide over surfaces, causing them to erode. The glaciers carry along the material that is underneath them until they reach the sea. This effect can be seen in the smooth treads that glaciers leave as they move, called ogives.
Lava can cause mechanical weathering when it sweeps away rock and rubble without reacting with it. Lava is more likely to cause chemical weathering, as its high temperature accelerates reaction with materials that it meets while flowing.