Between heat & cold which prevails

[C. McAlexande]

I have a heated room beside an unheated garage. If I open a door between the 2 spaces does the heat go out to help warm the unheated garage or does the cold enter the heated space for cooling the heated room?

 

[MagnetDave]

You have a conceptual issue here:

There is no such thing as "cold." This is merely an issue of how your body perceives temperature. Think of it this way:

If I connect a warm room to a less-warm room what happens? Obviously the heat flows from the warmer room to the less-warm room (though a combination of mechanisms) until the two reach the same temperature.

 

[HallsofIvy]

First, of all, while there is a quantity called "heat" (the average kinetic energy of the air) there is no quantity called "cold". "Cold" is simply the absence of "heat". That is, the only thing that could move from one place to another is "heat".

More specifically, the faster moving molecules of air from the warmer room move into the colder moving room faster than the slower moving molecules of air move from the colder room to the warmer. So again, it is the "heat" that is moving.

(This reminds me of the old joke, "Which is faster, heat or cold?"

Answer: "Heat, because it is easy to catch cold!")

 

[Danger]

(This reminds me of the old joke, "Which is faster, heat or cold?"

Answer: "Heat, because it is easy to catch cold!")

Believe it or not, I've never heard that one before.