What Is Oobleck?

Thursday, August 16th, 2018

Cornstarch

Oobleck is a non-Newtonian fluid. If you have no idea what that means, then you are certainly not alone. Most people wouldn’t know a Newtonian fluid if they drank it for lunch every day in the cafeteria.

Let’s put this in more understandable terms. Oobleck is a suspension, or a substance that can mimic the qualities of a solid or a liquid. These materials are also classified as non-Newtonian fluids. A Newtonian fluid has a constant viscosity, such as water or gasoline. As you might guess, the viscosity of a non-Newtonian liquid changes. Examples include silly putty, ketchup and, yes, oobleck.

So that brings us back to the question of what is oobleck exactly? It’s a substance made from a mix of cornstarch and water. It can feel like a solid when you hold it in a ball, but it becomes liquidy when you let your hand go loose. It takes the shape of whatever is holding it.

Oobleck got its name from a book by Dr. Seuss, called Bartholomew and the Oobleck. In it, the oobleck is a mystery substance that falls from the sky.

How to Make Oobleck

If you want to make oobleck for your kids, it’s fairly simple. You combine one part water to 1.5 parts cornstarch. If it seems a little too solid, add a few more drops of water. It should get to the point where it tears apart if you draw a finger quickly down the middle but comes back together quickly. Some people add food coloring to the oobleck to make it more appealing to children.

Here are a few things you can do with your kids to learn more about the liquid vs. solid question:

  • Let the oobleck sit in a glass for a few hours. Observe how the liquid and solid separate — this is because it’s a suspension and not a mixture.
  • Stir the suspension with a spoon. Ask your kids to predict how long it will take before it becomes difficult to move.
  • Take turns hitting the oobleck with your palm. Do you notice how hard it feels? Ask your kids why they think it becomes a solid when pressure is applied.
  • Put the oobleck next to a speaker and turn up the sound. Is it loud enough to make the oobleck become less viscous, as it does when you apply pressure?

Disposing of Your Oobleck

When you and your kids have finished your oobleck play time, be sure to dispose of it responsibly. Don’t put it down your garbage disposal. The thick material could cause a blockage. Instead, toss the oobleck into the trash can. You can always make more for another rainy day lesson.

Find More Fun Experiments for Kids

If your children enjoy learning about oobleck, then they may enjoy other science-related activities as well. Bring them to one of our after-school science clubs or science summer camps. We teach kids about science using fun, relatable projects. It’s the perfect after-school or summer treat for kids ages 4-11. Contact us today to learn more about our offerings.