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Most skiers assume that pressure or friction melts snow under the ski to make a slippery layer of water. But there just isn't enough pressure on skis to do that, according to University of California, Davis, chemist Timothy C. Donnelly. In fact, the problem of why ice is slippery at all was only solved in the 1990's, he said. Just how skis run over snow is a long-standing interest for Donnelly, a keen skier. He developed ski waxes that work in all types of snow conditions. On cold snow, hard ski waxes smooth the ski base and make it slick. On warmer, wet snow, softer waxes act more like lubricants to make the skis slide faster. Donnelly's waxes included a surfactant, or soap-like molecule. On cold snow, the surfactant stays inside: as conditions warm up, the surfactant is released and adapts the waxing to the conditions. Donnelly's research on ski waxes led to commercial products used by medal winners at the 1988 and 1994 Winter Games.

In 1996, °ÄÃÅÁùºÏ²Ê×ÊÁÏ¿â Berkeley chemist Gabor Somorjai discovered that oxygen atoms at the surface of ice crystals are vibrating much faster than those inside. This creates an outer layer that acts like a liquid, although the ice crystal is solid, and that's what makes ice slippery. Skis, snowboards and ice hockey pucks all swim on this semi-liquid layer. For ice skates, there's enough pressure to cause some melting as well, Donnelly said.

Donnelly is currently developing an environmentally friendly liquid deicer for uses as diverse as dog sled runners, fishing boats, light aircraft and microwave towers.