Why does a very cold coke can freezes when it's open if was liquid moments before?

Very cold means same temperature as the freezer.

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  • 1 decade ago
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    A good question. Usually, but not always, a liquid needs nuclei for ice crystals to start growing on before it starts to freeze. If water is very clean, you can cool it well below 0C before it starts to freeze. But if there's a speck of dust or a bubble, then it will start freezing at 0C. When you open a very cold Coke, the reduced pressure causes bubbles of CO2 to form, and ice crystals start forming on the bubbles.

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  • 1 decade ago

    I answered this exact question before. The link is: http://answers.yahoo.com/question/index;_ylt=AvhyX...

    I think someone who didn't know the answer got a vote so my answer is locked in limbo...please look at it and vote your conscience... :)

    The answer is a simple relationship between the volume inside the can, the pressure of the CO2 in the can, and the temperature inside the can. This in equation form is given by the Ideal Gas Law:

    PV = nRT

    When you open the can, the pressure drops rapidly. The volume inside the can remains constant, the constants n and R remain constant, so the temperature (T) must drop. If the can was just above freezing, then the lower temperature caused by the pressure reduction will freeze the liquid in the can.

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  • 1 decade ago

    The pressure on the liquid lowers the freezing temperature of the coke when the can is closed. When you open it and release the pressure, the freezing temperature goes back to normal, and the coke will freeze if it is colder.

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  • 1 decade ago

    The can contains coke with CO2 disolved and a small amount of free CO2. The contents are under pressure. When you open the can the pressure is reduced two things happen, the free CO2 expands, the disolved CO2 forms bubbles which expand. When a gas expands, it cools. This cools the coke enough to cause it to freeze.

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  • Anonymous
    1 decade ago

    Yeah, beer does the same thing. I'm not a physicist or anything but I think it has to do with the carbonation being released when it's opened.

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