How To Make Oobleck: Easy Science Experiment For Kids
Oobleck is an easy science experiment for kids that doubles as a mind-blowing sensory experience! This fun activity never fails to leave my 4– and 6-year-olds squealing with amazement as they scoop up a handful of goo and squeeze it tightly into a ball only to have it run through their fingers when they open their hand. Is it solid? Liquid? Just what is it and how do you make Oobleck at home?
What Is Oobleck?
Oobleck is an ooey-gooey substance that the whole family is going to want to scoop, pour, and dig their hands into! This cornstarch and water mixture gets its name from Dr Suess’ book, “Bartholomew and the Oobleck,” in which a boy must rescue his town from a sticky green goo called oobleck that rains down from the sky. You may want to get a copy to read and introduce the green goo before you share how to make oobleck with the kids! Don’t worry, our homemade oobleck recipe is actually much easier to clean up than the mess poor Bartholomew gets into and can simply be wiped away with water.
While oobleck is so much fun to play with on its own, it’s even more intriguing once you break down the science behind this mysterious concoction. We know that most matter (the “stuff” that everything around us is made of) can be categorized into three main states: solid, liquid, or gas. These categories are determined based on the observation of particles behaving a certain way. For example, a liquid flows freely, conforming to the shape of a container while a solid maintains a fixed volume and shape.
Oobleck, however, is a magical little mixture that blends the lines between solid and liquid. We know that a liquid flows but let’s talk about one of the properties of a liquid: viscosity, or how easily a liquid flows. If a liquid has a low viscosity, it means that it flows freely — like water being poured from a pitcher. On the other hand, a liquid with a high viscosity resists flow and behaves more like syrup. Sir Isaac Newton stated, at its most basic level, that the viscosity of a liquid remains constant based on temperature. Oobleck is one of only a few unique substances in which its viscosity changes based on the pressure or force it’s under, going against Newton’s Law of Viscosity and therefore making it a Non-Newtonian fluid. (Can you think of another Non-Newtonian fluid that you may be able to find in your kitchen? Ketchup!)
The cornstarch in oobleck does not dissolve in the water, rather its particles become suspended by the water molecules. For this reason, the substance is called a suspension. If oobleck sits undisturbed in its container for a period of time, you will notice that the cornstarch sinks to the bottom and the water will separate and rise to the top. This is especially important to note because after your experiment is complete, in order to avoid clogging your pipes, you will want to dispose of the oobleck by throwing it in a trash bag and not in the sink where it could separate in the pipes and clog your drain!
To summarize, oobleck will behave as both a solid and a liquid depending on how much force is exerted upon it. How cool!
Now you’re ready to mix up your own oobleck recipe at home.
How do you make Oobleck?
After taking in that scientific explanation, you may be wondering if you’re up to making this amazing Non-Newtonian fluid. But guess what? The best part about oobleck is how easy it is to make! This simple oobleck recipe can be made in under five minutes — and you might even already have everything you need in your pantry! This nontoxic and kid-friendly oobleck recipe is perfect for kids of all ages to enjoy as a fun science experiment at home. Here is how to make oobleck:
- 2 cups cornstarch
- 1 cup water
- Food coloring (optional)
Step 1: Add two cups of cornstarch to a medium-sized bowl. Give the kids an opportunity to touch the cornstarch. Ask them, “Is it smooth or rough? Light or heavy?”
Step 2: Slowly add one cup of water* to the cornstarch.
If you’d like to make colorful oobleck, it’s easiest to add your food coloring into the water before mixing it with the cornstarch.
Step 3: Stir the ingredients together in the bowl using a spoon, spatula, or even your hands! Ask your kiddos, “Is it easier to stir if you move the spoon slowly or quickly?”
Step 4: Keep the oobleck mixture in your mixing bowl or pour it onto a flat container like a baking sheet.
Step 5: Play!
Note: The consistency of the oobleck should be thick but still able to move. If it’s too runny, you can add a little more cornstarch. If it is crumbly, add more water.
In order to avoid clogging your pipes, you will want to dispose of the oobleck by throwing it in a trash bag and not in the sink where it could separate in the pipes and clog your drain!
Thought Starters for Kids
- Can you squeeze the oobleck into a ball? What happens when you open your hand?
- Slap the top of the oobleck. Does it splash? What happens if you gently rest your hand on the surface?
- Slowly scoop out a spoonful of oobleck. Does the hole stay open or refill itself?
- Would you call it a liquid or a solid? Why?
Oobleck will last for a few days if it’s stored in a tightly sealed container. If it appears dry, you may need to add a spoonful or so of water to return it to its optimal consistency.
This simple and quick oobleck recipe makes a tabletop batch, but if you’re feeling ambitious you can easily scale it at a 2:1 ratio to create as much as you want. Anyone up for an oobleck-filled swimming pool this summer? Learn more about craft and DIY ideas to enjoy with your kids.