The Secret to Making Perfect Hockey Ice
Any hockey player will tell you that the quality of the ice on the rink can make or break the game. What are the secrets to making the rink the best it can be?
Perfectly Smooth
If your ice surface has lumps and bumps, forget about skating fast. If you’re looking for pucks and players to go as fast as they can, you need a super smooth surface. It’s all about minimizing friction! Whether you find it between the ice and the puck —or the ice and a skate blade— friction slows everything down. If you’re looking for speed (and want to avoid snags), you’re looking for a smooth surface... and that’s what Zambonis are for! Between every period of the game, Zambonis scrape away all the imperfections, clean up the icy debris, and cover the rink with a fresh layer of water. This thin later of water fills in all the dents and grooves made by all those skates and then freezes almost immediately for a smooth finish.
What makes it so slick?
A smooth surface is just the first step. More is needed to make it slippery. A glass or a ceramic floor is super smooth, but you wouldn’t get far on those surfaces with your skates, would you? So, what makes ice so slick? Turns out, it’s because it’s made of water. We all know that ice is frozen water, but you might not know that there is a thin layer of water on an icy surface that’s not quite water and not quite ice. It’s gooey and flexible, almost like a thin layer of slush, and that’s where all the sliding happens. The water molecules below the ice surface are frozen and tightly bonded together, but the water molecules you find between the hardened ice and the ambient air aren’t as tightly bonded. That means that these water molecules move around when something comes into contact with them, like a boot or a blade. Think of all those surface water molecules as if they were miniature marbles. These moveable molecules are precisely what makes your ice skates slide… or your boots slip!
An Ice-Cold Puck Please!
Professional hockey pucks are made from vulcanized synthetic rubber. Vulcanization is a special process that heats the rubber to make it more rigid and resistant. Hardening pucks like this makes them easier to handle with a hockey stick, but there’s another secret: NHL pucks are frozen before they go out on the ice. This reduces their friction against the ice surface which makes them move faster, but freezing also makes pucks less bouncy. How many pucks do you think are used during an average NHL game? Answer: 12.
Perfect Ice… It’s All in the Details
Every rink has its own rink maintenance team. At the Montréal Bell Centre, they keep the ice about 5 cm (or 2 inches) thick. To keep the rink in optimal condition, they keep the temperature in the arena between -4°C et -7°C (that’s 19 to 24°F). In the world of professional hockey, rink maintenance is truly an art form... informed by science!
To learn more about all the science behind our favourite national sport, don’t miss the Hockey: Faster Than Ever exhibition at the Montréal Science Centre. It runs until September 10, 2023!
Sources:
La glace comme science
Fine Science, Freezer Temperatures Give Habs Great Bell Centre Ice
Physicists finally worked out why ice is slippery after 150 years
New approaches to the mystery of why ice is slippery
https://phys.org/news/2022-12-approaches-mystery-ice-slippery.html
