An amazing sensory play and science activity is just minutes away and all you need is two simple ingredients, cornstarch and water, to create a rainbow of color! Explore polymers and non-Newtonian fluids at home or in the classroom. You need to learn how to make oobleck with cornstarch with the kids this year! Easy and cheap for a VERY touch-friendly and simple science activity!


How to make oobleck with cornstarch and water for simple science activities and sensory play ideas.Pin


Get ready to add this simple science activity, making colorful rainbow Oobleck to your science or STEM lesson plans this season. If you want to learn more about non-Newtonian fluids and create a cool tactile experience for your kids, let’s dig in! While you’re at it, make sure to check out these other fun simple science activities.

Our science activities and experiments are designed with you, the parent or teacher, in mind! Easy to set up, quick to do, most activities will take only 15 to 30 minutes to complete (longer if you want) and are heaps of fun! Plus, our supplies lists usually contain only free or cheap materials you can source from home!


Let’s get right to making oobleck or goo as its sometimes called… Oobleck with cornstarch and water is a classic science activity every kid needs to try. Head to the kitchen, open the cupboards or pantry, and be prepared to get a little messy. Your hands are the best mixing tools!

This rainbow-colored oobleck experiment explores the question:  What are the properties of a non-Newtonian Fluid?


Free Printable Rainbow Activities Guide and STEM Cards

Download this free mini Rainbow pack to get started today!



  • 2 Cups of Cornstarch
  • 1 Cup Water
  • Food Coloring
  • Tray, Bowl, and Spoon
  • Measuring Cups


Oobleck is a combination of cornstarch and water. You will want to keep additional cornstarch on hand if you need to thicken the mixture. Generally, the oobleck recipe is a ratio of 2:1, so one cup of water and two cups of cornstarch.

Since this rainbow oobleck activity calls for quite a few colors, you can go ahead and make smaller batches too!

STEP 1:  In your bowl or baking dish, add the cornstarch. You can start mixing the oobleck in a bowl and then transfer it to a baking dish if you prefer.

STEP 2:  If you want to give your oobleck a color such as green, add food coloring to your water first. Remember that you have a whole lot of white cornstarch so you will need a good amount of food coloring if you want a more vibrant color.


 STEP 3:  You can start mixing up your oobleck with a spoon, but I guarantee you are going to need to get your hands in there at some point during the mixing process.

Repeat the oobleck making process for each new color!


STEP 4: Transfer each color to a tray so you can mix and swirl it!



There is a gray area for the right oobleck consistency. First, you don’t want it to be very crumbly, but you also don’t want it to be very soupy. If you have a reluctant kiddo, hand them a spoon to start! Let them warm up to the idea of this squishy substance. Never force them to touch it, though.

The perfect oobleck consistency is picking up a clump in your hand, forming it into a ball of sorts, and then watching it flow like a liquid back into the pan or bowl.

Once you have your oobleck mixed to the desired consistency, add your desired accessories and play!


This oobleck activity can get pretty messy so be prepared with appropriate clothing and cover tables if necessary.

Can you make oobleck with baking soda or flour? This would be a great way to experiment with different materials, compare, and draw conclusions!


Oobleck is a fun substance to play with, which is made from cornstarch and water. It’s a bit messy too!

It is an excellent example of a mixture! A mixture is a material made up of two or more substances combined to form a new material that can be separated again. Could the oobleck mixture be separated into cornflour and water again? How?

Try leaving a tray of oobleck out for a few days. What happens to the oobleck? Where do you think the water has gone?

 This oobleck activity is also a great way to explore the properties of liquids and solids, known as the states of matter. Here, we combine a liquid and a solid, but the mixture doesn’t become one or the other. A solid has its shape, whereas a liquid will take the shape of its container. Oobleck is a bit of both!

That’s why oobleck is called a non-Newtonian fluid. This means it is neither a liquid nor a solid but has properties of both! You can pick up a clump of the substance like a solid and then watch it ooze back into the bowl like a liquid. Touch the surface lightly and it will feel firm and solid. If you apply more pressure,  your fingers will sink into it like a liquid.

Is oobleck a solid?


Or is oobleck a liquid?


Did you know that cornstarch is a polymer? Polymers have long chains that make them up (like the glue used in slime). When these chains get all tangled up with one another, they create more of a solid!


Want to experiment with viscosity? Easy, change the ratio of water to cornstarch! Viscosity is the physical property of fluids and how thick or thin they are, and how they flow.

  • What happens when you add more cornstarch? Does the oobleck become thicker or thinner?
  • What happens when you add more water? Does it flow faster or slower?

Can you make oobleck without cornstarch?

You could try making oobleck with flour, powder, or baking soda and compare the similarities and differences.

We tried an oobleck experiment of our own using just cornstarch and glue. Find out what happened —> OOBLECK SLIME


Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

  • 90+ classic science activities with journal pages, supply lists, set up and process, and science information. NEW! Activity-specific observation pages!

  • Best science practices posters and our original science method process folders for extra alternatives!

  • Be a Collector activities pack introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?

  • Know the Words Science vocabulary pack includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!

  • My science journal writing prompts explore what it means to be a scientist!!

  • Bonus STEAM Project Pack: Art meets science with doable projects!

  • Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics



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  6. Rainbow ooblek was a massive hit in our house. 2, 5 nd 7 year old absolutely loved it, spent ages playing. Thank you!

  7. Hello! I am a special education teacher putting together multi sensory science activities that my students can do at home with their families. Would you mind if I adapted this activity and used your photos and video if your name is credited? I would not be selling the materials or using them for commercial gain of any kind; just sending them privately to my students and their families. Thanks so much.

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