Liquid? Solid? Slimy snot?
A slime-y experiment excerpted from Joy Masoff’s Oh, Ick!: 114 Science Experiments Guaranteed to Gross You Out (with Jessica Garrett and Ben Ligon).
Liquid or solid? Check out this awesome non-Newtonian slime. Some very silly scientists have even filled entire swimming pools with this stuff just to experiment and play with it. You can actually run across these special fluids, but only if you move fast enough. Slow down and you will sink into a giant pool of goo!
Non-Newtonian Slime Ick-sploration
- ¾ cup cornstarch
- 1/4 cup water plus 2 to 3 tablespoons more water
- Small bowl
- Spoon or your hands
- Green food coloring (optional)
- Mix cornstarch and ¼ cup of water in a bowl with a spoon, or with your hands for an ickier feel. Save those last 2 to 3 tablespoons of water and add them one by one, stirring as you go, until all the cornstarch powder is wet. It should feel hard when you try to mix it, but then get gooey when you let go.
- Squeeze it through your hands and enjoy. Notice what happens when you squeeze quickly versus when you just let it ooze. Take a spoon and jab it into the bowl. Or scrape the flat end across the surface. Use the flat of the spoon to hammer down on the ooze. Try punching it with your fist. What happened? Now try lifting it out with your fingers, letting it ooze between them. Now jab your fingers back down in the bowl. What happens?
- Experiment by adding more water, or adding more cornstarch.
- Color it yellow or green or whatever color suits your fancy. Pop a glob onto a tissue and pretend you just picked a giant booger!
- When you are done playing and need to dispose of this slime, put it in the trash or on the compost. If you pour it down the drain and then follow it with more water . . . that pressure could turn it back into a solid and plug your drain!
What Just Happened?
This slime (often called oobleck) behaves like both a solid and a liquid. Not only is it a non-Newtonian fluid, but it is also known as a colloidal suspension and a polymer. The cornstarch molecules don’t dissolve in the water. They simply hang out—suspended throughout the water. As they hang there, they’re all feeling a little antisocial (technically they “repel” each other). If they could talk, they’d be saying, “Hey, man, give me some space.” But when they feel the pressure of a tap from your hands, the cornstarch molecules in the water join together and briefly act like a solid wall. When you don’t apply pressure and simply hold some in your open palm, there is enough water to allow the cornstarch molecules to glide past one another as a liquid would, and they go back to hanging out in their own personal space.
Think of the cornstarch molecules as being a big bunch of fuzzy gorillas all hanging around, eating bananas. If you run straight at them, screaming and flailing your arms, you’ll run right into a big hairy wall of angry primates who want to stop you from ruining their fun. (In the cornstarch, your hand gets stuck because you didn’t give the molecules time to get out of the way.) But if you crawl very slowly and quietly toward the gorillas, you just might be able to slip past them without being noticed. In a similar way, your fingers will slip through the cornstarch molecules when you move very slowly.
Want more slime-y experiments? Check out the book.
About the Book:
From the bestselling author of Oh, Yuck! and Oh, Yikes!, with over 1.25 million copies in print, here is an A-Z compendium of hands-on grossness.
Featuring 114 interactive experiments and ick-tivities, Oh, Ick! delves into the science behind everything disgusting.
Stage an Ooze Olympics to demonstrate viscosity and the nature of slime. Observe how fungi grow by making a Mold Zoo. Embark on an Insect Safari to get to know the creepy crawlies around your home. And learn what causes that embarrassing acne on your face by baking a Pimple Cake to pop—and eat. Eww!