How much does a stone (rock) weigh?
Stones vary but the average is about 42lbs. For competition they are typically at least 40lb but not more than 44lbs.
What is the point of the brooms/brushes?
The brooms/brushes serve 2 purposes:
- They clear the ice of debris that will cause a rock to “catch” or “pick.”
- They heat up the ice causing less friction, which will allow the rock to travel further and with less curl.
Why is it called “Curling”?
Think of a glass on a table that has condensation under the bottom. Unless the table is perfectly level, the glass will eventually slide/float on that thin layer of water. As it moves it naturally starts to rotate as well. The rotation is caused by less friction on one part of the glass than another.
Just like the glass, when a rock is delivered, it will want to rotate. The rotation over 114ft, will be enough to pull the rock to the left or the right. It will never travel straight. So to be able to know where rock will end up, the curler will put a clockwise or counter-clockwise turn on the stone to control if it curls to the left or the right. Hence the name “curling”.
More information regarding the physics behind how and why a stone curls can be found here.
How much will a stone curl?
Every ice surface is different. Humidity, they way the ice is cut, the amount of pebble, and the temperature can all effect the how a rock will react on the ice. In ideal circumstances, one might expect a stone to curl (move left or right) by 2.5ft over 114ft of ice without sweeping.