Ceiling Fans: Backward, Right?

Ever ridden in a cold-air balloon?

Hot air balloons are based on a very basic scientific principle: warmer air rises in cooler air. Essentially, hot air is lighter than cool air, because it has less mass per unit of volume. A cubic foot of air weighs roughly 28 grams (about an ounce). If you heat that air by 100 degrees F, it weighs about 7 grams less.

I think we're both right and I love the reference to R & B, they're my favorites. I forgot about Upsadasium.

Cold air is more dense. Add gravity and one gets more weight. Cold air is heavier than warm air. Or for a more interesting physics discussion, I like this explanation:
According to statistical mechanics, where air has greater kinetic energy it has a greater probability to occupy a higher gravitational potential than less energenic air. That is, the system tends toward maximal entropy.
http://www.physicsforums.com/archive/index.php/t-32331.html

http://travel.howstuffworks.com/hot-air-balloon.htm
http://ezinearticles.com/?Why-Does-Cold-Air-Fall-and-Warm-Air-Rise?&id=302338

Lot's of differing opinions to be sure.