playing with blue oobleck

Oobleck recipe

Oobleck is simply a mixture of cornstarch and water… But it’s so much fun for toddler science! You can pour it like a liquid, but, if you squeeze it or hit it hard, it turns into a solid! How cool is that?! Your little ones will have a ton of fun exploring this super simple science experiment, including your preschoolers!

If you want to make your own Oobleck, you can jump right to the recipe and step-by-step instructions below! And, check out the bottom of this post for free Oobleck recipe cards! They make a great gift for children and students once they’ve made this recipe.

how to make oobleck with corn starch

What is Oobleck?

This is an excellent activity for young scientists – Especially those who love messy experiments! Learn why we think science for kids is so important in this post.

Sometimes also called ‘corn starch mud’ (but honestly, that’s half as fun to say…), this simple Oobleck recipe is great as a combination of messy play and science!

Basically, Oobleck is a Non-Newtonian fluid. Meaning that it doesn’t quite behave like it should. It’s not really solid (because it can be poured) but it’s not really a liquid because if you use enough force when you touch it, it’s hard and inflexible!

What is a Non-Newtonian fluid?

That’s the coolest part about Non-Newtonian fluids – With the exact same substance, you can let it pour through your fingers but it can also be as hard as rock! In upper elementary, I use this as an experiment to wrap up a unit on matter. What’s happening inside the mixture is pretty cool.

When you move the mixture very slowly (and with little force), the particles inside have time to move and adjust to the new shape. Much like water particles do when you pour them into a container – The substance takes the shape of the container. But, when you move the mixture quickly (by stirring fast or applying lots of force), the particles do not have time to move, making it feel and act like a solid!

Science Max even proved that you could jump/run on this Oobleck with enough cornstarch and water!

supplies for oobleck (cornstarch, water, and food coloring)

Making Oobleck: What you’ll need

I’ll warn you now – This experiment will get messy! You may want to wear old clothes or throw a cloth down wherever you’re making it. But, don’t worry – Since it’s just two ingredients (cornstarch and water) it’s pretty easy to clean.

Here is everything you will need to make your own Oobleck at home:


  • 1.5 cups cornstarch
  • 1 cup of room-temperature water
  • Food coloring (optional)

*I’ve heard rumors that you can substitute cornstarch with corn flour or baking soda. In all my years, though, I’ve stuck to cornstarch! If you try one of the alternatives, I’d love to hear how it goes!


  • A bowl
  • A spoon to mix with
  • Rags & Cleaner for after the experiment
adding food coloring to water
We found it a lot easier to mix the color in the water (rather than adding color to Oobleck)
pouring blue colored water into cornstarch
Add the water slowly!

blue oobleck mixture in bowl
This is the consistency you’re going for.

How to make Oobleck


  1. Put the cornstarch into a bowl.
  2. Add food coloring to the water (if desired). You only need a little bit!
  3. Slowly add the water to the cornstarch. Start with half a cup of water and add more as needed until the cornstarch is completely dissolved.
    • The trick when making Oobleck is to get the right consistency. If it is too runny, add more cornstarch! Too hard? Add more water.
  4. Have fun playing!

Kids love playing with this mixture. There are so many opportunities for sensory play with this easy Oobleck recipe! They can play with it in the container that it was mixed in, or pour the Oobleck ingredients onto a flat surface and explore it there!

If you’d like ideas about extending learning for this, jump to “extended learning” below!

Oobleck science experiment observation sheets

Use this free printable observation sheet if you want a worksheet to go with this activity. You can download it directly from the PDF below or head to my TPT store to download the worksheet and recipe cards in one download.

You can also download my Scientific Method worksheet for free from my TpT store if you’d prefer that one. By practicing this, they will become confident in their ability to hypothesize, test, and evaluate experiments!

Can I make Oobleck ahead of time?

If you’d like, you can make a batch of oobleck ahead of time and store it in a sealed airtight container and it will last for several days. I’ve always used a plastic container, but I’m pretty positive you could use glass, too.

How do I clean Oobleck?

Cleaning up is actually pretty easy! Because cornstarch is biodegradable, I break everything up with a spoon and toss it into the compost. There will probably be some residue left on your containers, counters, and whatever else your little one touched… But, wipe it up/rinse everything with some hot water and you’re set! You’ll just have to do one more pass with a sanitizer and everything is good to go.

Also, speaking from experience (whoops…), it’s easy to get out of carpets too once the mixture is dried. Not ideal, but easy to vacuum.

oobleck recipe 1 1
We discovered that if you apply enough force, then Oobleck acts like a solid
blue oobleck acting like a liquid (running through hands)
But, once you stop moving, it runs through your hands like liquid!

What if my kiddo eats some of it?!

Well, it’s probably not going to taste good. Sometimes, science experiments can look like recipes… And recipes are usually fun to taste test, so it’s totally understandable if curious kiddos give their Oobleck a taste! Thankfully, cornstarch is non-toxic, so don’t worry.

Extended learning

If you’re looking for ideas beyond just open-ended sensory play with this easy recipe, here are some ideas:

Pair the activity with Dr. Seuss’ book, Bartholomew and the Oobleck

I love to pair a fun activity with a good book. Read the book with your kids first, then ask them if they think they could make Oobleck, too? This way, children are already excited to make it!

Ask guiding questions

Another thing you can do is encourage exploration by asking guiding questions. Here are some ideas:

  • What happens if you slowly dip your finger into the Oobleck?
  • What if you stir it very quickly?
  • Is Oobleck a liquid? How?
  • Is Oobleck a solid? How?
  • Can you make it into a ball?
    • Hint: Get them to try making Oobleck into a ball. Then, place it onto a flat surface and let it sit – What happens?
  • Can you pour Oobleck?
  • Can you drive toy cars across Oobleck?

Overall, the idea is to encourage them to explore the mixture in a fun way. By emphasizing play, they can get a hands-on learning experience as they mix, hit, pour, and explore the weird consistency that Oobleck is.

Take-home recipe cards to make it again

These make a super cute little gift! Simply cut them out along the dotted lines, and you’re ready to make more Oobleck! You may want to laminate these recipe cards, though, since the experiment can get so messy…

playing with blue oobleck


Looking for a fun science experiment to do with your preschooler? Look no further than the infamous Non-Newtonian fluid – Oobleck! This simple recipe is a great way to introduce your child to the world of science. Plus, it’s super easy to make and clean up afterward… Although it may not look like it during the experiment! This can get messy – But it’s totally worth it, because kids love this fun activity.

Add some food coloring for extra fun, or, if you’re feeling super creative, you could add food coloring and some charms or other materials. I’m thinking festive-themed Oobleck – Like spiders, eyes, and mini pumpkin charms for Halloween!

More science posts

Searching for more science experiments and science-related activities to do with your little ones? Check out this category to see all of our posts about science for kids!


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