Physics of Skiing

Skiing is an old sport; the oldest artifacts date back over 4000 years. It was developed in the Scandinavian region, especially Norway, and didn't spread to the rest of Europe until the sixteenth or seventeenth century. It probably came over with Norwegian and German immigrants during the nineteenth century.

Skiing relies on many different forms physics. Newton's Laws of Motion, the transformation of potential energy into kinetic energy, air resistance, circular motion, even conservation of circular momentum is used as skiers pump upwards during a turn. Friction is by far the least understood of these forces. The surface of snow is a strange interaction between water, ice and water vapor, the three forms of water found on Earth. Snow changes properties and is difficult to measure and study in its natural environment.

Snow changes properties and is difficult to measure and study in its natural environment. Ice Crystals form when water vapor condenses around and freezes upon a foreign particle such as dust or sea salt. These Ice crystals then form various varieties of snow flakes.

Snowflakes can fall in many forms, including ferns, crystals and needles.

These snow flakes begin transforming as soon as they hit the ground. They begin to morph in a combination of melting, freezing, evaporation and sublimation*. They become needles, columns, and finally simple round pellets.

* Sublimation is when ice evaporates directly instead of melting first to water and then evaporating.

These pellets the bond again through a process of melting, freezing, evaporation and sublimation at their contact points, this creates a strong snow pack.

Snow Compaction and Work

One thing that slows a skier down is the compaction of the snow beneath a skier. Snow is mostly air and this allows a great degree of compaction. On packed trails, this compaction is negligible and contributes only slightly to the friction of the snow on the skis.

This diagram shows a skier who travels l distance on unpacked snow and sinks in h into the snow.

Logically, the distance the skier sinks in, h, is proportional to the skiers weight, FN. Work is defined as a force applied over a distance.

The work needed to propel the skier l distance through the snow is the same as the work done be the skiers weight along the height, h.

the force used to move the skier is defined as FFORWARD then

FN*h= FFORWARD*l

With different types of snow, a skier with the same weight will sink in different distances.