I noticed that ice cream melts faster in a glass or ceramic bowl than when I put it in a plastic bowl.
So I got curious and did a little testing. It seems that ice cream melts faster to slower in this order:
Stainless – Glass/Ceramic – paper – plastic.
I’m no scientist and this “test” was not strictly controlled so I might be wrong.
But is there a scientific reason why frozen dairy milk melts faster when it’s contacted to certain materials?
In: 3
Some materials conduct heat better than others. You pretty much figured out which ones are good conductors (will quickly heat up the ice cream) and which ones are bad conductors (will slowly heat up the ice cream)
This is also the reason why steel feels cold to the touch and plastic feels warm – the steel is quickly conducting heat out of your hand and the plastic in doing it much more slowly
Mass mainly, not to mention insulation. Paper is low mass plus a good insulator, so it holds little heat and doesn’t conduct heat very well either.
Glass on the other hand has much more mass as well as conducting heat. If you put cold ice cream in a room temperature bowl, the bowl will dump a lot of heat into the ice cream. Conversely, if you put the bowl in the freezer for a few minutes first, it will be cold and help keep the ice cream cold.
It’s very good that you actually did put your ideas to the test and got results. Even unrigorous results are still results.
Now onto your question, it’s because most of the heat is coming into the icecream through the surface of the bowl. Air is a terrible thermal conductor so it factors in very little. From there you’ve ranked the materials by thermal conductivity, plastic being very insulating while metal being very conductive.
If you are interested in continuing your little material experiment, put each type of bowl in the freezer so it starts at the same temp as the ice cream. When something has good insulation, it will keep an item at the temp it started at. So if one of your materials is a good insulator, it will melt the ice cream faster when all the bowls are at room temp, but will melt slower when all the bowls are at freezer temp
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