Every plain, paper tea bag conceals an exciting crash course in lift. In a six-second video on Vine, user “oh so tracy” empties a tea bag, folds it into a tube, and lights it on fire. After the bag burns down, the remains of the still-flaming tube flies into the air to create a miniature Chinese lantern. We asked Mark Drela, an aerodynamics professor at MIT, how it works.
Cost: A few cents
Time: 2 minutes
1) Igniting the top of the tea bag warms air inside and above the paper tube, making that air less dense.
2) The hot air rises and draws in cooler air (primarily through the tube’s base).
3) Once most of the paper burns, the tea bag is light enough for the cool updraft to buoy it skyward.
WARNING: Burning paper can ignite other flammable objects, especially indoors. Kids (and pyromaniacs), please seek supervision before attempting.
Watch the results from the original Vine below:
_This article originally appeared in the May 2014 issue of _Popular Science.