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I was looking at the ice formed in my refrigerator and found out there were a lot of air bubbles inside it.

The shape of the air pockets seemed strange to me.

There were many small spherical ones and the bigger ones were in the shape of vertical ellipses.

I am not able to understand what's the cause of these different shapes of bubbles.

can anyone explain?

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  • $\begingroup$ When I look into an iceblock, I seem to see bubbles like the OP describes deep in the body of the block. I have been meaning for some years now to use a microscope to measure the depth of some of these bubbles and count their frequency at depth to check whether what seems to be true is indeed so. What do you think? So I don't think Misc. nerdiness's answer is the full story. $\endgroup$ Apr 30, 2015 at 12:41

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If I see this correctly the vertical bubbles seem to be at the top. My guess is that the bubbles were at the top and only surface tension kept the air from being released, when the temperature cooled this surface tension could have been disturbed and the air may have started to escape; this would cause the water to close in from the sides of the bubble but this may have been slowed by the low temperature and the water may have frozen before the hole was closed.

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  • $\begingroup$ When I look into an iceblock, I seem to see bubbles like the OP describes deep in the body of the block. I have been meaning for some years now to use a microscope to measure the depth of some of these bubbles and count their frequency at depth to check whether what seems to be true is indeed so. Pending this investigation, I don't think your answer addresses bubbles at considerable depths. $\endgroup$ Apr 30, 2015 at 12:40
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As water freezes, zones of ice and zones of water form. On the scale of a bubble, the interface might well be a plane.

As the water cools, dissolved gasses form bubbles. A bubble can be engulfed as the interface advances past it.

As ice freezes more gas comes out of solution. The bubble grows. The part that has been engulfed cannot expand. So the bubble becomes elongated.

The spherical bubbles were likely engulfed late, after all the gas had moved into bubbles.

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