Sunday, December 23, 2007

Sunday Potpourri: Ice Is Slippery

Years ago when working out of the Anchorage School District Data Center, I found myself having to rush across to Romig Jr. High to deal with a connectivity issue (the statistical multiplexer's buffer was overrun and wouldn't reset remotely). The school and the Data Center are closely located so I grabbed my jacket and dashed out the door. It was dark and pretty damn cold (no degrees or thereabouts) and my light jacket wasn't much use with the cold wind. So I decided to run; bad mistake that day. About halfway through my 100yd dash I hit a patch of ice and ended up with a compression fracture to my coccyx (tailbone). Yup, ice is slippery. But why? Glad you asked.

I had planned an extensive entry at some point covering the physics of hockey. But I'm lazy and how much can I really say about the primary law of physics involved in hockey. Force = Mass times Acceleration (f=ma). Thats pretty much all you need to know. The faster the stick hits the puck, the faster the puck will go. The bigger the guy and the speed at which he is blazing down the ice to check you from behind the more force you'll feel when he nails you. Describing all that in any kind of detail is just a bunch of math. Way boring. However the one thing that I did learn about the physics of hockey (i.e... why ice is slippery) is pretty cool so I'll share that.

Conventional explanations about ice and it's relationship to hockey said that pressure had something to do with the actions of skates. It was generally believed that the high pressure between the skate blade and the surface created liquid and made the skate blade glide. Not only is that wrong it doesn't explain why a puck glides.

Ice is slippery because the lattice-like structure of the crystals (which gives the ice rigidity) is somewhat mysteriously absent at its surface (see the picture above). Instead there is a "quasi-fluid layer" that exists at the surface. Physicist's have difficulty explaining how and why this situation exists. It clearly isn't a function of temperature since this "quasi-fluid layer" exists at as low as -183F. But even at a relatively moderate temperature of -60F one would find it very difficult to skate efficiently. Apparently, the boundry layer of many (not all) "solid" objects differ from the underlying layers of the object. In ice's case physicists found that the bonds of hydrogen atoms were missing from the lattice structure. Why you ask? To be honest, the mechanisms of the different states of water are surprisingly questioned at the highest levels of physics. We all know that ice melts, but did you know that physicists are only now beginning to understand and record the mechanisms that are responsible. Sure sure you say ... ice melts because it gets warmer and the molecules change state from solid to liquid. Yeah ... you're right in the simplest sense. But follow a couple of the links I've provided and you'll discover a complexity that surprised the hell outta me. Nice, eh? Don't say you never learned anything here.

Tyler Moir of the Drumheller Dragons has been named to the AJHL South Division All-Star team. The game is to be played on January 26th in Grand Prairie. Congratulations to Tyler on this honor. He is currently #7 on the league scoring table with 17g-38a in 38 games for a 1.4ppg average and 3rd overall in penalty minutes. Mickey Spencer's 23 goals with the Cowichan Valley Capitals has him placed at #9 on the goal scoring leaderboard in the BCHL. Since joining the Texas Tornado Gustav Bengtson has 4g-2a in 11 games. Not huge numbers but his .167 shooting percentage is 1st on the team amongst active players. 2 of those goals came in a 6-7 loss to Wichita Falls yesterday. I bet those two teams don't like each other much given that they combined for a whopping 73 penalties in their last two games.

Last week saw a story break that created quite the stir on the Internet. In case you've been in a cave Kyle Okposo jumped off the Gopher ship in favor of starting his career with the New York Islanders. The first interesting result of this news was the huge number of Gopher fans throwing Kyle under the bus for his choice. Then tDon placed the blame on NYI GM Garth Snow when the UofM press release quoted Donnie as saying,
“It is unfortunate that the Islanders put him in a very difficult position."
Apparently, Snow didn't like that much and when Minneapolis press came-a-calling Garth was all about dogging tDon for his failure to make Kyle better. I thought reading all the shitty things Gopher fans were saying about Okposo was funny but then to have this full blown pissing contest between Lucia and Snow topped it. A segment of college hockey fans are all up in arms at this turn of events fearing it'll mean that the NHL will become more predatory and snap up all the best college players in the middle of the season. They're just plain wrong. While I'd agree that it is cheesy for Snow to pull Okposo (or Okposo to bolt depending on your perspective) this isn't the beginning to some significant trend. College hockey isn't suddenly going to become another farm league for the NHL. While the last CBA has created a bit of an exodus from D1 ranks to the pros this Okposo event is more situational than it is typical. Bringing a 1st round draft choice into your college program has this risk. That's just how it is. If you don't want to lose a kid like this then tell him to go play major junior. The Okposo's, Kessel's, Vanek's, Parise's and numerous players before them (and some to come) were never going to be 4 year players. If you don't want to lose players to the NHL then recruit players that will probably be there for 4 years. It isn't like tDon thought Okposo would be a 4 year player. And yes ... I know Okposo did a shitty thing to jump off the boat midstream and leave it up to his former teammates to do all the rowing themselves. It's a risk/reward situation; the Gophers took a risk, they got some rewards for taking that risk and ultimately it went bad. That's life in the big city. All that said, Jeff Dubay should be elected "King of the Whiners" in the upcoming primaries election season. What a putz!

I know everyone is wondering if Bryce Christianson is really coming to UAA. I'm standing by my call that he is. Bryce did dress and play in the most recent Vernon game but the start was given to his backup (Bryce came on in relief and played 14 minutes). His recent absence from a practice as well as being the backup in that game tells me that the Vernon staff is preparing for his departure. The NCAA compliance office is closed for the holidays so all the paperwork to complete Bryce's move to UAA can only be completed when they come back from holiday. If I'm wrong I'll apologize, but I don't have any reason to suspect that I am. We'll know when we know I guess.

Next weekend will see the end of the usual 4 game series between UAA and UAF (next year we go to a 2 game series with both schools hosting a tournament and inviting ... but not playing ... each other). With just a tie either night UAA will wrap up it's second straight Governor's Cup. I'll have previews this week.


Runninwiththedogs said...

I believe you are giving physics, in its infinite wonder, a bad rap. And it's WAY more than just f=ma. Friction, kinetic energy, elasticity... that just scratches the surface.

Donald Dunlop said...


There's no doubt that I gave the overall topic "short shrift"; but as I mentioned: I'm lazy and math bores me (and it all started to seem like "homework" once I delved into it).

Perhaps someone with a better education in the physical sciences will be inspired by my meager attempt and give the hockey world something substantial. I wonder who that could be ... maybe some nuclear physicist ... know anyone who fits that description?

And anyway ... I'd estimate I invested a solid 4 hours researching the "Why is ice slippery" question in order to give it a reasonable answer that could be understood by the typical hockey fan.

Anonymous said...

happy holidays donald and go seawolves



Hey, as someone with a degree in physics I give Donald two thumbs up - great article man!

Donald Dunlop said...

In all fairness RWD was teasin me (and she is eminently qualified to do so).

But thanks for the compliment. ;-)

Official Physics-degreed critiques so far:
1 thumbs up
1 thumbs down (mostly tongue-in-cheek ... I sense)

Donald Dunlop said...

Thanks and to you as well!

Suze said...

Merry Christmas Donald, (and to your dad and daughter as well!)

Suze and Mr. Suze

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