Which describes a characteristic of water that is responsible for frost wedging?
A Water condenses as it is heated
B Water contracts as it freezes
C Water expands as it freezes
D Water evaporates as it is heated
C Water expands as it freezes
C Water expands as it freezes is the characteristic of water that is responsible for frost wedging.
The correct answer is C) Water expands as it freezes.
To understand why this characteristic of water is responsible for frost wedging, let's break it down.
Frost wedging is a mechanical weathering process that occurs when water seeps into cracks in rocks, freezes, and expands. This expansion exerts pressure on the surrounding rock, causing it to crack and eventually break apart.
So, why does water's expansion when it freezes lead to frost wedging?
When most substances freeze, they contract and take up less space than when they were in a liquid state. However, water is unique because it behaves differently. As water molecules cool down and freeze, they form a hexagonal crystal structure. This process causes the molecules to arrange themselves in a way that takes up slightly more space than when they were in a liquid state. In other words, water expands when it freezes.
When water freezes in the cracks of rocks, the resulting ice takes up more space than the liquid water did. The expansion of the ice exerts tremendous pressure on the sides of the crack, leading to the widening and deepening of the crack over time. As this cycle repeats with each freeze-thaw cycle, the cracks become larger and eventually cause the rock to break apart, known as frost wedging.
In conclusion, it is the expansion of water when it freezes that contributes to the process of frost wedging.