The puck is made of vulcanized rubber, three inches in diameter and one inch thick. It weighs about six ounces. Some slap shots propel the puck between 90-100mph. Speeds up to 120mph have been recorded by some of the hardest shooters. Compounding the problem for goaltenders, frequently the puck will curve in flight, much like a baseball.
Many people think that deflections are mere luck.
Actually, players practice deflections constantly, standing off to the side of the nets, or in front, and deflecting the shot from the outside to another area of the cage. Seldom does the goalie have the time to react to a deflection as the puck changes direction off someone else's stick or skate. Not kicked in intentionally, but a puck can be deflected off a skate, or off a player's body if no overt attempt is made to throw or kick it in. There is no score. The puck must completely cross the goal line between the posts to be counted as a goal.