The word "puck" is a derivative of the Old English word meaning "poke." The earliest hockey pucks were usually made of wood from tree branches and eventually evolved to rubber balls, which were awkward and unwieldy on the ice. These ball pucks were unreliable, of course, because they bounced unpredictably.
Eventually someone (and who that someone was is still hotly contested in the hockey world) decided to cut the ball in half and use a flat slice of rubber for a puck. Boston University claims the credit for this innovation, as does Montreal Quebec, Canada.
In any case, the first “recorded” use of a flat disk was in Montreal in March 1875.
In the beginning, rubber hockey pucks were pieces of rubber from recycled tires that were all glued together; however, this construction sometimes caused the pucks to split when they hit a goal post. In 1931 and 1932 the league experimented with a puck made with beveled edges, but that design was ineffective and drew many complaints from the players. The regulation National Hockey League (NHL) hockey puck was designed in 1940 by Art Ross, and the design has not changed much since then.
Today all official hockey pucks used in the NHL are made of solid pieces of vulcanized rubber. The rubber which is shaved off of each puck as it is produced is reused on another batch of pucks. Each black puck is uniformly three inches across and one inch thick. Looks may be deceiving, as a regulation puck weighs only six ounces at the most. The edges around the puck are embossed with a textured pattern, perhaps mesh or diamond shapes, so that the puck will cling to hockey sticks with blades wrapped in tape. Though there are different brands and labels, hockey pucks must be uniform and consistent for use in the NHL.
Pucks are kept frozen during a hockey game because they are much easier to control on the ice. Unfrozen, a puck is likely to bounce or skip on the ice and is therefore much more difficult to control with any accuracy. Often these frozen pucks are kept in a cooler to ensure that they stay frozen until they are used; the average number of hockey pucks used in a typical NHL game is twelve. Fun fact: the hardest slapshot with an official puck has been timed at nearly 120 miles per hour.
Surprisingly, only four countries in the world produce hockey pucks: Canada, China, the Czech Republic, and Russia. As many as forty million hockey pucks are sold every year.
Those who attend hockey games are at a nominal risk for injury from these flying rubber disks as they go flying after deflections, and one death has even been attributed to a hockey puck hit to the temple.