The athletes competing for medals are not the only people who pass a stringent selection process at the Olympics.
There are also the Zamboni drivers.
Zamboni drivers simultaneously perform three operations: scraping away a thin film of ice, picking up the debris and laying down water to create a fine new layer of ice. One false move with the scraping blade and the ice is scarred with a gouge that could trip up players. Too much water leaves puddles that slow the puck, too little doesn't fill the ruts cut by the skates. The drivers also keep an eye on the temperature of the water, which is usually about 150 -- hot enough to remove the oxygen that slows freezing.
All this while driving about nine miles an hour, looking backward at the ice they leave behind, and keeping aware of a second Zamboni on the ice (in hockey matches, they usually drive in tandem). During each 15-minute intermission between periods, the drivers have about six minutes to cover the 200-by-100-foot sheet of ice, which leaves enough time for the new water to freeze before the players return. (A vast network of cooling tubes beneath the ice keeps the temperature at about 22 for hockey. The icemen must watch the temperature, too, taking regular readings as the arena heats up with cheering fans; too cold and the ice chips, too warm and the skates dig in.)
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