Learn how to make oobleck with this simple recipe of cornstarch and water! Oobleck is SO FUN to play with and it’s a great science experiment for kids involving non-Newtonian fluids and viscosity.
Have you ever heard of oobleck?! This substance gets its name from a Dr. Seuss book, Bartholomew and the Oobleck. In the book, Bartholomew has to rescue his kingdom from a sticky green substance that falls from the sky.
You can make oobleck with only 2 pantry ingredients: water and cornstarch (aka cornflour). It’s a simple science experiment that’s somewhat similar to slime, but it’s a LOT easier to make and to clean up.
Oobleck is a substance known as a non-Newtonian fluid (read more on that below!). Have fun playing with this unique mixture and watching it change from a liquid to a solid right in your hands.
Check out our How to Make Oobleck video tutorial:
*Note: Scroll down for the step-by-step photo tutorial.
Looking for fun slime recipes? Here’s a few of our favourites:
Here’s what you’ll need:
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The full printable instructions are at the end of this post, but here’s a list of products on Target that are similar to the supplies we used:
What’s the science behind oobleck?
Oobleck is a non-Newtonian fluid, meaning it’s a liquid where the viscosity (the thickness, or how fast or slow it flows) changes depending on pressure. This is different from a regular fluid, like water, where the viscosity (or thickness) always stays the same.
Oobleck is an example of a dilatant fluid, which hardens when shear (stress/forceful impact) is applied, and softens as the force decreases. In other words, it becomes a solid when you press on it and a liquid when you let it flow on its own.
What can I do with oobleck?
Drag your finger through the oobleck at different speeds. Grab it with your hand and make a fist: feel it harden, and then flow back into the bowl as a liquid when you let it go.
Hit it with a potato masher at different speeds as well. What happens when you smack the surface versus placing it in gently? Do the same thing with a spoon.
You can even try placing the bowl of oobleck on a subwoofer and playing low frequency tones to make the oobleck “dance” around. (Full disclosure: we tried this on a speaker and couldn’t get the oobleck to move, but other people online seem to have had success!)
How to Make Oobleck
- 1 cup Cornstarch
- 1/2 cup Water
- 5 drops Food colouring
- Add 5 drops of food colouring to 1/2 cup water.
- Stir the water and food colouring together.
- Add the coloured water to 1 cup of cornstarch.
- Mix the cornstarch and water together with a spoon.
- If the mixture is too dry and difficult to stir, add a bit more water.
- Stir the mixture until it has a consistent colour and smooth texture. It should be easy to stir when you get moving, but will feel difficult and stiff when you stop moving.
- Your oobleck is complete!
How long does oobleck last?
Oobleck only lasts for 1 day, 2 maximum if placed in an airtight container (you can add a bit of water to refresh it). After that it will spoil and should be thrown away.
How can I clean up the oobleck?
Leave the oobleck out in open air and it will harden overnight. Then you can compost it or throw it in the garbage. (We don’t recommend pouring it down the drain.)
Leave any mess to dry up, if possible, and it can easily be swept or vacuumed up.
Try adding different amounts of water to the oobleck to see how the mixture changes. Learning how to make oobleck is part science experiment and part slime recipe – making it is such a fun sensory activity!
Here’s even more fun slime recipes:
Our book Low-Mess Crafts for Kids is loaded with 72 fun and simple craft ideas for kids! The projects are fun, easy and most importantly low-mess, so the clean up is simple!