Fun with Non-Newtonian Fluids: How to Make Oobleck
Welcome to the strange world of Non-Newtonian fluids! Let's make Oobleck, a substance that's not quite a liquid, not quite a solid, but a whole lot of fun! This is an easy DIY activity you can do with only 2 ingredients from your cupboard, and a great introduction into viscosity, pressure, and fluid dynamics!
Roll up your sleeves and get ready for some hands-on science!
So, what exactly is Oobleck? To understand, let's talk about the difference between Newtonian and non-Newtonian fluids.
Newtonian Fluids
Isaac Newton, when he wasn't busy inventing calculus, studied the properties of fluids. Specifically, he examined viscosity. Think about the difference between honey and water. Viscosity describes how easily a liquid flows. Newtonian fluids can only change their viscosity by changing their temperature. Imagine the difference between honey in the fridge vs. honey on a hot summer day.
Non-Newtonian Fluids
Oobleck is a non-Newtonian fluid. This means it's viscosity changes when you apply pressure! Push it, hit it, or roll it and it acts like a solid. Let it sit, and it melts into a liquid. This happens because the cornstarch particles in the oobleck are suspended in water. When you apply force, the particles temporarily lock together, making it act like a solid.
Let's make it!
- 1 cup of cornstarch
- 1/2 cup of water (you may need a little more)
- A mixing bowl
- Food coloring (optional, for a splash of color)
- A spoon (but your hands work best!)
Step 1: Mix it up!
Pour the cornstarch into the mixing bowl.
Cornstarch is our star ingredient, and it's what's going to turn ordinary water into something extraordinary!
Add water gradually to the cornstarch.
Start with 1/2 cup of water, pouring it slowly into the bowl. If you want to add some color, mix in a few drops of food coloring with the water before pouring.
Stir the mixture.
Use a spoon (or your hands) to mix the water and cornstarch together. As you mix, you'll notice the mixture thickening. If it’s too dry, add a little more water, a tablespoon at a time, until you get a consistency that's thick but not runny.
Test your oobleck.
To see if you've made it just right, try this: quickly press your fingers into the mixture. Does it feel solid? Now, gently lift your fingers out. Is it liquid? If yes, congratulations, you've just made Oobleck!
Step 2: Playtime with Oobleck!
Now that you've made your Oobleck, it's time to have some fun! Here are a few ways to explore its crazy properties:
Punch It, but don't break it!
Try quickly poking or punching the surface of your Oobleck. Notice how it feels solid under pressure. This is because Oobleck is a non-Newtonian fluid, meaning its viscosity (how thick or thin it is) changes depending on the force applied. When you hit it, the particles lock together, making it feel solid.
Let it flow through your fingers.
Scoop up some Oobleck in your hand and then open your fingers. Watch as it oozes and drips like a liquid. The moment you stop applying pressure, it returns to its fluid state.
Roll it into a ball (but not for long!)
Try rolling some Oobleck into a ball in your hands. Keep rolling, and it stays solid. But as soon as you stop, it melts back into a puddle. Oobleck behaves like a solid when under stress but relaxes back into a liquid when left alone.
Make Oobleck dance.
Place your Oobleck on a speaker covered with plastic wrap, and play some music with a strong bass. Watch as the vibrations make the Oobleck bounce and dance! The vibrations cause the Oobleck to momentarily act like a solid and then settle back into a liquid.
Step 3: Clean up and analyize your results
Cleaning oobleck.
Oobleck is easy to clean! If you spill any, let it dry, and then you can simply sweep it up. To dispose of oobleck, throw it in the bin, never pour it down the sink, as it can clog drains.
What you learned.
Think about how Oobleck's behavior is different from what you expect from regular liquids. What other non-Newtonian fluids can you think of? (Hint: Tomato sauce and toothpaste are a couple more!)
You’ve just explored concepts like viscosity, pressure, and fluid dynamics—all through the simple act of mixing cornstarch and water. Next time you see a liquid or a solid, you might wonder...could there be more to it?
So, the next time you’re looking for an engaging, hands-on science experiment, remember that sometimes the most amazing discoveries start with just a little cornstarch and water.
Happy experimenting!