Freezing a cold bottle of water by slamming it?

  1. Heyas.
    Recently my brother showed me a trick with a plastic bottle of very cold water. It was out of the freezer, pretty cold, but not frozen. He took the bottle and slammed it against the counter and the bottle froze up. I'm at a loss for explaining why this happens.. The only thing I can think of is when its slammed air is escaping the P decreases, allowing T to decrease allowing some of the particles to crystalise.

    Anyone else got an idea?
     
  2. jcsd
  3. Maybe the bottle was a vaccum. In a vaccum the point of freezing isn't as high and the point of boiling is lower, at least I'm pretty sure. Then when he slammed it the vaccum was broken and the water froze.

    I did something similar with a candle. When I put a jar over the candle the flame went out, consuming all the oxygen with it, this created a vaccum. When this happened the warm wax boiled. Although with your situation I may have got it backwards.
     
  4. Office_Shredder

    Office_Shredder 4,498
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    Perhaps it was supercooled, and by slamming it he knocked particles off the sides, allowing the water to freeze.
     
  5. Like slamming a fizzt drink down.
     
  6. I would like to duplicate this trick. Was the bottle completely full? Did it contain only water? Why wasn't it frozen? You've left out a lot of detail.
     
  7. This is extra clear with fizzy drinks as the gas escaping is more evident.
     
  8. Bottle was very much full, contained only water, wasn't frozen because it wasn't in the freezer for long enough. There may have been some frozen water in there, but more was produced when it was slammed.
     
  9. LURCH

    LURCH 2,514
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  10. Thanks for the link, lurch - very cool
     
  11. Office_Shredder

    Office_Shredder 4,498
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    Woah! :bugeye:
     
  12. OlderDan

    OlderDan 3,030
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    How much water actually froze? Was it just water on the surface of the bottle or more? It seems to me that even if you supercooled the water by a couple of degrees, the latent heat released when the water freezes is going to warm up a lot of the remaining water. Every gram of water that freezes is going to give off enough heat to raise the temperature of 80 grams of water 1 degree C. I can't see how more than a few percent of the water in the bottle could freeze, but I can imagine the surface of the bottle being coated with ice. If more than that froze, then supercooling must be draining off a lot of the latent heat without forming crystals.
     
  13. I'd say a small % froze. But it was very noticable.
     
  14. OlderDan

    OlderDan 3,030
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    I used to work with very pure gallium. It will melt in your hand (not advised), or under a lamp, and will stay molten at room temperatures (supercooled). If you touch the molten metal with a solid crystal, you can watch the liquid solid boundary gradually creep as the liquid turns to solid at the boundary.
     
  15. Simple hitting it increase pressure and that made the point of congelation higher
     
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