When Nature fails to drop enough snow or brings a January thaw, skiers use this to keep thing moving smoothly.
Once upon a time, making snow was a straightforward craft. One could simply grind up large blocks of ice and spread the pulverized material where desired or use a basic stand-in material such as cellulose powder or bits of paper. Nowadays, with the advent of better materials and machinery–and because the fluffy white stuff fascinates people to no end–there are myriad ways to pull off a big snow job for indoor or outdoor use using machine-made snow or artificial snow.
Machine-made snow has been substantially refined by the ski industry over the years. Snowmaking serves to extend the ski season or can rescue a dry winter, but it also has become important for controlling snow conditions as the number of skiers has increased and the mode of enjoying the slopes has evolved to include tubing, sledding, and snowboarding. Machine snow is also used in labs to learn how to forecast avalanches.
To make snow, water cooled to just above its freezing point is pumped under high pressure through the nozzles of a “snow gun.” Compressed air or electric fans are usually used to help atomize the water into fine droplets and to disperse them over a wide area where they hopefully will freeze before they hit the ground. If not, the snow will be too wet. Other ways to make snow include using a combination of water and compressed air that is frozen by liquid nitrogen, a method used primarily for indoor sports centers. Snow also can be made from carbon dioxide.
Visit “What’s That Stuff” to read more about artificial snow.
Excerpted with permission, Chemical & Engineering News
Copyright © 2004 American Chemical Society