Winter weather can mean treacherous driving across much of the country. Road crews spread rock salt all over the highways and byways.

Though environmentalists and the academics who give them cultural ammunition don't like salt on roads, it works a whole lot better than the expensive vegetable juice alternatives that get promoted. But why?

The answer is a fascinating look into the world of chemistry and this week the group at ACS Reactions breaks down how ice keeps the roads safe when bad weather hits.

Winter weather can mean treacherous driving across much of the country. Road crews spread rock salt all over the highways and byways, but why? Credit: The American Chemical Society