Let there be a room that can be considered an isolated system at a certain temperature, say 25°C. The outside is a heat reservoir of 10°C.
I know that due to the laws of thermodynamics, if I allow the systems to come into contact and allow thermal transmission, the room's heat will transfer to the outside until it is at 10°C too.
However, I don't understand how it actually happens. Once I open a window, for example, how does the air in the opposite side of the room know that a window has been opened, and move its heat outside?