This week we made one of our favorite non-Newtonian fluids… Oobleck. Oobleck gets it name from the Dr. Seuss book Bartholomew and the Oobleck where a gooey green substance, Oobleck, fell from the sky and wreaked havoc in the kingdom. It didn’t wreck too much havoc in our kitchen, but it is a messy experiment so be ready. The good news is clean up is easy. Just let it dry and wipe away the corn starch.
What is a non-Newtonian fluid you ask? I’m glad you did! A non-Newtonian fluid is one that when you pour it, it acts like a liquid, but when force is applied, it acts like a solid. Maybe you’ve seen a video of someone running across a huge tub of Oobleck. Here’s one in case you haven’t seen it before.
We didn’t have enough corn starch to make an entire pool of it, so we had to settle for a bowl full.
Oobleck is simple to make. It only takes corn starch and some water.
Put the water in the bowl first, then slowly add the corn starch. We ended up using 2 cups of corn starch to get it to the right consistency. When you start feel pressure when you are stirring, you’ll know you are close.
As it gets more difficult to stir, we just switch over to using our hands and just move into the fun of playing with it.
Josh had some great questions while we were playing around. Mainly he wanted to know why he could “feel the corn starch” when he squeezed the Oobleck. The answer is that when force is applied the particles in a non-Newtonian fluid are forced closer together. In a normal (or Newtonian) fluid, like water, when force is applied, the particles scatter.
Oobleck is facinating and soothing to play with. It’s a great sensory toy for kids. We love making it. As you can see in our video, my favorite thing to do is squeeze it in my hand to make a ball and then watch it flow out between my fingers.
We have a couple more experiments in the line up. We’re gong to have more fun with non-Newtonian liquids and make some slime. Then we’re going to play with purified water and watch what happens when you flash freeze it.
Stick around, it’s going to be fun!