Quote Originally Posted by Liquidhandwash View Post
I don't know about the numbers But when i was a kid I filled a ballon with acetylene and it fell to the floor fastest then an air-filled ballon. My friend stupidly put a match to it and burned off his eyebrowes
It is possible this apparent discrepancy of density of acetylene may be caused by the balloon itself. The pressure inside a balloon is a bit higher than 1 Bar due to the elasticity of the balloon itself and how much it is inflated.