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Weired Ice Cube - How'd it happen?

  1. Dec 16, 2012 #1
    been an ice cube maker for many years now :tongue2: and have never seen this happen before.

    I imagine air was trapped water was starting to freeze and forced the air out at the same time as freezing, but all seems pretty coincidental for two cubes to do this.

    Anyone know how this happened?


    And yes it doesn't take much to amuse me. :smile:
  2. jcsd
  3. Dec 16, 2012 #2


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    Staff: Mentor

    Hey, I've spent HOURS wondering about stuff like that... What do you think makes people want to be scientists in the first place? :smile:

    Interesting that the ice cube in back is doing the same thing, although a bit less spectacularly. My best guess is that there is some condition that caused most of the top of the cube to freeze hard and deep while a spot in the center didn't freeze as deeply as quickly. Then as the water in the center expanded (water is weird, expands as it cools towards freezing) the increasing pressure forced water up through the weak spot, freezing as it went.

    But that's a guess.
  4. Dec 16, 2012 #3
    A great guess, must of been how it happened. But yea, specially odd the one in the back did the same thing.
  5. Dec 16, 2012 #4

    D H

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    They're called ice spikes.

    Nugatory has the explanation pretty much right.
  6. Dec 16, 2012 #5


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    I don't get it. There had to be some special conditions that did not hold for the others, and for almost all other ice cubes. I've never seen that. Like there had to be a small warm spot under that particular cube tray, or maybe a small, warm high-heat capacity object in the tray. Why does it go off at an angle? Maybe its an icicle, formed by dripping water from above? Was the tray tilted in the freezer?

    To get to the bottom of this, we have to make ice spikes reproducibly and make no ice spikes reproducibly. I doubt that it is simply a random event.
  7. Dec 16, 2012 #6


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    Gold Member

    Cal Tech has a wonderful explanation, and preferable conditions to get them to form.


    The freezer needs to be at -7.5C.
    Use distilled water.
    A fan is better.
    Longest spike created was 2.2 inches long.

    Now I know how to make spiked ice for my next party!
  8. Dec 17, 2012 #7


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  9. Dec 17, 2012 #8
    Spiked Ice...Nice!

    So it must have been the temperature that was just right. most of the other cubes in the tray were not completely frozen, still had liquid water in the middle of them.

    Maybe they would have become spiked ice if I had removed them from the freezer.

    Is just city treated water, so not distilled...must be the other rare circumstance...comparatively "pure" water.

    glad to see my spike was average size :tongue2:
  10. Dec 17, 2012 #9


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    There's a Wikipedia page http://en.wikipedia.org/wiki/Ice_spike

    I guess you need distilled water so that the water freezes at the surfaces, from the outside in. Impurities form nuclei and the ice freezes around them, the freezing occurs throughout the volume of the water. Cool (no pun intended).
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