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Imagine you have a pile of snow and a pile of ice shards. You put a soda bottle which has a room temperature into both piles. Which bottle is going to cool down faster?

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4 Answers

up vote -1 down vote accepted

Thermal conductivity of ice is higher than thermal conductivity of snow, so ice is the winner. Ice has higher thermal conductivity because it is more dense than snow. When snow is as dense as ice then it is no longer snow, it is ice.

Thank you for your answers, without them I wouldn't guessed it right :) .

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The first thing to realize is that "ice" is a pile of small ice shards and snow is a pile of itty-bitty ice shards.

Assuming the snow and ice are at the same temperature, the answer to your question with come down to which one has more contact area and (to a much lesser extent) how that contact area is distributed. Also note that the contact area and its distribution could change over time, as the can melts the ice/snow.

You'd have to run the experiment. My guess is that ice would be the winner. This is because ice would maintain a much larger contact area over time. The can in the snow would melt the snow beneath it and drop away from the "snow roof" over it; whereas I would expect the "ice roof" to collapse with the can, continuing to cool it. The can contents in contact with the roof would be expected to be the warmest, thereby giving maximum cooling effect from any contact on the top side of the can.

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Vintage, Don't You agree that one (Fortunatos) small-talk-answer is enough per thread? –  Georg Jun 20 '11 at 19:15
    
Georg, Your bad manners are exceeded only by your bad manners. In most of the places I find a comment from you, it is a negative comment. Furthermore, it is typically extremely rude. Do you treat people like this when you do not have the anonymity of the internet to hide behind? If so, then I pity you. If you are sexually repressed or something, please take that out in some other manner. There is a lot of truth in Fortunato's post; and he expressed it reasonably well. I posted my bit after seeing that you downrated his; so that I could use up some of your downrates. –  Vintage Jun 20 '11 at 19:51
    
that response isn't necessary. Please try to keep it polite even when you believe other users are not. (I'll be deleting this comment thread later once you've had a chance to read this.) –  David Z Jun 21 '11 at 17:00
    
@David --> Read and agreed. Do you not also agree that Georg's comment is unnecessary? And speaking of polite . . . have you read some of Georg's comments? I agree with you totally about polite. That is exactly why I made the comments I made. I have had it up to the eyeballs with the EXTREMELY unpolite things I have read with Georg's signature attached. Not just me, but to many posters. Thank you for listening. –  Vintage Jun 21 '11 at 22:58
    
yes and yes, but that has been dealt with elsewhere. –  David Z Jun 22 '11 at 0:52
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For one you must define room temperature. because if the bottle is worm enough to to slightly melt the show first and then refreeze then this one will cool 1st of not the air in the snow can act as an insulator and this one will take longer. Now the shape and sise of the ice will make a large contribution/small to the surface contact on the bottle this will also make a difference on the air flow around the pieces of ice.

You need to make the experiment MUCH more specific to get a correct answer.

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I relay don't mid being corrected but just vote down my answer. Whats incorrect? Come on please be more polite. –  Fortunato Jun 20 '11 at 10:43
    
> It's Georg. He does it a lot. Don't worry about it. . . If it was wet snow or wet ice, then I would expect the times to be almost identical. Otherwise, variations in starting conditions and snow/ice consistency would affect the outcome. I agree with you that an experiment is in order. –  Vintage Jun 20 '11 at 19:52
    
@Vintage: you don't know who downvoted, and I would strongly discourage you from making accusations... –  David Z Jun 21 '11 at 17:01
    
@David ---> Yes I do know. It is Georg; unless you want to take the position that there is someone else out there who hunts for posts in threads which contain negative comments from Georg and downrates select posts in the thread. The correlation is too strong and the pattern too pervasive to allow for any other conclusion. –  Vintage Jun 21 '11 at 22:55
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This depends on contact area between bottle & ice/snow, and consistency of snow.

If there is not much air in the snow, it should have bigger contact area with bottle, and thus heat will be transferred faster.

Ice will contact with the bottle mainly at shards edges, so contact area is small.

PS. Adding water will change everything, as contact area would be maximized in both cases.

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Add water at 4 degrees C. You'll get water in its most densest form, so you have the most amount of molecules touching the bottle as possible. –  QEntanglement Jun 20 '11 at 8:47
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@Qentanglement : That 4° C water will stay at 4°C? You should have a (or two) looks in a basic physics textbook. Ever heard of laws of thermodynamics, or better, how to make use of them in practical questions? –  Georg Jun 20 '11 at 9:32
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I didn't say that the water will stay at 4 degrees C. You should have a (or two) at what I wrote and didn't include. Yes, its obvious that the water will not stay at that temperature. Why are you pointing out something so trivial and blaming me for not knowing physics? –  QEntanglement Jun 20 '11 at 9:58
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@Qentanglement, weak argumentation. You wrote about 4 °C to fill the highest mass possible, I didnt. –  Georg Jun 21 '11 at 10:23
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