Since it is played on ice, ice hockey is popular in Canada and the northern parts of the United States. It is a lot like soccer, but because it is played on ice skates and on a smaller playing area, it is much faster and more violent. For example, it is legal to force another player into the wall of the ice rink. This is called checking. The offense uses a stick with a flat blade one end to try to put a small, hard, rubber disk, called the puck, into the defense's net. Professional hockey players can shoot the puck at over 100 miles per hour, so the goalies have to wear heavy pads and a hard plastic mask to prevent injuries. Hockey is a very exciting game to watch and play.