When a curler releases the stone, it rotates slowly which causes the path of the stone to bend. The reason has to do with a difference between the way the front and the back of the stone interact with the ice. The reason this happens is subtle. One explanation is that the front of the rock feels more downward pressure, which tends to bend its path in the direction its spinning.
Vigorous sweeping in front of the stone warms the ice, which facilitates melting, thereby lengthening and straightening a shot.
The stone’s concave bottom means it sits on a relatively narrow ring on the pebbled ice surface, keeping points of contact – and therefore friction – to a minimum.
TEXT BY IVAN SEMENIUK, GRAPHICS BY TRISH McALASTER / THE GLOBE AND MAIL