Stuff I can never figure out

(This doesn't really have to do with goaltending, but with hockey in general... stuff I ALWAYS wanted to know)

Anyone know how they do those beneath the ice crease/lines/logos/etc? What puzzles me is when lacrosse season comes, and they melt the ice, the floor is cement color... do they put a big white sheet over the ice and then flood it? Are the logos on seperate sheets or is it just one big under ice sheet?

How does the Zamboni work? Does it actually "shave" the ice, or merely pour water over it... is that water hot, it seems to steam...?

[Aaron]

check out www.zamboni.com they tell ya how it's done!

[Bryan]

They put down a base layer of ice. Then they paint that layer, and flood on top of the paint to cover it. A paper tape is often used for the lines instead of paint.

Zambonis BOTH scrape down the cut up layer of ice and flood a new one on top. They can be set to do them all at once or one at a time.

[This message has been edited by Bryan (edited September 11, 1999).]

Only the really chep folks use paper tape for their lines, as the color tends to fade out and bleed into the surrounding ice. The point about flooding then painting is correct. My pal is responsible for the MCI Center (Washington Capitals) ice...

Spray with clear ice using many hoses, spray with "white" which is just white paint mixed in the water, paint all logos, lines, circles on the white ice (usually all on one layer), and continue to spray over more clear. Only after a significant amount has been applied by hose/sprayer, can you actually flood with the zam.

As for the lax games, more often than not, they are played when the hockey season is over, so the ice is melted down to the concrete, then the carpet is laid down. FOr those of you in basketball-friendly arenas (same season as hockey), arenas tend to cover the ice with plywood, or some other base, and install the court on top.

As for the zamboni, yes it does shave the ice with one big SHARP blade, but not always. WHen building up the ice (day before games), just water is laid down (flooding), however, between periods, they usually "cut" and "flood" at the same time. Yes the water is hot. Hot water freezes faster than cold, but the explanation is probably better left to TartanBill.

[Bernie]

Hot water does not freeze faster than cold. That is a myth. I've heard this a thousand times and I've even been so daring as to try this experiment at home- and even in the lab. Cold water freezes faster than warm water which freezes faster than hot water.

I think it arose from confusion from the fact that water that has been boiled once and cooled down to its original temperature will boil again faster than it originally did.

Right, Tartan?

Bernie

[daemyn75]

Bernie you are correct as usual. Cold woater freezes faster, but hot water is used to melt the ice and allow it to smooth out the grooves and depressions in the ice. That way you have a nice surface for skating. Am I correct anyone?

[Squealagig]

Ice from boiling water is also stronger as some of the gasses are boiled out so you don't get millions of tiny air pockets but whever it makes much difference or not I'm not certain. Also ice from cold water tends to be cloudy (all those air bubbles again) where as the boiled water is clearer and so that might help increase the visibility of the logos but again I'm not sure how much dirrerence it makes.

[TartanBill]

That hot water could freeze before cold water is something people have said for a long time, and there may be a grain of truth to it.

This would be weird because at some time, the teperature of the initially hot water would have to cool to the the same temperature as the initially cold water! (before passing and getting colder!)

I seem to recall someone tried this out by putting an ice tray each of hot water cold water into the freezer and the hot water would freeze first!

One explanation was that the hot water would steam off a lot of its mass, so that by the time the two trays had reached the same temperature, the hot water trays would be left with less water to freeze. At this point, the two trays have the same temperature, so the tray with less water would freeze first!

Is this true? I don't know for sure, because I havn't tried it. But the explanation can impress your friends!

Note that this would not apply to laying hot water on the ice surface. It would work because the two ice trays are in some kind of thermal equilibrium.

Not that I'm doubting anyone's Physics knowledge, but a very similar question was posed on an exam I took in college...

Freezing air temperature outside, two buckets of the same amount of distilled H2O in each. One at room temp, one boiling. All other factors considered equal, which freezes first?

The answer given was similar to TartanBill's explanation of the hot water losing some mass by excited particles evaporating, therefore less mass freezes faster.

I'll talk to my pal today and see if he's got a better explanation for why he uses hot water.

[This message has been edited by kpmcd (edited September 14, 1999).]

I just found my new favorite phrase of the week...Thermal Equilibrium. I'm not just sure how I'm going to work it into my next conversation with that cute new secretary down in accounting, but I will find a way.

[robbf]

Aww.. come on skitch....if she is really "hot" then you should have no trouble working that line into the conversation ! Sorry I couldn't resist throwing that one in

[Bernie]

Sorry for butting in on the physics front Tartan, but this is maybe the only area of physics I have some experience with.

Tartan is absolutely correct about the "steaming away" of the hot water, thus less to freeze. Certainly enough volume of water would correct for that however (I.E. 1 drop of hot water would freeze faster that 1 drop of cold water but 1 quart of hot water wouldn't)

But the "real" theory is that hot water builds a "cooling momentum" in that, since it has much farther to go to freeze, it's like rolling downhill and it gains this momentum as it cools to a point that its cooling rate shoots past the cold water's cooling rate and thus the hot water freezes faster. There is only one problem with this. It's total bullcrap!

2 Years ago a grad student and I got into this same argument while he was a summer intern in the lab. Figuring I'd teach him a little about his future as a scientist I set up an experiment (geeez, the lengths I go to to prove a point).

We have a -80c (c=Celsius) freezer in the lab (a regular freezer is -20c but then you have to wait 6 hours for results!). This -80c freezer has 4 shelves. All shelves are independently cooled (I.E. the bottom shelf isn't colder than the top one) Also the containers of water were actually wide "trays" which gives the most exposed surface area so the hot water has actually MORE chance to freeze faster than anything.

On shelf 1- 100ml of hot water (90c- almost boiling but not boiling so as to preserve as much volume as possible). The 100ml was measured after the water reached temperature.

Shelf 2- 100ml of 2c ice water
Shelf 3- 100ml of 24c water(room temp)
Shelf 4- 100ml of 45c water (fairly warm)

Results-
The ice water froze solid in about 4 minutes. The 24c water froze solid in about 9 minutes. The warm water in about 15 or so minutes but it didn't yet freeze completely- it was only frozen on the surface.

The hot water? Who cares- it wasn't even close to frozen yet and the point was already proven.

If you ask me, it sounds like anyone with common sense could have predicted the same outcome!

Bernie

That's basically what my chemistry teacher told me last year...

I've heard this hot water vs cold water for ice cubes thing myself, and although I haven't experimented (maybe someone else will) I do have a theory.

If you put an ice cube tray full of hot water in your home freezer, the heat will warm up the whole interior. This will trigger the compressor to kick on trying to chill the whole lot back down to whatever it should be (-20 C?). This constant blast of cold air could result in the water getting to below freezing faster. Whereas, if you use cold water, typically it won't trigger the compressor, therefore no blast of cold air. Guess its similar to the difference between a conventional oven versus a convection oven.

[Squealagig]

Maybe we all have too much spare time if all we can argue about is whether cold or hot water frezes faster.