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Ever since we made Oobleck as part of our Kid Wonder Box, my son has been asking to make it again because he had so much fun with it. Both my kids played with it for hours, pretending to be swamp monsters!

This video was from February when we got our Kid Wonder box. I can’t believe how much my son has grown since then! Also, this is my favorite video of him ever!

With Halloween just over a month away, this is a great time to do this activity with your kids. They can become swamp monsters, or you can color it like zombie blood, add fake eye balls…Or just keep it simple and play with it any way your child likes. 🙂

My daughter insisted on wearing her Tinkerbell costume while we played with the Oobleck, it’s one of the reasons we chose to color it green!

I love making Oobleck with my kids for several reasons:

  1. Kids love to play with it and get messy
  2. It is a unique and interesting non-Newtonian fluid (explained in the science section below)
  3. Easy and inexpensive to make yourself
  4. Easy to clean up
  5. Encourages kids to use their imaginations while playing with it
  6. Oobleck was named after the Dr. Seuss book, Bartholomew and the Oobleck, so you can incorporate reading into this activity

Let’s talk about the science behind Oobleck

Oobleck is a simple mixture of cornstarch and water that is a non-Newtonian fluid. Non-Newtonian fluids do not follow Newton’s law of viscosity, which states that fluids have a constant viscosity, independent of stress.

In non-Newtonian fluids the viscosity changes under force; in this case making the Oobleck more solid when force is applied, and more liquid when force is removed.

If you punch Oobleck it will harden. Once you stop the forward force from the punch, your fist will sink into the liquid. People have also done demonstrations walking on Oobleck like a solid walkway. When they stop walking they will sink into the liquid.

Source: Wikipedia – Non-Newtonian Fluid

Make your Own Oobleck

You and your kids will have a blast making and playing with Oobleck. Kids age 3+ should be able to help you make the Oobleck, and kids age 1+ will enjoy playing with it after you’ve mixed the ingredients together for them.


Oobleck is non-toxic, so it is taste safe if your little one sneaks a lick of it (it’s just water, cornstarch and food coloring). But avoid allowing your children to eat it – it won’t taste good!

The food coloring can stain anything it comes into contact with, so take that into consideration when deciding whether or not to add color (our hands all got stained green from the green food coloring when we played with it, but it washed off after a couple of washes).

Oobleck can be very messy to make and play with (*see note below). The good news is it cleans up easily with water. I suggest protecting your surfaces with a plastic covering or wax paper. The Oobleck won’t stick or get absorbed in plastic or wax covering, so your kids can play on these materials while keeping your table clean.

Oobleck would absorb into a cloth table covering, for example, so I wouldn’t recommend using something fabric based or absorbent to protect your table.

*Side note about the mess level of this experiment:

If you don’t like messes, this probably isn’t the best activity for you. If you asked me two years ago (or even one year ago) to do this experiment, I would have said NO WAY! I like to keep a neat and tidy house, and anything that makes messes was off limits. No play dough, no slime, no sand, especially no Oobleck!

Eventually I realized how much learning, experimenting, and fun we were missing out by not doing these “messy” activities, so I gave it a try… And you know what? IT IS MESSY!

Just poring the cornstarch into the measuring cup I managed to get the table, chair, floor, and my son (shirt, shorts and hair) all covered in corn starch! And the messy part of this experiment hadn’t even started yet. 😉

I DO still get nervous and frustrated as I see the mess grow. But then I see my kids playing and laughing and learning, and it makes the mess all ok.

This was our table at its messiest

Our clean up after the experiment today took less than 5 minutes. I’d say that mess was worth the short clean up time. 🙂

Materials Needed:

  • Bartholomew and the Oobleck by Dr. Seuss (optional)
  • 1 cup water
  • 1.5 to 2 cups Cornstarch
  • Food coloring (optional)
  • Bowl
  • Parchment paper/wax paper/plastic placemat/plastic tablecloth or other non-porous protection for your surface (optional)


  1. (Optional) Read Bartholomew and the Oobleck with your kids, you can find this book at your local library, bookstore, or Amazon

2. Add the water to the large bowl

3. Slowly add the cornstarch, mixing continuously as you add it (we used our hands to mix). Start with 1.5 cups, adding up to 2 cups to get the consistency right. Don’t worry, if you add too much corn starch just add some water. You want the Oobleck to retain fluid like properties, but be solid when a force is acting on it.

4. (Optional) Add 5 drops food coloring of your choice, and mix in well with the Oobleck

5. Experiment and play with the Oobleck! Listed below are some suggestions of ways to EXPERIMENT and PLAY with Oobleck:

5a. Liquid or solid? Ask your child if they think this is liquid or a solid and have them explain their choice.

5b. Once your child realizes it behaves as both liquid and solid, ask them to make it act like a liquid, then make it act like a solid.

Liquid and solid at once! It’s in a solid ball between his hands but also dripping like liquid from the back of his hands.

5c. Can you roll the Oobleck into a ball? What happens when you stop rolling it?

5d. If you made a large quantity of Oobleck, can you walk on it?

5e. Become a swamp monster! Have your child let green Oobleck ooze and fall between their fingers like a swamp monster

5f. Make a pool of Oobleck on the table and hit it hard with your hand, does it feel solid under your hand. Once you stop the downward force, your hand will sink into the liquid Oobleck.

5h. Move your fingers slow, then very quickly through the Oobleck. How does it react?

5g. Place the Oobleck in a bag and drop it onto the table. How does it react? Play around with it inside the bag.

What Happened:

Oobleck is quick and easy to make, and endlessly fun to play with. Because it’s a non-Newtonian fluid it behaves as a solid when a force (such as a strong finger to hand) is placed on it, but it behaves as a liquid when force is removed. It will drip between your fingers like liquid, but will also harden into a solid ball when continuously rolled in the palms of your hands.

The Oobleck in the bag hits the table with a loud “thump” because it is behaving as a solid when accelerated falling (due to the force of gravity) is stopped by the upward force from the solid table preventing the bag from penetrating it. After the bag hits the table and comes to rest, there are no longer any forces acting on it, the Oobleck returns to a liquid state.

I recommend borrowing Bartholomew and the Oobleck by Dr. Seuss from your local library or you can purchase it on Amazon with the link below.

Oobleck got it’s name from this book (although the Oobleck in the book is made with magic and not cornstarch and water…). Even though the story doesn’t go into the science of Oobleck, it does teach the value of saying “I’m sorry,” which is a lesson we can all benefit from reading. 🙂

The first time I read Bartholomew and the Oobleck I was disappointed…The Oobleck in the book isn’t the same as the Oobleck we make, even though Oobleck as we know it is named from this book.

They don’t talk about science in the book because the Oobleck is made by magicians using unusual and strange ingredients. But my kids liked the book, so we have re-read it several times now…

I’ve come to appreciate the fun and silly story (as always from Dr. Suess) and the lovable Bartholomew with his adorable name and honest nature. Most importantly, I like the themes of simplicity, appreciating what you have, and owning up to mistakes by saying “I’m sorry.”

Making Oobleck can be a fun science activity and reading opportunity for you and your kids anytime of the year! It is especially fun around Halloween, because the non-Newtonian nature of Oobleck lends itself easily to creepy themes. 😉

Have you made Oobleck with your kids yet? Will you be trying this soon? What do you think about the book, will you read it with your kids?


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