When I eat hot pizza or a melted cheese sandwich, the cheese feels a lot hotter than the crust or bread: in particular, the cheese might scald the roof of my mouth. but the crust will not. Is this
- my imagination, or
- because the crust cools a little faster than the cheese, so has already cooled a bit by the time I eat it, or
- because the cheese cools a little faster than the crust, so transfers heat to the roof of my mouth a bit more, or
- what?
Best Answer
Two reasons:
the cheese has a higher specific heat capacity than the crust;
the cheese has a higher thermal conductivity than the crust.
When you cool a given weight of cheese or crust from the oven temperature to your mouth temperature, the amount of heat it gives up depends on its specific heat. So the cheese, with its high specific heat, gives up more heat than the crust and hence heats your mouth more. The cheese also conducts heat better so it can deliver the heat to your mouth more quickly, and again this makes your mouth hotter.
All of which is fine, but actually it may simply be that the crust cools faster than the cheese while the pizza is sitting on your plate. I can't say if this is the case because I've never done the experiment!