Being the Econ major I am I was paging through the economist today and was suprised to come upon this, thought it was interesting:
Skiing
Not waxing lyrical
Dec 14th 2005
From The Economist print edition
Using ski wax can trap dirt, and thus slow down the skier
<!--back--> THIS season, like every previous one, recreational and racing skiers alike will apply wax to their skis in the hope of schussing that little bit faster. They will do so after assessing the air's temperature, its humidity and the prevailing snow conditions, so as to determine exactly which wax they should use. Not any old wax will do. Some are formulated for use over cold, dry snow and others for warmer, wetter stuff. Aficionados who want to extract the maximum advantage will take great care over which they choose.
But recent research suggests they are wasting their time, not merely in their choice of wax, but in bothering to wax their skis at all. A study by Leonid Kuzmin, a former cross-country racing champion turned ski coach who is now a doctoral student at Mid-Sweden University, concludes that for runs of more than a couple of hundred metres, the presence of ski wax slows the skier down. Admittedly, Mr Kuzmin's research was conducted on cross-country skiers, but he believes it will prove true for downhill racers as well.
<cf_floatingcontent></cf_floatingcontent> The way in which a ski slides over the snow boils down to the way in which friction between the base of the ski and the surface of the snow melts that snow, transforming it into a thin layer of water. The ski then floats across this layer. Indeed, snowboarding, ice skating and sledging also rely on this principle.
The depth of the water layer is crucial. If it is too thin, which can happen at very low temperatures, the ski sticks. Skiers typically try to overcome this friction by applying hard wax. If it is too thick, which can happen at warmer temperatures, it can create suction that makes it harder to slide over the water layer. To avoid that, skiers typically apply soft wax.
The base layer of modern skis is made from a substance called ultra-high-molecular-weight polyethylene. This fantastic plastic has molecules far longer than those of regular polyethylene, and these molecules are, in addition, packed tightly into a crystal structure rather than being scattered at random. The result is a tough material that has a low coefficient of friction—comparable to that of Teflon—and is highly resistant to abrasion. Its properties are so useful and unusual that it is used not only to create the base layer of skis, but also to make bulletproof jackets and artificial hip and knee joints.
In fact, Mr Kuzmin suspected that this wonder material was so good that waxing it was no longer necessary. He therefore decided to conduct a series of experiments with waxed and unwaxed skis. He commissioned a few pairs of transparent skis that a volunteer then took out on to a test slope. That done, he examined the skis and found that those treated with wax attracted more dirt than the ones that were unwaxed.
Moreover, Mr Kuzmin also recorded the speeds the volunteer reached while gliding down the test slope. He found that after distances of just a couple of hundred metres, gliding on unwaxed skis was faster than on their waxed counterparts.
Skiers can thus, it seems, forget about long hours spent ironing wax on to their skis and devote more of their time to the slopes. Before ski-wax makers pack up shop, however, business opportunities do still exist. Mr Kuzmin's research pertains only to glide wax—that is, wax intended to make skis glide faster. Cross-country skiing also employs a second form, kick wax, which has the opposite effect.
Kick wax is applied to the parts of the blades of cross-country skis that are directly under the skier's feet. These do not (or, at least, should not) touch the ground when the skier is gliding. On flat terrain, such wax allows the skier to push off and on uphill climbs it prevents him from slipping backwards. Manufacturers will be pleased to hear that kick wax remains essential to cross-country skiing.
