This Physics Girl video highlights seven different surface tension experiments that you can easily try at home or in the classroom. Have any of these around? A plate, a glass, a penny, an index card, a paperclip, an eye dropper, a cup of coffee, dish soap, or some food coloring… and if you’re teaming up with an adult, get a pan and stove, too.
Surface tension is the energy, or work, required to increase the surface area of a liquid due to intermolecular forces. Since these intermolecular forces vary depending on the nature of the liquid (e.g. water vs. gasoline) or solutes in the liquid (e.g. surfactants like detergent), each solution exhibits differing surface tension properties.
Test those properties with a few experiments we’ve enjoyed before — milk fireworks and soap boat — and lots of experiments that we’ve never tried: Surface spheres, floating card, suddenly sinking paperclip, penny dropper, and the Leidenfrost Effect.