The Whoosh Bottle is an age old chemistry demonstration to show a combustion reaction (and make students jump). The demonstration provides an opportunity to discuss combustion reactions, limiting reagents, and chemical reactions in general.
This fall's under the "Don't try this at home!" category of demonstrations.
For the demonstration a small amount of organic solvent (ethanol is often used) is placed in the container and allowed to evaporate. This is sped up by shaking the container to get the liquid on the sides thereby increasing the surface area for evaporation. The result is a rich mixture of fuel and oxygen gas.
Upon ignition the combustion reaction takes place and you can see the wavefront progress down the bottle. As the reaction takes place the O2 is used up (as well as the ethanol). The reaction then stops due to a lack of O2.
In the video, after the initial combustion reaction, you can see that as air is pulled into the bottle, probably as the gases inside cool and contract, further reaction takes place. This suggests that it is the O2 that runs out (the limiting reagent) and not the ethanol.
To further test whether it was the O2 or the ethanol that ran out, the liquid at the bottom of the bottle after the reaction can be tested. If the reaction went to completion we might think the liquid would be H2O since
C2H5OH + O2 yields CO2 + H2O.
But if we ran out of O2 then the liquid would likely be ethanol. In every demonstration so far the remaining liquid (in a watch glass) underwent combustion when exposed to a flame.
