Whoosh Bottle!

This was always one of my favorite experiments to perform in high school.  The presenter puts a few drops of alcohol into a 20 liter bottle, and drops a lit match inside.  The result is a huge stream of fire that shoots out the top of the bottle.  Not only is this experiment a lot of fun to watch, it has a lot of applications in the classroom.  Obviously, it could be used as an introduction to a chemistry class on combustion reactions, followed by students describing what they observed.  It could also be used in a class on pressure and volume, as when the bottle is ignited, a large change in both occurs.  This can be a somewhat difficult lesson for students to understand, so incorporating an exciting experiment like this one would definitely make the lesson more enjoyable for them.