Curling is believed to be one of the world's oldest team sports. Though the exact beginning of the sport is not known, there are references to similar gameplay in 16th century paintings and the first written evidence dates back to 1540. In 1838 at the Grand Caledonian Curling Club in Edinburgh, Scotland, the first rules of curling were written. Curling made its Olympic debut in the 1924 winter games held in Chamonix, France.
The area for play is called a rink or a sheet. The first curlers used to play on frozen lakes. Due to the unevenness of a frozen lake, the game was very difficult to play well. It used to take a great effort to just get the stone to the other end of the sheet regardless of trying to aim. Today the game is played on man-made sheets of ice that can be precisely controlled with proper care. A curling sheet is a 150 foot long area of ice with two 12 foot targets set in the ends called the house and footholds called hacks. The houses are the area that the stones are thrown in order to score points.
The key item needed for a game of curling is the stone According to Robin Welsh, Curling Gold Medalist in the 1924 Winter Games, old stones were rough shaped stones that had grooves carved in them as handles The stones used today are 38-44 lb precisely machined chunks of a specific European granite. The bottom has a narrow circle running surface that reduces the amount of stone touching the ice. To play a game, 16 stones are needed, 8 for each team.
Finally the additional tool curlers use is a broom. Originally brooms were made of certain tree branches. These evolved to the more practical corn broom and horse or hog hair brushes. The most common brooms of today have a fabric pulled over the end which eliminates the possibility of corn stalks or horse hair from falling out and getting caught under the stone. According to John Bradley of the University College Cork in Ireland in his study on the science behind curling, sweeping can be a demanding and effective tool. “Curling is the only sport where the trajectory of the projectile can be influenced after the stone has been released." By sweeping in front of the stone, the sweepers are able to change the friction between the stone and the ice and can alter the speed and the curl of the stone. It also moves any possible debris out of the path of the stone.
A curling team consists of four players, the lead, second, third, and skip. In their respective order each player will alternate with the other team throwing 2 stones each. The skip stands at the opposite end of the sheet and tells the player throwing what shot is needed. When it is the skips turn to throw the third takes over the skips responsibilities.
When the skip decides the shot and signals to the thrower what needs to be done, the thrower then pushes out of the hack and releases the stone down the sheet. At this point the skip watches the trajectory of the shot and the other 2 teammates follow the stone, ready to sweep. If the speed of the stone is too slow or if the stone is curling more than intended, the sweepers can use their brooms to sweep the ice directly in front of the stone. In doing so, the surface of the ice is melted momentarily which reduces the friction between the stone and the ice causing it to go farther and straighter.
Once all 16 stones are thrown, the team with the stone closest to the center of the house has won the round, called an end. Then working out from the center additional points are gained for each stone in the house until a stone from the opposing team is closer. Only one team can score each end. This is repeated a total of 8-10 times and the team with the highest score at the end wins.