Help me settle an argument about Thermal bags.
So my soon-to-be-father-in-law and I are having a bit of a disagreement about thermal bags. You know, the kind where you can carry around frozen/hot items and it helps maintain their temperature. He keeps the bags in the freezer, saying that it freezes the air inside the bag to make it stay colder longer. I say, "What? No, that's not a thing."
I did a quick search that yielded no real results, so I'm doing what I always do when I'm in doubt. TO THE FORUMS! You guys are pretty smart. What's the verdict: To freeze or not to freeze?