Cheers!
Posted on 02/20/2006 10:31:33 PM PST by raygun
Here is one question that probably won't cross the minds of Sasha Cohen, Irina Slutskaya and the other Olympic women figure skaters today, even if they fall: Why is ice slippery?
The explanation once commonly dispensed in textbooks turns out to be wrong. And slipperiness is just one of the unanswered puzzles about ice. Besides the everyday ice that you slip on, there are about a dozen other forms, some of which experts suspect exist in the hot interior of Earth or on the surface of Pluto.
[snip]
Ice, said Robert M. Rosenberg, an emeritus professor of chemistry at Lawrence University in Appleton, Wis., and a visiting scholar at Northwestern University, "is a very mysterious solid."
[the above snipped out of a two page article]
(Excerpt) Read more at nytimes.com ...
Then I was going to post it in culture/philosophy because I have the "Yer Album"
Being a veteran Freep-poster, I understand it is extremely bad form not to perform the perfunctory search to see if its already been posted. Much to my glee I discover that nobody has posted this cool little tid-bit. Moreover, I discovered Blam's post about the same way cool topic as mine.
Enjoy!
ping
Cheers!
''What do you think of it?'' I asked him.
''It's black. What is it -- hell?''
''It means whatever it means,'' said Newt.
''Then it's hell,'' snarled Castle.
''I was told a moment ago that it was a cat's cradle,'' I said.
''Inside information always helps,'' said Castle.
''I don't think it's very nice,'' Angela complained. ''I think it's ugly, but I don't know anything about modern art. Sometimes I wish Newt would take lessons, so he could know for sure if he was doing something or not.''
''Self-taught, are you?'' Julian Castle asked Newt.
''Isn't everybody?'' New inquired.
''Very good answer.'' Castle was respectful.
It is the whitest substance known in that its albedo is uniformly high across the whole spectrum (reflecting all electromagnetic radiation with equal vigor), however, it absorbs IR like nothing else known (and so is a perfect blackbody. Its plausible that I could be wrong on all that (considering that I'm self taught on all that). But that notwithstanding, water is some pretty wonderfully facinating stuff.
E.g. if but for that little density hook thing, no life on this planet could exist (all the lakes would freeze solid ffom bottom up). I'm certain this would cause no shortage of consternation to would-be ice fisherman.
I don't skate but both of my kids play ice hockey. They talk about 'soft' ice & 'hard' ice...soft ice is slow, hard ice is fast and they get their skate blades ground accordingly.
..and the only substance which increases in volume when it freezes.
my 0.02$
Yeah, water is pretty amazing stuff. Without it, life as we know it wouldn't exist. And the probability of it existing in liquid form is very remote. Earth is indeed a privileged planet.
What you said. Even so I've been bronzed by NASTAR (100/1000ths out from the silver in my age group at the time (about 10 years ago), I truly understand what you said. Anybody that knows anything about NASTAR will understand that the benchmark standard doesn't change a whole lot (although some accomodation is given) with respect to age.
One thing that I disticntly remember struggling with: the ruts. The ski-chatter was absolutely fear inspiring. I found out afterwards that those ruts were the prima facie cause for ACL knee-surgury for any serious skier. I like skiing, but I guess I'm not that serious. As in any sport, one has to be willing to give what it takes.
My hat's off to all of these athletes (even the people who finished last). That is most especially appropriate to some of the woman skiers (anybody notice how thick their thighs are?). I'll tell you this with utmost frankness: you gave it your all, and reached Deep INTO yourself to find more and only to find "nothing". That's cool in my book, because you went to the mountain (I didn't).
I know the text-books are wrong, because I've recently become involved in F1 racing simulation. Almost all of the material about tires is wrong. Wider tires does NOT make one faster. Wider tires does something, but not what is conventionally thought.
Anyways, I hope that y'all thought the matter to be as cool as I did. I've read so MUCH cool stuff on this board that my mind swims. Sometimes you just have to give back.
.and the only substance which increases in volume when it freezes.
I know one other that increases in volume when hardened.
Earth is indeed a privileged planet
Yeah that evolution was really thinking ahead.
In addition to its characteristics as ice, it also has some uniques qualities in the high temperature ranges also.
"I don't know rabbit, you might be right"
As steam it can hold extremely high temperatures. It is called super heated steam.
I think that somebody wrote something or another 'bout some cheshire cat (waht I now - I'm merely self taught). Hey, I'm trying to promote some image here (so bear with me even if its not workin').
Oops, didn't mean to step on your shadow. I am rapidly becoming self untaught.
"Latent Heat of Vaporization", look it up and scratch your head a little.
Heat added to Saturated steam (at a given pressure)does nothing to raise the temp of the steam. It merely transfers more steam to a superheated (Dry Steam/No Water Vapor)) state. Only then can heat be added to increase temp.
As an example this would take place in a power plant. Superheated steam would be sent through the High Pressure stage of the turbine where Temp. and pressure is (Used)reduced.
The Superheated steam would then be sent back to the Boiler to a Reheat section. Exhaust/Flue Gases would be used to raise the Temp. of the steam but not the pressure. There would actually be a pressure drop due to piping. Then back to the Turbine through a Intermediate pressure section and then a Low pressure section.
The Temp. increase that takes place in the reheat section contributes to the Enthalpy equation.
Already paid for (Obtained from Flue Gas) these temps. are essential to efficient operations. They really do mean the top end for the plant.
Yea, but you do realize it contains the deadly, corrosive substance monohydrogen dioxide, don't you?
Figure skates and hockey skates have a curved blade. The pressure exerted by them would be much higher, due to the much smaller surface area in contact with the ice. I'm surprised these scientists either don't know this or failed to mention/consider it.
Yes, ice is slippery even in contact with shoes. But compare the two. You will travel much further gliding on ice skates than you will in your wingtips. There seems to be something to the pressure and/or friction angle after all.
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