Take an unused tea bag ([wrinkles her nose] something icky like licorice) and empty it of its contents. (Just take out the staple, and unfold it.)
Open it up so that it will stand upright, as a cylinder.
Light the top of it on fire with a match or lighter.
and then shwoosh!!!
Up it goes into the sky.
Have another one ready for back up, ’cause they’ll probably wanna see it again. And again.
How it works: “Everyone knows that hot air rises and this experiment demonstrates that idea as well as the principles of convection currents. As the tea bag burns, hot air is being created, as well as a thermal, or convection current, under the bag. When the tea bag burns down into a small enough ball of ashes, the convection current causes it shoot up in the air.”
[Quoted directly from Steve Spangler Science.]