The Thermochromic Puck: Hockey’s Latest and Greatest Achievement

The NHL made the announcement yesterday that for the first time, official game pucks to be used in this season’s NHL Winter Classic game will feature a new technology using a thermochromic coating. Thermo-what, you ask?  To put it in the simplest terms, PPG  — yes the Pittsburgh-based paint company that sponsors the Penguins’ home arena and is advertised as the official paint of the NHL — has developed a coating that changes color based on temperature. That’s right — color changing pucks. 

Where have we seen this phenomenon before? Coors Light fans have most certainly seen the blue mountains on their cans and bottles. Or, how many of you owned a Hyper-Color shirt back in the early 90s? Let’s even go back a bit further to the mid-80s and the Freezy Freakies snow gloves? Or how about the color change Hot Wheels cars (I had a red Lamborgini that turned white in hot water)? While the ability to use thermochromic paints and dyes isn’t a new thing, it is for the NHL.

Great strides have been made over the years to improve NHL facilities, players equipment, and enhance the experience for both the players and spectators. With all of these advances in technology and expansion of the game, one of the most important items of hockey that ultimately was ignored, is the centerpiece of the game itself: the puck. That is probably for good reason. Why change something that works; dare I mention the FoxTraxx glow puck?

It’s hard to make an interesting case for a 3” by 1” slab of vulcanized rubber. Although it is the most important item on the ice, like the ball in ball sports, no one generally talks about what kind, type, color, size, hardness, thickness, or anything else related to the puck used in a game. You hear discussions about sticks, goalie equipment, pads, ice surfacing, and uniforms all the time, but usually never about the puck.

Why? Because the hockey puck has generally been manufactured the same since the early era of the game. Yes I know they weren’t always rubber, or even flat, but in the recorded history since I have been alive or anyone currently reading this, it has been the same. Regardless of the manufacturer or the team logos emblazoned on their surface, everyone knows a hockey puck when they see one.

This new idea, at least in theory, is tremendous for advancing the game.  The color change will give referees the definitive visual indication they need to know the puck should be changed on the ice.  For non-hockey fans that have no idea what I’m talking about, lets just say this is a big deal.  Why?

Science!

Hockey pucks are kept frozen for use during games. Freezing pucks helps to eliminate the bouncing effect caused by the vulcanized rubber material and also helps them glide easier along the ice. Think of it this way. Take a rubber ball and throw it against the floor, or wall, or other hard surface. It bounces. Depending on how hard you throw it, it will bounce higher. Essentially, the soft-ish surface coupled with the warm or room temperature of the material causes more energy to be transferred between molecules, hence the bouncing. Now if we drop the temperature of the material, the molecules slow way down, increasing the elastic force, and making it less likely to bounce.

During game play, the puck will eventually start to thaw the longer it is used. Despite being pressed against the hard ice surface for most of the 60 minutes of game play, the constant moving, shuffling, and contact with hockey sticks creates friction and heat, raising the surface temperature. Referees try to monitor this throughout the game, but sometimes can wait a bit too long before replacement. Anyone who has watched a hockey game has noticed that usually a few minutes into a period, or after a long shift, pucks can start rolling and taking strange hops. The coating that PPG developed will be purple when the puck is frozen, but turn clear when the temperature is above 32 degrees. The color change will allow the on-ice officials to easily identify pucks that need to be removed from the ice surface and replaced with “freshly” frozen pucks.

The coating has already been tested and shown to not affect the properties of the puck as it is mixed into the ink used to screen print the various team logos and information on the puck’s surface. The dye used is designed for the sole purpose of being printed on a puck, and if things go well, could see wide spread use in the future. The league will be testing the new pucks throughout the season at various events around NHL but they have not made any comment on whether these will be used in other, official games this season. ■

Tim Parish is a writer-at-large for Puck Junk. Follow him on Twitter @therealdfg.

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Author: Tim Parish

Tim is a hockey nut and music aficionado who, despite a busy life, somehow still finds time for collecting. He's been a sports card collector for over three decades and his collecting habits have evolved many times over the years. Tim has collected all the major sports, but has always come back to hockey and hockey card collecting. It’s a lifelong hobby, so he’s in no hurry and not going anywhere anytime soon. Highly opinionated and never wrong, Tim’s world view of hockey is as keen as any talking head or insider on a major sports network; the only thing missing are the “unnamed sources.” Sarcasm is also his strong suit. You can find Tim and his warped ramblings on Twitter @TheRealDFG.

One thought on “The Thermochromic Puck: Hockey’s Latest and Greatest Achievement”

  1. So basically a few execs were sitting around a boardroom somewhere chatting about what to do next to “innovate” the game. One of them was drinking a Coors light. Then the idea came to them…

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