Ski
skiing. For the place in Norway, see Ski, Norway.
A ski is a long flat device designed to help the user slide over snow. A ski is pointed and curved upwards at the front to prevent it digging into the snow and the user is attached by a bindings to the skier's ski boots. Also, a ski may denote a similar device used for other purposes than skiing, e.g., for steering snowmobiles.
Construction
Skis were originally wooden planks made from a single piece of wood. They are now usually made from a complex assembly of components including glass fiber Kevlar or related composite materials, though many may still contain a wooden core.
Most varieties of skis have a metal edge running the length of the sides that once sharpened allow the ski to grip more effectively on hard packed snow and ice.
Shape
The sides of all skis describe a parabola, making the ski narrower under the skiers foot than at the tip and tail. By setting the ski at an angle so that the edge cuts into the snow, the ski will follow the parabloa and hence turn the skier, a practice known as carving a turn. Faced by competition from snowboarding, during the 1990s this shaping of the ski became significantly more pronounced to make it both easier for skiers to carve turns, and to dramatically increase the turning sensation experienced. Such skis were once termed carving skis, or shaped skis or parabolic skis to differentiate them from the more traditional straighter skis, but nearly all modern skis have this more pronounced shape now. For other turning techniques, see Skiing.
Types
Many types of skis exist, all designed for use different situations, of which the following are a selection.
Downhill ski
Downhill skis are shaped to promote easy turning. The ski binding anchors the foot firmly to the ski at heel and toe. It is spring-loaded, detaching the ski from the foot in case excessive force is applied. The ski is turned by applying a mixture of pressure, rotation and angle.
Alpine ski touring ski
Alpine ski touring ski. This type of ski is ususally a light-weight downhill ski with an alpine touring binding.
Telemark ski
Telemark ski. A downhill or touring ski, where the binding attaches only at the toe. The Telemark ski was the first ski with an inwards-turned waist which made it much easier for skiers to turn. It was pioneered by Sondre Norheim of Telemark, Norway. The fact that the foot is only attached to the ski at the toes, means that specialised more flexible ski boots are used, and a specific turning technique involving pushing one foot forward and lifting the heel of the other foot is used.
Cross-country ski
Cross-country skis are very light and narrow, and usually have quite straight edges. The bindings attach at the toes only. They are usually coated with wax to reduce friction during forward motion, but also to get adhesion when going uphill. Some models may have patterns on the bottom to increase the friction when the ski slides backward. These skis are also used in biathlons.
Backcountry ski
Skis for mountain/backcountry/cross-country free range skiing which are designed for skiing on unbroken snow, where an established track is lacking. These are characteristically quite wide, and with cable bindings to provide general sturdyness, and to better extract ones feet from deep snowbanks, in case it should be impossible to reach the bindings by hand. This is also the model used by military forces trained to fight in winter conditions, and the most closely related to the historical ski.
Ski jumping ski
Skis for ski jumping. Long and wide skis, with bindings attaching at the toe.
See also
