John Wheeler: There's more than one way to get rid of ice

FARGO — We are taught very early in school that water boils at 212 degrees, turning the liquid water into vapor. We are also taught the water cycle and how water evaporates. But if we think about it, when water is evaporating outside the air temperature is certainly not 212 degrees.

What really happens is that when water reaches a temperature of 212 degrees, it all boils away into vapor. But at cooler temperatures, some of the water, molecule-by-molecule, leaps off the water surface and becoming vapor. This is evaporation.



A glass with a half-inch of water will be dry in less than a week in your dry winter house. A similar thing happens to ice. Molecule-by-molecule, ice particles will leap off a patch of ice on a sidewalk and escape into the air as vapor.

This is called sublimation. During sunny, cold weather, it is possible to see ice patches on pavement slowly disappear through this process..