Physical Weathering Examples

Physical weathering is a naturally or artificially occurring geological phenomenon in which rocks change their physical properties without affecting their chemical composition. Basically, the rocks are still made up of the same types of rocks and contain the same minerals they once did, they are just no longer in the same size or shape as before.

Natural physical weathering can result from either a sudden geological incident like a landslide, earthquake, avalanche, or volcanic eruption. It can also be a slow process like erosion or soil breakdown.

1. Rivers

Rivers and moving bodies of water like waves in a lake are responsible for a lot of the physical weathering that takes place. As rocks are lifted by the moving water, they either crash back down to the river bed or sea floor and slowly break, or they collide with other rocks or objects like fallen logs, causing damage to the surface. Over time, these rocks will lose their surfaces and become more rounded and smooth.

2. Ice

Water can also affect the physical weathering of rocks through much faster means, such as when water gets into the cracks and crevices of rock and freezes, causing the rock to break and occasionally even shatter in something much like an explosion. This phenomenon also happens in streets and roads, causing much the same result as ice wedges form and break up the road's rock composite. Glaciers are also responsible for a good deal of physical weathering as the move along the rocky surface, and as they freeze and melt and refreeze on top of rocky soil.

3. Plant Growth

Plants are responsible for the physical weathering of rocks as their roots grow up through the surface of the ground and rock face. These roots eventually push up on the rock with enough force that the rock weakens, causing cracks and crevices to form that can eventually led to breakage.

4. Physical Weathering through Chemicals

Certain chemicals can weather rocks. Salt water that gets into the crevices in rocks then evaporates, leaving the salt crystals behind. Those salt crystals expand as they're heated, causing pressure that forces the rock to break. Sodium sulfate, magnesium sulfate, and calcium chloride are other chemicals that can weather rocks through contact, especially with the interior of the rock structure.