[chezlaw]

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sometimes when i take a .5L bottle of water out of the freezer, it is in a liquid state but when i open the bottle, it then starts to partially freeze. it turns into a slushy, clouded mixture from its usual transparent, liquid state. it seems to develop some ice crystals. i have a feeling the act of opening the bottle may speed up or start this process, but i am not sure because i always open the bottle (no testing of other outcomes)

what is going on

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Just a guess but some of the water turns to gas when the bottle is opened (gas being held in liquid form due to the pressure?). The gas is at the same temp' as the water and some energy is needed for latent heat. This cools the water, ice forms.

chez