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Homework Help: Conceptual Question From Stat Mech

  1. Oct 22, 2014 #1
    1. The problem statement, all variables and given/known data

    Why does it take longer to cool water in a refrigerator than it takes to cool air, assuming that the inside of the refrigerator is initially at the same temperature as the room it is in?

    2. Relevant equations

    3. The attempt at a solution
    Quite frankly I don't even know if my intuition for the problem is correct (that wording is verbatim of the assignment sheet). My thought is that the water is a liquid and air is a gas so the gas molecules are bumping into the walls and each other dissipating energy faster than the water making the water cool slower. But I don't see the point of the "refrigerator" in this problem... namely... if the inside of the refrigerator is the same temp as the air in the room, it's just a box.. any help?

  2. jcsd
  3. Oct 23, 2014 #2
    I guess it's kindof a poorly worded question, ambiguous, and I would assume it's trying to ask:
    "If you put a cup, of negligible thickness(say plastic), of water in a frig, and a cup of air in same frig (and somehow kept the air in the cup, e.g., sealed the cup with cellophane), why does it... [...continued as above]?"

    I assume they are sealing the air in with cellophane or it would diffuse out into the cold frig air and come to the frig temp fairly quickly.
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