RE: air density

["John Burk" <joyseydevil@comcast.net>]

My hot air balloon always flew hotter and used more fuel when the humidity was
high - Always assumed that the water vapor didn't expand as much as air when
it was heated - Cars feel faster when it is very humid - I guess the decrease
in oxygen is more than made up for by the richer mixture caused by the extra
fuel the water vapor picks up .