I left a water bottle in the freezer for it to cool since it was warm, so I could drink it sooner. After a couple hours I forgot I put it in there, so I opened the freezer, and to my surprise it was not frozen. But when I took it out, after 2 or 3 seconds, it froze from the bottom up over about 1 second.
Why did it not just freeze in the freezer? Why did I have to take it out of the freezer first?