Sweeping

Sweeping in front of a moving stone can affect the path of the stone and is an integral part of the game.  Players who are not taking their turns delivering must be ready to sweep their teammates' stones upon the skip's command.  Friction from sweeping warms up the ice immediately in front of the stone.  Warmer ice produces less "pull" on the stone, causing the stone to travel farther and straighter than it would otherwise.  A pair of good sweepers can not only add several feet to a stone's distance but can also straighten a stone's path.