ROANOKE TIMES
Copyright (c) 1997, Roanoke Times
DATE: Monday, January 20, 1997 TAG: 9701210119
SECTION: NEWSFUN PAGE: NF-1 EDITION: METRO
Our recent ice storm has made the roads around the Roanoke and New River valleys look as white as snow. And what's making the roads white may not even be snow or ice. It could be salt.
Yep, salt. People put salt on the roads and sidewalks to melt ice. But before we talk about melting ice, let's talk about how ice is made.
Water freezes at 32 degrees F. That's called water's freezing point. Ice makes the roads dangerous to drive on and sidewalks dangerous to walk on. That's where the salt comes in.
Salt dissolves in water. When you dissolve anything in water, the freezing point of the water gets lower. That means the temperature has to get even colder to freeze.
So, when people put salt on ice, the salt melts the first layer of ice into a salt and water mixture. The water doesn't refreeze because the salt lowered the freezing point to below the temperature outside. That lets the salt melt the rest of the ice until all that is left is salty water.
There can be problems with using salt, though. The salt can hurt plants that live near the road or sidewalk, and fish and frogs don't like saltwater that gets into streams and ponds. Salt also speeds up rust on cars and bridges.
- Ohio State University
LENGTH: Short : 32 linesby CNB