What do you get when you combine water, cornstarch, an amplifier and a speaker? (Besides a mess.) You make cornstarch monsters.
Depending on the frequency played through the speaker and the vibrations it makes, the cornstarch will move and dance. Cornstarch is a non-Newtonian fluid which means it becomes a solid when it is under stress and a liquid when it flows. The trick is to find the right frequency that makes the best vibrations to move the cornstarch. You can actually see the sound.
This is a fun activity to take to a friend’s house and borrow their stereo equipment. For more on Cornstarch Monsters, read the experiment.