How does salt melt snow? © iStock

How does salt melt snow?

Gritting icy roads is a necessity when the UK has its annual snow-panic - but why is this the go-to method for clearing roads of snow?

Asked by: Anonymous

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Salt melts ice and snow by lowering its freezing point. Salt is best put on the roads before they freeze or before snow arrives. Then, as snow falls, the salt mixes with it, lowering its freezing point. The result is a brine solution, preventing subsequent ice forming. If roads are already frozen solid, salt is far less effective as there’s no liquid water on the surface.


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