STEM Slime Activity: Explore Physics with This Oobleck Recipe

If they have fun while they're doing it, does it even count? Make a hypothesis and test it with this STEM slime activity. 

Enjoy messy science with one our favorite activities at the Orlando Science Center! Oobleck is a non-Newtonian fluid, meaning it can act like a solid or a liquid depending on what you do to it. With this STEM slime activity, you can learn about the states of matter and viscosity, practice lab skills like measuring and mixing, and have some ooey-gooey fun!


Be sure to explore the science behind oobleck toward the bottom of this page and try our other slime recipe so you can compare it to your oobleck! 


Recommended age range: Any age; younger scientists may need help measuring but will have fun mixing and playing. Older scientists can explore oobleck’s properties and the topics of polymers and viscosity.


Warning: This activity is messy! Mess-friendly play clothes are recommended for this activity! You may also want to set out newspaper or other materials to protect your surfaces, or work in an area you don’t mind getting messy. However, once oobleck dries, it can easily be cleaned up!


  • ½ cup cornstarch

  • ¼ cup water

  • Optional: Washable paint or food coloring 

  • Optional: Scent (for example, orange scented oil or peppermint extract)

  • Mixing bowl

  • Craft stick or other stirring utensil

Photo of materials for STEM slime activity


Step 1

Measure ½ cup cornstarch and add it to your mixing bowl.

Add cornstarch to mixing bowl

Step 2

Next, measure ¼ cup water and add it to your mixing bowl.

Add water to mixing bowl

Step 3 (optional)

Add a few drops of color or scent to your mixture.

Add coloring or scent to mixing bowl

Step 4

Stir until your mixture looks like glue... That’s it! You’ve made oobleck!

Stir STEM slime activity ingredients together

Step 5

Try some of the ideas below to expand on this activity and learn about oobleck's properties.

Experiment with oobleck STEM slime activity

Step 6

Throw your oobleck in the trash when you are finished. It will mold overnight and clogs drains!

Always dispose of oobleck in the trash can


Once you’ve made your oobleck, it’s time to do some experiments! Before you perform you start this STEM slime activity, make some predictions. Is the oobleck a solid, a liquid, or a gas? What will happen if you poke it? What will happen if you let it sit in your hand?


  • Poking the oobleck with your craft stick. How does it feel?
  • Gently stepping your craft stick on top of the oobleck. What happens?
  • Holding the oobleck in your hand. What happens when you squeeze it? What happens when you let go?

Expand on the Activity:

  • What happens if you pour oobleck through a container with holes in it, like a colander or a strainer?

  • What happens if you put plastic or LEGO figures in the oobleck? What stories can you tell? Use your imagination!

  • Use highlighter water to make oobleck that glows under a blacklight!

  • Make more! This recipe gives you a small amount of oobleck, but as long as you add twice as much cornstarch as water, you’ll have oobleck!

The Science Behind this STEM Slime Activity: Why Does Oobleck Act Like This?

  • Oobleck is made up of molecules called polymers, which are arranged in long chains. A great example of a polymer is a rubber band. The molecules can be stretched out or bundled up and stuck together like wet spaghetti.
  • When you put pressure on the oobleck, the molecule chains bundle up and stick together, making the oobleck act like a solid.
  • When there is no force on the oobleck, the polymers stretch out, and the oobleck acts like a liquid.
  • Since oobleck can be a solid or a liquid depending on whether you apply force to it, it is called a non-Newtonian fluid.

Learn More: Physics

  • In a solid, the molecules are tightly packed and vibrate in place. In a liquid, the molecules slip past each other, allowing liquids to flow. But have you ever noticed some liquids flow faster than others? Think about water versus honey. What makes them flow differently?
  • You can find out by rubbing your hands together quickly. What do you feel? That heat is from friction, or force that holds back the movement of a sliding object. As the molecules in a liquid slide past each other, they generate friction, too. The more friction they generate, the slower they move. Why is that? The force of the friction is holding back their movement, effectively slowing them down.
  • The friction between molecules in a liquid is called viscosity. The more viscous a liquid, the more energy it takes for it to flow. High visocity liquids, like honey or corn syrup, also tend to be thicker.
  • So what about oobleck? Oobleck is called a non-Newtonian fluid because it breaks the rules of Newtonian viscosity. On Earth, they’ll always be subject to the laws of gravity and the laws of motion Newton described. But the viscosity of oobleck, or the interactions and friction between the molecules, changes based on force you apply to applied to it.

Did you make your own oobleck and perform any experiments with it? We’d love to see how it turned out! Snap a photo of you making, testing, or playing with your oobleck and submit it to our Science Showcase here or tag Orlando Science Center and use #OSCatHome on social media! You might be featured on our channels. 

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