Winter has finally arrived in Prince George, with a vengeance if the amount of snow falling is any measure. It has arrived just in time for the Winter Olympics which are happening half-a-world away.
It always amazes me just how much science has influenced sports over the past 40 years. Each athlete is now supported by a whole team of scientists and technicians finetuning their performance.
Everything from nutritionally stringent diets to the latest advances in material science to the inclusion of a sports psychologist as part of an athlete's core team finds a place in elite athletics.
At a more fundamental level, sports rely heavily on scientific principles. Take alpine skiing as an example. In principle, it's a relatively simple sport - you just stand on a couple of boards and slide down a slope at ridiculously high speeds!
But science is involved in everything from the modern lightweight, durable carbon-fibre materials used to make skis, poles, and boots to the engineering of the bindings which allows them to release when necessary and only when necessary. With the punishment delivered during a two-minute descent in an Olympic downhill, releasing only when necessary is a major concern.
Modern video equipment and slow-motion capture technology used in televising the games provide shots of skiers carving corners and graphic evidence of the punishment both their equipment and body go through in completing a downhill run. Indeed, in any form of skiing, the forces involved are amazing.
At an even more fundamental level though, the most important science for a downhill skier is the physics - the physics of falling and the physics of friction. When I say falling, I don't mean falling over on the slopes - although it happens and can be quite painful as some of our athletes will attest.
No. From a physics point of view, downhill skiing down involves the force of gravity, which pulls or "accelerates" the skier down the slope, and the force of friction which counteracts gravity and slows the skier down.
The impetus for getting from the top of a hill to the bottom is nothing more than gravity. Mass and gravity equal acceleration.
Downhill skiing is a process that can be best described as a controlled fall. This, of course, is why good skiers ski the "fall line", which is the direct line that any falling object will take down the hill. It is the line taken by Manuel-Osborne Paradis to achieve the best time.
Of course, it is a little more complicated than simply falling.
For example, the acceleration due to gravity should result in a skier's velocity perpetually increasing. But even speed skiers - the ones with the crazy helmets, the spandex suits, and the oversized skis - can only reach speeds of 200 kilometres per hour. This is their "terminal" velocity, which is the fastest speed it is possible for them to go.
The reason for this terminal velocity is, in part, friction in the form of "air resistance" - maybe "air friction" would be a better term. Any object travelling through the air must move the molecules of air out of the way and this requires energy. The energy required to cut through the air takes away energy from the forces pulling the skier down the slope.
In addition, the molecules of air also clutch and grab at the skier, resulting in drag. Reducing the drag is why skintight clothing is all the rage. Loose clothing slows a skier down.
It is the sum of air resistance and friction between the skis and the snow that results in a terminal velocity for skiers.
Friction is also important in other aspects of skiing. Friction between the skis and the slope allow a skier to turn, to hold an edge, to handle moguls, or even flat groomed runs. If the skis don't grab the snow, or the snow the skis, then a wipeout occurs.
For the cross country skiers, friction is critical. The right type of wax can allow a cross country skier to actually climb a snow-covered slope.
Wax is simply a long chain hydrocarbon with the atoms and molecules interacting with the ice crystals in the snow. These molecular interactions allow the skis to grip the snow rather than just sliding past. And the right type of interaction is critical for cross country skiing which is why there are so many different types of wax and why so much care is employed in getting ready for an Olympic race. But even for cross country skiers, going down a slope is still a matter of falling down an inclined plane.
Falling and friction - these are the forces behind skiing. Understanding physics can result in a gold medal performance. Let's hope our Canadian athletes can bring home a few medals from these games.
