Body Heat in a Large Room

So, I was in Chemistry class today, and it was warm enough that I didn't need my fleece (thanks to one of my friends for telling me what it's called). When the end of class came, of course, everyone left. About five minutes later, I noticed that the room was getting cold. (I have three classes in a row in this room, with a 40-minute break between chemistry and Discreet Structures.) Now, my chemistry class is very crowded, with most of the seats full. I could very well be wrong, but I'm going to attribute the temperature change to the people leaving the room.

P.S. I'm filing this under "random" because it really has no point.