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
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.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
Authors
Subscription offer
Subscribe and save 50% on the shop price. Pay just £16.50 every 6 issues by Direct Debit. Receive every issue delivered direct to your door with FREE UK delivery.