# Curling Sweeping Rules

Once you’ve mastered the art of releasing a curling stone, there is a good chance that you will need to sweep the stone as it travels down the ice. Sweeping is one of the most important parts of a game of curling, as it can influence the trajectory and final destination of the stone. In this tutorial, we will learn about sweeping and the theories behind it.

## Theories of Sweeping

When a curling stone is swept, the stone curls less and takes a longer time to slow down. This means that the stone travels straighter and farther. There are two theories that explain why sweeping works the way it does, but neither has been proven and declared correct. Below are the two theories.

1. The first theory states that by sweeping the ice, the pebble will be melted, which allows the stone to travel straighter and farther.
2. The second theory states that by sweeping the ice, the pebble is polished, which allows the stone to travel straighter and farther.

## Reasons to Sweep

There are two main reasons why the sweepers need to sweep the stone in a game of curling. They are:

1. Keep the stone on the proper line so that it reaches its desired destination.
2. Make the stone travel farther so that it reaches its desired destination.

## Sweeping For Line

When the sweepers are sweeping for line, they are sweeping so that the stone will curl less and travel straighter. This type of sweeping is necessary if a team is trying to place a stone behind a guard, or if a team needs to hit a stone in a very precise location.

## Sweeping For Weight

When the sweepers are sweeping for weight, they are sweeping to make the stone travel farther. Sometimes, the stone may be light (to slow), and will require sweeping to make sure it can travel the distance it needs. Other times, the weight may be excellent, but require a couple small sweeping adjustments so it stops in its desired location.

Important: Sweepers cannot make a stone speed up, but can reduce the rate that the stone slows down.

## Defensive Sweeping

Now that we have learned about a team sweeping their own curling stones, we will learn about where and when your opponent can sweep your stones out-of-play. The goal of defensive sweeping is to remove an opponent's stone from play, or at least move it farther away from the button. Defensive sweeping is performed like any other sweeping a curler would do on the ice. After one of your team's stones crosses the tee line, a player on the opposing team (often the skip) is allowed to sweep your team's stone. If the stone is moving at a good pace, defensive sweeping can cause the stone to end up out-of-play. Just as your opponent can try to sweep your stones out-of-play, you can try to sweep their stones out-of-play, only if the stone passes the tee line.

## Defensive Sweeping Rules

There are two main rules to defensive sweeping. They are that:

1. An opponent can sweep your curling stone the instant that it begins to pass the tee line.
2. Stones can be defensively swept by one member of the opposing team.

## Defensive Sweeping Past the Tee Line

As soon as one of your stones begins to pass the tee line, your opponent is allowed to sweep. Whether a sliver of the stone or the entire stone is beyond the tee line, your opponent can sweep it until it stops moving, reaches the sideline, or fully passes the backline.

## One Person Sweeps Defensively

After your stone begins to pass the tee line, only one curler from the opposing team can sweep the stone. However, if there are multiple stones that can be swept defensively, an opponent may select one player per stone to sweep defensively. Thus, if two of your stones can be defensively swept, there can be two defensive sweepers on the opposing team, just as long as they are sweeping different stones. This rule extends to three and four stones that can be defensively swept.