You press the button, and cold air starts blowing out.

But where did that cold air come from?

Was it hiding inside the air conditioner?

And if the room air was hot a second ago, how can it come back cold?

The strange part is that the air conditioner might not be bringing new air at all.

It may be taking the same room air, removing heat from it, and sending it back colder.

So the real mystery is not where the cold air was.

It is where the heat went.