The increased national interest in figure skating has generated plenty of attention for the sport, but one of its key ingredients remains an afterthought.

	T O P   N E W S

The ice.

Spectators take it for granted at shows and competitions. It's just the shiny, smooth and inviting surface on which great athletes display remarkable skill. But it's hardly a passive player. Problems in an ice surface can ruin even the finest performance, while optimal ice conditions can enhance a skater's ability to thrill the crowd.

Baseball and football fans have long recognized that a game played on artificial turf can be very different from one played on natural grass. But many skating fans do not understand why figure skaters don't like to practice at rinks that cater to the needs of hockey players or why hockey players might whine about the sort of ice that figure skaters consider ideal.

A BRIEF HISTORY LESSON helps shed light on the matter. Indeed, the origins of skating and the conditions under which it exists today are dramatically different.

Ice skating originated as a form of winter transportation on the frozen lakes, rivers, and canals of northern Europe. But when spring came, the ice melted, and the skates were put away. The window of time in which a person could develop skating skills was relatively small, and it would only be when ice became available year-round that sports such as hockey and figure skating had a chance to flourish.

The indoor ice rink is not as modern as many people might suppose. The first artificially frozen ice rink opened in London in 1876, and in 1908 the first Olympic figure-skating competition was held as part of the Summer Games on a refrigerated indoor rink, also in London.

The advances in technology that made indoor ice possible also enabled people to own home refrigerators or air conditioners. In these systems, a compressor is used to liquify a volatile refrigerant such as ammonia, and the refrigerant is then allowed to expand as it passes through evaporation coils, where it absorbs heat from the surroundings as it returns to a gaseous state. When the refrigerant is compressed to liquid form again, the heat is released and vented outdoors.

Michelle Kwan and others know good ice when they spin on it.(Allsport)

In an ice rink, the refrigerant doesn't cool the ice directly. Instead, it cools a brine or antifreeze solution that is pumped through pipes under the ice. In permanent rinks, the pipes are embedded in a concrete or sand base. There are also portable rinks -- called "tank ice" -- that can be set up anywhere. These rinks have their pipes embedded in mats that are assembled piece-wise to form the base for the ice.

ONCE THE REFRIGERATION PLANT has cooled the base down to a sub-freezing temperature, the next step in making ice is to add water. This is not always as simple as it sounds.

At the 1999 U.S. Figure Skating Championships, skaters complained that the ice at one of the practice rinks had a "sticky" feel to it and dulled their blades. The problem was that the ice had been made with water that contained dissolved alkaline salts. To counteract such problems, rinks might need to use water purifiers or add chemical conditioners to the water that comes out of the tap.

The water is applied in layers to gradually build up a surface an inch or two thick. A surface that's too thick requires more energy to keep frozen, and is prone to getting mushy on the top. But if the surface is too thin, it is also dangerous because skaters might make "divots" when jumping that go all the way through the ice. This could be especially disastrous on tank ice or rinks built on a sand base, because the skater's blade can potentially puncture one of the pipes that's used to circulate the coolant under the ice.

As the ice surface is built up, it's usually painted to a uniform white or blue background color, along with logos and hockey markings. Contrary to popular belief, the ice itself is painted, not the surface underneath it. The paint is then covered up with more layers of ice so that it doesn't interfere with normal skating. The whole process of making an ice surface from scratch takes about 24 hours.

How the ice surface turns out is another story. For figure skating, the ideal temperature for the ice is between 22 and 24 degrees Fahrenheit, while for hockey it's kept a little colder, about 16 degrees. The warmer ice is softer and grips the skaters' edges better, plus it's less prone to shattering on the impact of jumps.

HOCKEY PLAYERS, HOWEVER, PREFER colder, harder ice because the surface doesn't get chewed up as quickly with many skaters on the ice at the same time. Such ice might cause players to lose their edge during a crucial play. Many NHL players were concerned about ice conditions in Dallas during the Stanley Cup playoffs because the outside temperature was hot enough to affect the temperature inside the building, thereby softening the ice.

Another common misconception is that skaters skate on ice when they actually skate on water. In fact, the pressure of the skater's weight concentrated on the small area of the skate blade melts the top layer of ice directly beneath it. This layer of water acts as a lubricant so that the blade can slide easily over the ice.

But no matter how well-made the ice is, it will eventually get rutted and pitted, and dust and dead bugs will land on it. The ability to quickly and effectively resurface the ice is a breakthrough as important to skating as the development of indoor ice itself.

In the "old days," ice was resurfaced manually, using scrapers and a hose and squeegees. This was a time-consuming and labor-intensive process, which could take three or four workers over an hour on a full-sized rink.

All that changed in the 1940s when Frank Zamboni, one of the owners of the Paramount Iceland rink in California, began to experiment with building machines that would shave, scrape, wash, and squeegee the ice surface all at once before putting down a fresh layer of water. The first functional Zamboni resurfacer was put into operation at Iceland in 1949. The next year, Sonja Henie -- the wealthiest and most famous professional skater of that era -- saw the machine in action and ordered two more for her own touring show.

EARLY ZAMBONIS WERE BUILT by hand, on top of a complete war-surplus Jeep. Nowadays, ice resurfacers are mass-produced, and every rink has at least one. Professional hockey teams routinely use two machines to cut down on the time needed to resurface the ice between periods.

Perhaps the greatest mystery of all is what goes on inside a Zamboni, and that process hasn't changed much over the past 50 years.

A blade at the back of the Zamboni shaves the ice, and the scrapings are picked up by horizontal and vertical screws and carried into the large bin at the front of the machine. Behind the blade, wash water is sprayed onto the ice and then vacuumed up again. Finally, a thin layer of hot water is applied to make the new ice surface. The hot water loosens the crystal structure of the old ice underneath, so the new ice will form a solid bond with the old, instead of a separate layer that chips off easily.

This process might be hard to envision, but it certainly beats waiting all year for the pond to freeze.