I can’t think how to google this succinctly enough, so - will something that is fat based reach the same low temperature as a liquid when chilled or frozen. I know that its structure will be affected differently, but, for example, if you put a fatty cheese and some water in a freezer will they reach the same temperature?
My wife says no, but I’m not so sure.
Yes. Everything radiates its thermal energy into a colder environment until they’re both the same temperature.
The confusion might be that some substances feel much colder than others because they are better at drawing thermal energy from your body at the point of contact. For example, your skin will freeze-burn when touching a cold metal pipe, while it’s safe to touch a piece of wood at the same temperature.
You could also have a difference if you cooled off the object until it froze, and then stopped cooling it. Different substances have different freezing points. But that’s not what the freezer in your kitchen does: If you leave things in it, it’ll just keep on cooling them down until it gets everything inside to whatever temperature you set it at. Ice is at most 0ºC (32ºF), but it can be much colder.
One other factor. Different things give up heat at different rates. If you put some 50 degree water and some 50 degree cheese in the same freezer at the same time, it might take 3 hours for all the water to reach the freezer’s internal temp of, say, -15F. But the cheese might take 2 or 4 hours to get to the same temp throughout.
So if you measured the temp of them both at any time before the slower one got fully cold you would measure them at different temps.
Last of all, the cold “soaks in” from the outside. The cold air in the freezer cools the outer layer of the stuff which in turn cools the next inner layer, etc. Eventually the whole thing becomes uniformly the same temp as the air in the freezer. But along the way each lump of stuff will have a cold(er) outside and a warm(er) inside.
In strict physics parlance the heat flows out rather than the cold soaks in. But many people seem to find the cold soaking in to be a more intuitive way to think of it.
Both of these issues are temporary transitory conditions as the stuff tries to get into equilibrium with the environment. But “temporary” can be long enough that it confuses people about the true end state.
Good answers. Just answering from a different point of view.
Once everything in the freezer is at equilibrium (as in all cooled to the same temperature), no more cooling will occur.
But since different things have different temperatures at which they do freeze, when you open the freezer and compare the condition of things, the fact that some have turned solid and some have not, can make you think and possibly even sense (erroneously) that the still soft things are warmer than the frozen solid things.
I think there are two different questions mixed up in there:
Do different substances have different freezing points? Yes
Will different things in the fridge equilibrate to different temperatures. No.
Everything in the fridge, if you give it enough time, will end up a the same temperature. Whether it will freeze or not depends on the freezing point of the substance and the temp inside the fridge. Most cheese, btw, is already a solid a room temp.