Cornstarch And Water
Next up is a fascinating substance that is also very easy to make–all you need is cornstarch and water. Get ready to amaze your little ones with Oobleck!
What You Will Need
– 1 cup water
– 2 cups cornstarch
– food coloring
– cookie sheet
– speaker or subwoofer
What You Will Do
Mix the cornstarch and water in a mixing bowl. That’s it, you’ve just made Oobleck.
Now, place the Oobleck on the cookie sheet and rest it on the speaker. You’ll want to drive it with a 55 KHz subwoofer test tone or some bass-heavy music.
You may have to jiggle the Oobleck to get it going or vary the volume.
Check out this video to see it in action.
What is Going On?
Is it a liquid or is it a solid? The answer is both, or neither. It’s actually a non-Newtonian fluid. Confused? That’s ok.
We’re used to seeing materials change properties or phases when we vary their temperatures. We cool water to make it ice and heat it to turn it into steam. Water is a Newtonian fluid, as is air. We won’t get into the exact definition of Newtonian fluids if you’re interested, Wikipedia link can surely help you out. Oobleck is a type of material known as a dilatant or shear thickening fluid. The viscosity increases with pressure.
So, if you move your fingers through the oobleck slowly, it will feel like a liquid. If you hit it quickly with some force, it will react like a solid.
Extra credit- fill your kids’ swimming pool with oobleck. You can walk/run across the surface easily. Stop, and you’ll sink. Awesome!
Want a kit that makes this even easier? Get it here: