My physic teacher told a story where he bought some beef, put them into a vacuum (separated), measured their weight and put them into the freezer. Some days later he wanted to cook one of them but he couldn't see a difference between the beefs and his other meats. So he decided to weight them since he wrote their weight down before. Surprisingly none of them had one of the noted weights, he told that they were completely different. His biggest beef weighed about 1.300g but now it weigh less (I can't remember the number anymore).

What's your question?

What could be the reasons that the beefs lost their weights, although they were packed in a vacuum and put into a freezer?

  • This sounds like a homework problem.
    – moscafj
    Apr 21, 2021 at 10:23
  • No it isn't. He couldn't explain it himself so he told us this story and asked us if we knew why the reason. I'm interested into this "phenomenon" as well and I'll send him a link to this question if someone knows the answer.
    – TornaxO7
    Apr 21, 2021 at 10:28
  • 1
    Have you tried repeating the experiment, to see if it happens consistently? Maybe he made some mistake in his recordkeeping.
    – rumtscho
    Apr 21, 2021 at 10:42
  • Well it wasn't an experiment. That happened during his normal day. So now, I haven't tried yet to repeat this "experiment".
    – TornaxO7
    Apr 21, 2021 at 12:13
  • 1
    OK, to state it more precisely: You think your teacher observed a counter-intuitive phenomenon. Before you can find an explanation for its cause, you should prove that the phenomenon exists, by recreating it in a well-documented experiment. There are lots of alternative explanations which do not require the meat to actually have lost weight.
    – rumtscho
    Apr 21, 2021 at 14:50

1 Answer 1


If the outside of the bag was wet (such as if it were rinsed after sealing), that water will have evaporated. There may have been some small amount of outgassing from the plastic itself. Neither of those effects would amount to more than a few grams. If the reported difference was greater than that, the most likely explanation would be measurement/recording error.

  • Ok, so my teacher said that he also thinks that he probably measured both times differently. Anyway thanky you for your answer :)
    – TornaxO7
    Apr 21, 2021 at 19:49

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