How to Make Oobleck: Cornstarch and Water Science Experiment

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Making oobleck is a fun sensory activity and science project for kids. With only cornstarch and water, you can make this non-Newtonian fluid that acts like a solid and a liquid at the same time.

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If your kids like slime, they will love oobleck (or as some likes to call it, homemade goop). As a parent, you will love oobleck too because it’s fun to play with like slime, but so much easier to clean up. Plus, you only need 2 ingredients! Sounds awesome? Read on to learn how to make oobleck.

One of the best things about this oobleck recipe is that unlike other science experiments, you can’t mess up. If your oobleck is too watery, just add more cornstarch. On the other hand, if your oobleck is too hard, simply add more water. 

The oobleck is edible, though I wouldn’t recommend trying to taste it. But that’s why oobleck is a great sensory activity for babies and toddlers because you don’t have to worry if some got into their little mouths by accident. 

That said, even preschoolers, kindergarteners, and elementary school kids will love touching and playing with oobleck! I will admit, even I think it’s a bunch of fun. If you want, you can add some food coloring to it and make it colorful. We left ours without color because my kids couldn’t wait to get their hands in it!

How to Make Oobleck

Ingredients:

  • 2 cups cornstarch
  • 1 cup water
  • (Optional) food coloring

Step-by-Step Instructions to Make Oobleck:

1. Add 2 cups cornstarch and 1 cup water to a mixing bowl or container. If you want to make more goop for multiple kids, you can simply increase the amount of the two ingredients. However, make sure that you always maintain the same cornstarch to water ratio.

2. Mix thoroughly until the cornstarch and water until your oobleck is formed.

3. (Optional) For a colorful oobleck, add a few drops of food coloring to the water, then mix with the cornstarch.

How do you know when you have successfully made the oobleck? You should be able to pick up the oobleck with your hand and squeeze it into a ball. When you let go, the oobleck ball should turn back into a liquid and drip off your palm.

How to Make Oobleck Recipe Balls
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Tips for Making the Oobleck:

  • If your oobleck is too watery, add a little bit of cornstarch and mix. Repeat until you get the desired consistency.
  • If your oobleck is too solid, add a little bit of water and mix. Continue until you reach the desired consistency.
  • As your kid plays with the oobleck, it will start to dry out. Simply add a little bit of water and mix and continue playing!
  • If you want to make several colors of oobleck, divide your oobleck batch into a few smaller bowls and add the desired food coloring. You can then put the different colors of oobleck next to each other and see how they interact!
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How to Play with Oobleck

There are so many possibilities when it comes to playing with oobleck. Here are some activity suggestions:

  • Just use your hands! Try and pick up as much oobleck as possible and make it into a ball by putting pressure on it with your fingers and palms. Then just relax your hands and watch it “melt”!
  • Take a measuring spoon or cup and scoop up the oobleck. Is it easy to scoop? Try hitting the oobleck with the back of the spoon. Does the spoon cause it to spread and ripple like water (liquid), or does the spoon bounce off like it just hit the floor (solid)?
  • Add small objects to the oobleck. Do the objects stay on top of the oobleck or do they sink like they are in quicksand? My kids had a lot of fun with this one in the dinosaur dig activity where they tried to rescue the little dinosaur figurines from the “mud” oobleck.
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The Science Behind the DIY Goop: What is Oobleck?

Oobleck is a special kind of fluid. A fluid is something that can move around easily and change shapes (like water). What makes oobleck special? It acts like a liquid AND a solid. 

Everything is made of particles. The way the particles behave decides if something is a solid or a liquid. Most things do not get to be both. But oobleck does!

Water, milk, and soda are liquids. They move around and take the shape of whatever container they are in. Oobleck acts like a liquid when it is handled gently or in a container. You see this when you dip your fingers slowly into the oobleck. The fluid is relaxed and acts like water. 

Think about how you cannot pick up your bathwater. It is hard to pick up the oobleck too! The particles that make up the oobleck move apart easily. This allows it to act as a liquid.

A solid is something that is hard, like a wall or your chair. You can’t push your hand in a solid wall. Oobleck acts like a solid when it is hit or pushed hard. When you thump or slap the oobleck, it feels like you have hit a soft wall. Your hand does not go through it as it did before! 

Think about how your muscles feel when you are scared. When you jump, your muscles get tight and hard. You can think about oobleck kind of like that. The particles squish together tightly. This allows it to act like a solid.

Ever imagined (or feared) being stuck in quicksand? Quicksand is another example of this special kind of fluid! Using what you know now, do you know how you would escape? If you want to know more about this fun fluid, check out this article on non-Newtonian fluid.

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How to Clean Up and Dispose of Oobleck

Since oobleck is just water and cornstarch, cleaning it up is easy! There are a couple of options:

  • Rinse or wipe your hands, the bowl, clothes, or the table with warm water. Just make sure that you don’t pour too much of it down your drain because the cornstarch will clog the pipes. 
  • Leave the oobleck to dry. Once it’s completely dry, it will turn into a powder (cornstarch) and you can easily vacuum it up or toss it in the garbage.

How to Store Oobleck

Oobleck spoils easily. Even refrigerating it in an airtight container won’t help it last longer. For safety reasons, play with the oobleck as much as you want and throw it out right after. Good thing it’s so easy and inexpensive to make!

Final Thoughts on Making the Oobleck

Oobleck is a wonderful sensory experience for kids of all ages. As your kids play with oobleck, as them how the oobleck feels on their hands. Bumpy? Smooth? Cold? Warm?

And make sure you check out Bartholomew and the Oobleck, a book by Dr. Seuss. Oobleck got its name from the sticky, green gobs in the book! Thanks, Dr. Seuss!


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