• Question: how is dry ice made

    Asked by eevee to Adam, Sheila, Suzie on 24 Mar 2011 in Categories: .
    • Photo: Suzie Sheehy

      Suzie Sheehy answered on 24 Mar 2011:

      Dry ice is quite easy to make. If you have a pressurised cylinder of carbon dioxide gas, as it comes out it cools down because of the change in pressure – and solidifies.

      To make large amounts though you take CO2 gas, compress it and refrigerate it so it becomes a liquid. Then you change the pressure in the tank and it freezes to a snow-like stuff which you can then compress into the blocks of it that we usually use.

      You need a pretty good refrigerator though to draw all the heat out!

    • Photo: Adam Tuff

      Adam Tuff answered on 24 Mar 2011:

      You make it using carbon dioxide – it’s produced through rapidly cooling it in a pressurised box and refridgerate it, and then you start reducing the pressure – this causes the carbon dioxide to eventually become liquid, then a solid – it’s squashed into balls and voila! Dry ice!

    • Photo: Sheila Kanani

      Sheila Kanani answered on 24 Mar 2011:

      Dry ice is the solid form of carbondioxide, it is a gas at room temp. First you liquify it by putting it under a lot of pressure. Then the liquid carbon dioxide is withdrawn from a tank and allowed to evaporate at a normal pressure. This evaporation uses so much heat from the surrounding air that part of the liquid carbon dioxide freezes to a temperature of -78° C.

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