The "whoosh" bottle demonstration is aptly named. Ethanol is vapourized inside a large water container.  The bottle is stood on its base and the fumes are lit from a safe distance.  As the vapourized ethanol combusts, the rapidly expanding gases escape through the narrow mouth of the bottle with a characteristic 'whoosh' sound.  The whoosh bottle essentially mimics a rocket engine. Chemistry students can measure the amount of ethanol combusted and the amount of water produced to determine the reaction efficiency, while Physics classes can strap the bottle to a skateboard and measure velocities and accelerations with various combustible fuels.  Check out the School Videos for a look at the "Whoosh Bottle".