Ice hockey pucks are frozen before games so that they slide more smoothly and bounce less.

The longer version

A puck is vulcanised rubber, and warm rubber is slightly soft and grippy, which makes it bounce and tumble instead of sliding flat. Chilling it before a match stiffens the material and lowers friction against the ice, so it skids rather than hops. Freshly resurfaced ice is colder and harder, which helps for the same reason.

Officials keep spare pucks chilled and swap them regularly, because friction and repeated impact warm one quickly during play. A frozen puck also resists chipping when struck. The same logic explains why players dislike a puck that has sat in warm air, and why ice temperature is written into rink specifications.

Where this entry sits

Facts here look at the rules, equipment and odd histories behind familiar sports and games, from balls and rackets to cards, boards and playing fields. Expect small details about scoring quirks, stadium design and the long story of the Olympic Games. The full list sits on the Sports and Games page, where every entry is listed in order.