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Q & A: Ice cubes without bubbles

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Most recent answer: 10/22/2007
Q:
how to made a cubeice whith out bubbles in?
- mary (age 22)
A:
The bubbles in ice cubes are there because air that's dissolved in the water comes out of solution as the water gets cold. If the bubbles are surrounded by ice when they form, they get trapped and remain in the ice cube.

The best way to get rid of air bubbles is to start with water that doesn't have dissolved air in it. You can boil the water first before freezing it, or you can just let it sit out for a while. Water sitting in a jar will have little bubbles of air stuck to the sides after some hours (let it sit overnight or a few days). But just letting water sit all by itself won't get all of the air out -- there will still be some equilibrium amount of air dissolved in the water.

If you really really really want all of the bubbles out, you can boil the water in a container with a vacuum, so that air does not redissolve. Or you could freeze the ice very slowly from the bottom up. That way, the air bubbles can float to the top as they form and not get trapped under ice. This can be done by putting an ice tray on top of freezer coolant coils in an environment that's warmer than 0 degrees Celsius (there may be frost to worry about here, though). The easiest way to get most of the bubbles out is just to start with water with most of the dissolved air out, though.

Tom

(published on 10/22/2007)

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