AIR
'(<a href="http://www.j-archive.com/media/2007-11-21_J_27.jpg" target="_blank">Jon of the Clue Crew performs an experiment.</a>) In the egg-in-a-bottle experiment, the flame going out causes a vacuum effect, so the egg is <a href="http://www.j-archive.com/media/2007-11-21_J_27a.jpg" target="_blank">sucked</a> in by the differential in this between the inside & outside of the bottle'
air pressure