Blow Their Minds With Just Cornstarch, Water And A Speaker
Slime is an objectively awesome way to distract kids; slime that exhibits sense-confounding physical properties goes beyond awesome and enters into, “We just blew an entire rainy afternoon bugging out in the kitchen” territory. And that’s why you need to make a dancing oobleck.
Named after the bizarro slime that falls from the sky in Dr. Seuss’s Bartholomew And The Oobleck, it’s a solution of cornstarch and water that acts like a fluid under some circumstances and a solid under others – “non-Newtonian,” in the scientific parlance.
Oobleck is the gift that keeps on giving; mix it up in a bowl and your kids can run it through their fingers like normal slime, but when they try to poke it, it will solidify and resist them. Add some highlighter ink and it will glow under a black light. Place a tray of the stuff on top of a subwoofer playing bass-heavy tunes and watch their little minds get blown. Here’s how …
Mix A Batch: The secret to a good oobleck is a complex mixture of … one cup water to 2 cups of cornstarch. If you want to make larger batches, you’ll need to … just keep that 2-to-1 ratio. Then stir it with a spoon until smooth. Seriously, this is the simplest cool thing you’ll ever make.
Break Open A Highlighter: Regular food coloring works to color your oobleck, but a colored oobleck is < an oobleck that glows under a black light. Remove the back of the highlighter with pliers and take out the sponge that holds the ink. Use the box cutters to slice the sheath around the sponge.
Color The Oobleck: Squeeze the ink sponge into your bowl and mix just enough that it streaks through. You don’t have to do this with multiple highlighter colors, but you should.
Play With It: Before you go any further, have your kids squish the oobleck through their fingers. It will solidify as they apply pressure and liquefy as they release it. This will freak them out a little, in a good way.
Prepare The Oobleck To Rock: Lay your subwoofer on its back so the cone faces up. If the cone is large enough to hold the oobleck, wrap the whole speaker in plastic wrap so the cone becomes a bowl; if it’s too small for that, pour the oobleck into an aluminum tray and place it over the cone (you may need to secure it with tape, but do so lightly so you don’t dampen the vibrations).
Prepare The Room To Rock: Replace the room’s light bulb with your black light. Explain to your kid how much cooler your freshman year dorm room was than everyone else’s because of black lights.
Rock: Crank some tunes. You want something with a repetitive beat and a lot of bass, preferably in 20Hz and 60Hz range. Since you probably don’t have any way to actually measure that, just put on some dubstep and wait for the drop. This will freak your kid out a lot, but also in a good way.
Coax Your Oobleck: Once the solution is vibrating, it will begin dancing. Use a spoon to push it in to the center of the subwoofer, which will enhance the effect.
-What A Non-Newtonian Fluid Is: Or, at least, what it does. The defining characteristic of non-Newtonian fluids is a variable rate of viscosity. That might be a little over their heads, so just point out a few other common examples – like Silly Putty, or your gut.
-The Science Of Sound: The “dancing” parts of the oobleck are actually standing sound waves moving through the solution. So you can tell them they’re seeing sound; next explain to them what smells taste like.
-As cool as your dancing oobleck undoubtedly is, it’s even cooler when you see it filmed in super slow motion (fast forward to 2:20):
-If you can’t figure out what music will make your oobleck really dance, start with this dubstep playlist.