Oobleck! It’s a funny name for an odd fluid that defies general liquids’ properties, which earns it the category of non-Newtonian behavior. The defining characteristic of oobleck is that its viscosity changes depending on shear rate, meaning the fluidity changes depending on how much pressure is put on the liquid. If little pressure is put on oobleck, then it acts more like a liquid, but if great pressure acts on it, then it firms up.
Here’s how you can make your own inexpensive non-Newtonian fluid to play with at home. It’s easy. Really…only two ingredients!
What You Need:
- 16 oz 100% Pure Corn Starch
- 2 3/4 cups Water (For UV-glowing option, use Tonic Water with Quinine
)
- Plastic Basin
)
Directions
Step 1
Pour the corn starch into the plastic basin. Add the water a little at a time, slowing mixing until the oobleck has a batter-like consistency.
Step 2
Play with the oobleck using cups, your hands, a hammer, a strainer or a spoon. You can multiply this recipe and fill a kiddie pool for a party. If you replace the water with tonic water, then it will glow when you shine a Black Light Flashlight
Step 3
Oobleck can be stored in a sealable container and played with again during the week. The corn starch will settle to the bottom, but the fluid can be rejuvenated by remixing it.
Step 4
When you’re done playing with oobleck, I recommend you dispose of it in the garbage or compost. Don’t pour it down the drain because it has the potential to harden in your pipes.
Explanation
The viscosity, or “thickness”, in this non-Newtonian fluid changes depending on how forcefully you put pressure on the oobleck. The corn starch and water mixture may be stirred slowly, but if you stir quickly and forcefully, then the fluid becomes thick for as long as you apply the pressure. Once you stop, it becomes runny again.
There are other types of non-Newtonian fluids that react and change viscosity differently than oobleck. For example, ketchup reacts the opposite way to shear rate than oobleck. Ketchup is a shear thinning fluid, rather than a shear thickening fluid. When you try to pour ketchup, it’s thick and difficult to start flowing, but if you stick a knife in the container the viscosity changes, and the ketchup flows more quickly.
Did You Know? Oobleck gets its funny name from a Dr. Seuss story, Bartholomew and the Oobleck
What fun ways to you find to play with your Oobleck? Share them below in the comments!