How Does Ice Cause Mechanical Weathering?

Mechanical weathering due to ice occurs because water expands as it freezes. This expansion creates enough force to enlarge existing cracks and break pieces of rock from the larger formation to create sediment. Weathering due to ice exposes more surface area, allowing other forces of weathering to create more sediment.

Before large masses of rock move to the surface of the Earth, tectonic plate movement forms cracks. Once exposed, water enters these cracks. Freezing water expands with enough force to break metal pipes in a home and rocks in the environment. Scientists refer to this type of weathering as frost shattering. Each freeze and thaw cycle breaks more sediment from the parent rock.

Weathering is the physical and chemical breakdown of rocks near the surface of the Earth. Mechanical weathering involves physical breakdown of rock without altering its chemical composition. Wind, plant growth, water and ice cause physical weathering. Once sediment forms, erosion moves it to other locations. Weathering and erosion are not the same thing; however, weathering is sometimes seen as the first step of erosion. If a rock breaks and remains in the same location, the process is weathering. However, as soon as the rock rolls down a hill, it is undergoing erosion, according to the United States Geological Survey.