Add 1 cup of cornstarch and 1 cup of water to a bowl. Stir the two together thoroughly, making sure not to leave any clumps. Slowly begin adding the second cup of cornstarch to the mixture, stirring the entire time. You should now have a substance that will act like a liquid when gently moved, yet act like a solid when force is applied. This is known as a non-Newtonian fluid.

Oobleck responds best to low frequencies, so we’ll use a subwoofer to get the right tones for it to react. A small, powered subwoofer from a home computer system should suffice, although larger ones will get even better results.

If your subwoofer has feet on the bottom, remove those first, then cover it with plastic wrap — this stuff can be messy. Make sure the plastic wrap is pressed gently into the speaker cone to make room for the Oobleck.

Tape the plastic wrap down, then fill the speaker cone with Oobleck until it’s just below the top of the cone.

Download a tone generator app (many can be found on the Google Play store).

Plug your phone or laptop into the subwoofer with the volume on the speakers turned all the way down. While this all can run on one phone, you must be careful not to move it around when adjusting the tone generator while recording your experiments, or you will introduce external values into the measurement.

Start your signal/tone generator app and begin playing a tone.

Start Google’s Science Journal app and create a new experiment using the sound level sensor.

Begin slowly increasing the volume of the speaker until you see the Oobleck begin to clump and move around like a creature from an old sci-fi movie. Stop adjusting the volume and add a note in Google’s Science Journal app at this point. Continue increasing the volume to see how the Oobleck reacts. Now decrease the volume and note when it stops moving.