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Ice formation

  1. Jun 15, 2010 #1
    I would like to know if anyone else has seen this (photo below). I put a tray of purified water in my freezer and by the time it had half-way frozen, inch long ice shards at about a 45° angle had formed, grown right up out of the surface of the water.

    Can anyone point me to an explanation of how that happens?
    I recognize that on every ice cube in this batch, they have lumps and irregular surfaces, but long thin shards are especially weird. I have also seen my ice freeze with a nice flat surface if I am not mistaken.

    http://img21.imageshack.us/img21/8826/224242crop.th.jpg [Broken]

    Uploaded with ImageShack.us
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jun 15, 2010 #2
    Water surface is not at rest due to vibrations from fridge. So at one point, some part of the irregular surface will become ice..then it gradually continues to cool...
    If you cool water in a calm place you might get flat surface.
    Also from photo i notice you kept some metallic spoon which might conduct heat faster than water...so cooling process should be initiated from spoon..and then to water near spoon..it also depends on the sticking force of water to spoon..
    May be if you dont use spoon, then the surface might be smoother..
     
  4. Jun 16, 2010 #3
    Vibrations. Well, that makes sense. Thanks for that insight, but there is no spoon anywhere there. If you click the photo, you can see it full sized.

    I guess that the ice formation of shards has something to do with how ice actually forms at a molecular level. It would seem that once crystals start forming, there is either a pulling of molecules like little magnets lining up or for some reason a higher level change in local water pressure near crystal formation that causes water to want to move up a crystal formation. It would be cool to have an illustration and explanation of what it really is though.
     
  5. Jun 16, 2010 #4

    russ_watters

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    Staff: Mentor

    The ice will form from the sides toward the middle of the top surface, which results in, at some point, a small hole in the middle of the top surface. Since ice is less dense than water, as the ice under the surface freezes (along the surface of the ice tray), some water will get pushed-up and out the hole.
     
  6. Jun 16, 2010 #5
    Oh yeah. That makes sense. One can even see a trail of air bubbles going up the "spout". Though, it's amazing that it can go that far and act that quickly. I do recall noticing, since I pulled it out half-way through the freezing process, that all of the ice was on the top and sides of the "cube" next to the tray surface and the middle was still liquid.
    So, you expand that by many orders of magnitude and you get Superman's ice fortress. :tongue:
    Man, I'd like to get that on video. Hmm.
     
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