In search of speed

You couldn't have asked for a better day for a competition. It's minus five degrees, the sun's shining and there's not a breath of wind. The snow's perfect and the biathlete's in top form. He's one of the best he can win the race. Often there's only a few thousandths of a second between the victor and the vanquished, so the gliding ability of his skis is very important. And this depends on several factors, not least whether the wax mixture he's applied suits the particular type of snow.

Anyone looking for optimal ski performance must first understand the laws of friction. That is why wax and ski coating manufacturers are counting on the expertise of scientists at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg. The researchers have been studying the gliding ability of skis and know how to make ski athletes go like the wind. Prof. Dr. Matthias Scherge, Head of the new Microtrobilogy Center in Karlsruhe, says: The snow, the ski coating and the wax that is applied all unite to form a single entity. We can't alter the snow, but we can adapt both the wax and the coating to suit particular snow conditions. The scientists use a special technique to analyze the friction and gliding effects; they simulate the contact between a single snow crystal and the coating with the aid of a test rig, and then measure the coefficient of friction in relation to temperature. It's the first 10 to 15 nanometers of the coating surface that.........