Agreed it is a great demonstration, and I remember doing a similar one with an aluminum foil boat as a kid. Make a boat out of foil, put it in water, then add a

Agreed it is a great demonstration, and I remember doing a similar one with an aluminum foil boat as a kid. Make a boat out of foil, put it in water, then add a few drops of dish soap behind the boat and watch it "sail." The scientific name for this is the Marangoni effect [0]. 0: https://en.wikipedia.org/wiki/Marangoni_effect https://en.wikipedia.org/wiki/Marangoni_effect