# How to Make Oobleck! A Non-Newtonian Fluid

This simple 2 ingredient recipe how to make oobleck is a great way for kids to learn about the science of liquids through play at home or in the classroom. I love this oobleck activity for kids of all ages because at each level, they will be learning different STEM things. Oobleck is a lesson that just keeps kids learning.

Oh, and oobleck is cool!   If your kids have not yet explored “Non-Newtonian liquids”, then they should make Oobleck!

## What IS Oobleck?

I think the best place to start is to figure out exactly what is this strange oobleck substance. Oobleck got its name from the Dr. Seuss book, Batholomew and the Oobleck and is a non-toxic way to easily demonstrate what a non-Newtonian fluid id by using a suspension of starch.

Oobleck and other pressure-dependent substances (such as Silly Putty and quicksand) are not liquids such as water or oil. They are known as non-Newtonian fluids.

Scientific American

A non-Newtonian liquid demonstrates variable viscosity, which means that the viscosity (or “thickness” of the fluid) may change as force is applied or, less commonly, over time.

A Newtonian liquid such as water has a constant viscosity.

### Examples of non-Newtonian liquids

When you think of examples of non-Newtonian liquids, you think of ketchup, syrup and Oobleck.

• Ketchup becomes runnier, or less viscous, the more you shake it.
• Oobleck is just the opposite – the more you play with it, the harder (more viscous) it becomes!

Alright! Enough talking about oobleck, let’s make some and get hands-on experience with non-Newtonian liquids!

### Oobleck Ratio of Water to Starch

While there is not an exact amount of water or cornstarch ratio when making oobleck, the General guidelines for oobleck ratio is to try 1 cup of water for every 1-2 cups of cornstarch.

### Directions

#### (Optional) Step 1

If you are going to make colored oobleck, the best place to start is to add the food coloring to the water before you add the cornstarch. Make the water your desired color knowing that it will be lighter after adding the white starch.

#### Step 2

Combine the water and cornstarch together. You can start by measuring a 1:1 ratio of water to cornstarch and then adding additional cornstarch to see what happens…

You are looking for a consistency that cracks when you shove your stirrer through it quickly, but “melts” back into the cup.

## Oobleck Activities for Kids

One of the great things about making homemade oobleck is that the ways you can play with it are endless. You can try different things and then figure out why it works that way.

### Favorite Oobleck Experiments to Try

• Turn your cup of oobleck upside down quickly, what happens to it?  It should stay in the cup even if the cup is not upright until force is applied to the cup, breaking the colloid tension.
• Fill a strainer with Oobleck.   Watch how it slowly drizzles out.   If it stops dripping, what happens if you stir the goo?
• Pour a layer of goo into the bottom of a casserole dish. Slap the Oobleck mixture.  Does it act like water and splash?   Try to hit it harder. What happens?
• Can you take a spatula and lift a “slice” of oobleck off the plate? What happens?

#### Oobleck Cotton Balls for Hammering

Inspired by Time for Play, we decided to bake our cotton balls to harden the oobleck and create a smashing activity for the kids for the back porch or drive way!

We drizzled our oobleck over cotton balls and then baked them in the oven at 300 degrees until they dried out which took a little less than an hour.   We let them cool and then got out the hammer.

One of our boys loves hammering and his younger, not ready-for-nails brother joined him!

Yield: 1 batch

# Make Oobleck

Create this non-toxic non-Newtonian liquid with a simple oobleck ratio. Easy enough to do at home or in the classroom, kids of all ages are amazed by what this part liquid, part solid can do! Great for hours of play.

Active Time 5 minutes
Total Time 5 minutes
Difficulty easy
Estimated Cost \$5

## Materials

• cornstarch
• water
• (optional) food coloring

## Tools

• popsicle sticks
• toys to experiment with: strainers, colander, paper clips, cotton balls, spatulas...whatever you have on hand!

## Instructions

1. If you want colored oobleck, start by coloring the water first with the desired intensity of food dye.
2. Combine the water and cornstarch in a 1 cup to 1-2 cup ratio until you have a consistency that cracks when you shove a stir stick into it, but melts back when you remove it.

### More Oobleck Fun from Kids Activities Blog

How did your oobleck recipe turn out? What oobleck ratio did you end up with? Did you color your oobleck?