Today I’m going to show you how to make oobleck and 10 awesome ways to play with it!

Say the word OOBLECK  (or goop) in my house and my daughter will come running! Oobleck was actually the very first science experiment I tried when I was the science parent at our co-op preschool years ago. I chose it because it’s no fail and always a hit; I mean really, who can resist a slippery, gooey substance that forms a ball when you squish it together but quickly melts into a liquid when you let go?

Oobleck: The best sensory play recipe!

Oobleck is by far my students’ favorite sensory activity. I have seen kids play with it for long periods of time, fascinated with its texture and consistency. It’s wonderful to engage kids in making the oobleck; it gives them a chance to touch and feel the cornstarch before it’s mixed with the water and then to observe how it changes as water is introduced. I highly recommend making a HUGE batch of oobleck with kids in a large shallow bin. Once it is mixed, introduce kitchen objects like spoons, colanders, and sieves for them to play with.

For kids who don’t like to get messy I recommend having large spoons, aprons, and possibly gloves nearby so that they can participate in the fun at their own pace. I’ve had students shake their heads when asked to dip their hands into this weird substance, but poking and prodding at it with a spoon sometimes gives them the confidence they need to finally dip in a finger into the oobleck.

To get a taste of the fun you can have with oobleck check out this video:

What is Oobleck?

Before we start let’s talk about just what oobleck is. Oobleck is a non-Newtonian fluid, a fancy term for a liquid whose viscosity changes depending on pressure. Viscosity is the measure of friction in a liquid and determines how fast or slow a liquid flows. Most liquids have what we call consistent viscosity, for instance honey and water will always flow the same no matter how you pour or press them. Oobleck on the other hand does not have consistent viscosity. If you apply pressure to it, it forms a solid, loosen the pressure and it melt back into a liquid. Because the viscosity changes, it is classified as a non-Newtonian fluid.

In chemistry oobleck is what is known as a colloid, a substance in which small particles of one substance are suspended throughout another substance but not chemically bonded. If fun hands-on chemistry projects sound enticing hop over here to see 50 more…

Is oobleck a solid or a liquid?

It’s actually both! Oobleck behaves like a solid or a liquid depending on the pressure exerted on it.  Press it together and it feels solid, let is sit in your hand and it drips like a liquid.

Is oobleck slime?

When most people talk about slime they are referring to glue based slimes made by mixing white or clear glue with sodium tetraborate (found in Borax, liquid starch, and saline solution). You can read all about the science of slime here. That version of slime is also a non-Newtonian fluid with similar properties to oobleck. The difference is that oobleck tends to be more liquid like and doesn’t last long (it will mold) and glue slime tends to be more solid and can last indefinitely in an air tight plastic containers. I consider oobleck and slime to be cousins!

Now enough of the details, let’s get to the making!

How to Make Oobleck

Oobleck always requires some fine-tuning. I start with the basic ratio and then add more water or cornstarch deepening on the consistency that I’m getting.

Basic ratio

2 parts cornstarch to 1 Part water

Ingredients

• 2 Cups Cornstarch (AKA Cornflour)
• 1 Cup Water
• Food coloring (optional)

Instructions

What is the right consistency?

If you’ve never made oobleck before one of the hardest things to figure out is just what you are looking for in terms of texture and consistency. I use this as my guideline: When mixed you should be able to press a handful of oobleck into a ball in your hand; when you release the pressure the ball should “melt” back into a liquid.

Troubleshooting

• If your oobleck is too watery, add a couple tablespoons of cornstarch and mix.
• If you’re oobleck is too flaky or solid, add a couple tablespoons of water and mix.

Tips

• If you want to make several colors of oobleck make them in separate batches and then dribble the colored oobleck together.
• I do not recommend dropping different colors of food coloring directly on the oobleck as it will quickly mix into a purple mess.
• Oobleck tends to dry out quickly with a lot of play. If that happens simply refresh it by adding a little more water.
• To store oobleck let it dry out in a bin open to the air, then refresh it with water when ready to use again. I tried storing it in an airtight container and after few days it spoiled.

Clean-Up & Disposal

• How to clean up Oobleck: LET IT DRY! Once oobleck dries it returns to a cornstarch powder that can be easily swept or vacuumed up.
• Oobleck can be wiped off hands and clothes easily with a damp cloth.
• DO NOT WASH IT DOWN THE SINK! Oobleck can clog drains so do not our it down the drain. Wasing off dusty hands is okay but if kids have a lot of oobleck on their hands have them rinse it off with those outside.
• Dried oobleck can be placed in the trash or compost bin.

10 Awesome Oobleck Activities for Kids

1. Add Baskets & Sieves

Try using strawberry baskets and sieves! Place a handful of oobleck in a strawberry basket, collinear, or sieve and watch it drip through the bottom!

2. Paint with Oobleck

Make batches of oobleck in different colors then drizzle the colors together onto a large shallow tray. My daughter even made a heart with her oobleck.

3. Make an Oobleck Fountain

This was a hit at a recent event! This is the coolest impromptu activity for a group. Make a TON of oobleck, add in some baskets, colanders, buckets, splatter guards and sieves and build!

4. Mix Oobleck with Your Feet

This was a hit at Camp STEAM!

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5. Make Oobleck Glow

A fantastic sensory play experience that glows! See three different ways to make oobleck glow here:

6. Make Oobleck Dance

You read that right, make oobleck dance using sound waves!

7. Freeze it!

A fun sensory activity on a hot day.

8. Color Explorations with Oobleck

Turn oobleck into lesson on color mixing like this and this.

9. Walk on Oobleck

Perfect for events or parties!

10. Make It Erupt!

Add a little baking soda and turn it into a fizzing experiment!

If you enjoyed this be sure to check out Wizards’ Brew, another favorite in our house!

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