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-   -   Why ice melts in water (https://www.askmehelpdesk.com/showthread.php?t=505108)

  • Sep 6, 2010, 01:28 AM
    cnudasharadhi
    Why ice melts in water
  • Sep 6, 2010, 06:04 AM
    Unknown008

    Ice would melt irrespective of it's position, provided certain conditions are met.

    Those are:
    1. A sufficiently high temperature is reached.
    2. A sufficiently low pressure is reached.

    At atmospheric pressure, the temperature at which ice melts is . Since water is warmer than ice, and at a higher temperature than , the ice absorbs heat energy from the water to melt.

    Does this answer your question? :)
  • Sep 6, 2010, 06:51 AM
    DrBob1
    Re condition Number 2: Because water expands when it freezes, ice MELTS when compresssd. Another unusual property of water!

    Unknown008, you're from Mauritius - you have never made a snowball, have you? You take a handful of snow, squeeze it tightly and, voilą, a sturdy ball of ice flakes. If it is really cold you can't do it because it too cold to get below the melting point by squeezing and so it stays a powder.
  • Sep 6, 2010, 07:24 AM
    Unknown008
    Yes, never seen or touched real snow in my life :(

    I never thought about that... and thought that the behaviour was similar to that of liquids when they evaporate... nice, thanks! :)

    I did some research, and yes, you're right.

    I've only seen the phase diagram of carbon dioxide, and I looked for that of water.

    Under a fixed temperature, ice would either melt or sublime if I understand the graph well.

    EDIT: Forgot to add "as pressure decreases" to my last line.

    http://upload.wikimedia.org/wikipedi...-diag2.svg.png
  • Sep 6, 2010, 10:30 AM
    DrBob1
    You are correct in your interpretation of the slope of the solid/liquid phase boundary (the dotted green line). I wonder what the solidgreen line is? Maybe it is the normal liquid behavior. I have never seen that before. Where did yhou get this graph?

    No snow -- the drawback to living in a tropical paradise!
    Next January, go to the beach while I am shoveling my driveway and sidewalks and you will know the pleasure of living in a tropical paradise!!
  • Sep 6, 2010, 10:34 AM
    Unknown008

    Lol, I got it from wikipedia, one of my favourite sources of information :)

    I googled Phase Diagram Water and first came wikipedia.

    Well, I'd be at sea in November... my first cruise. It's got an awesome promotion, so my mother is taking this opportunity.

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