SCIENCE LAB SCHEME : DIRTY ICE

Clear Advantage : On dirty ice, fewer somersaults : What's the worst part of winter? The perpetual shoveling of snow? The bitter wind that whips across your face?

Some might say the real villain is ice, which causes slips and falls, sends cars spinning and delays flights. Engineers in Chicago have made it their mission to better understand the basics of ice and, better yet, how to get rid of it.

Their latest research published in the journal Materials Horizons, reveals that while water freezes, even tiny amounts of containment significantly decreases the tendency to stick to a surface.

The discovery could someday lead to the less damaging de-icing salts - which corrode metal and infrastructure and harm the environment or lead to alternative melting agents.

Researchers have been studying how ice adheres to surfaces for a long time, though their research almost always focuses on pure ice, said Sushant Anand, a mechanical engineer at the University of Illinois Chicago who led the study.

'' But water isn't pure on the roads or in the ocean,'' he said. '' And when this water freezes on surfaces, then it forms thin ice that has all these contaminants inside.''

To study how ''dirty'' ice sticks to surfaces, Dr. Anand's team mixed pure water with concentrations of table salt, soap or alcohol. They then put droplets of the contaminated water on surfaces made of copper, glass or silicon, and measured how much force it took to unstick them after they froze.

All of the contaminants weakened the ice's grip.

But the best performers were salt [not surprisingly, since it is already widely used to de-ice roads] and alcohol. [Katrina Miller].