Colorful Oobleck Fun
You’ve studied solids, and you’ve studied liquids. Aside from gases, you may think there are no other states of matter. But not so fast! Not only are there other states of matter, but there are also substances that don’t behave quite like any of the states we know!
What You Need
- Cornstarch (You should be able to find this in the kitchen)
- A Ziplock bag
- A spoon and/or chopstick
- Food Coloring
What to DoOpen up your ziplock baggy and add the ingredients in the following order:
- 2 spoonfuls of cornstarch
- 1 spoonful of water
- And a few drops of food coloring (that last part’s just to make it pretty - it doesn’t change the science!).
You can halve, double, triple, or even octuple this recipe to make as much goo as your heart desires (or your baggy will hold!).
Securely zip up your baggy, then squish around the contents until they start to mix together. Once everything is mixed up, open up the bag and take out your goo!
What's Going On?
Play around with your new blue, green, pink, or whatever-color goo. Once you've become acquainted with your goo, think about the following questions:
Is the goo a solid or a liquid? What happens when you put it down on a counter top? What about when you pick it up?
Not so simple, eh?! The goo we’ve made is what scientists like to call a non-Newtonian fluid. Basically, it’s a substance that acts like a liquid when you work gently with it, but acts like a solid when you are rough with it and apply a lot of force. Try stretching the goo apart slowly, and then ripping it apart quickly — what’s the difference?
Your goo acts this way because when it is at rest or being worked with gently, it is a flowing mixture of the cornstarch and water. When you’re aggressive with the goo, the cornstarch and water mixture packs together to behave more like a solid. Once you stop knocking it around, everything relaxes and it’s free to act like a liquid once again!
If there was a pool filled with this goo, could you swim in it? What about diving into the pool? You can test this by making a mini pool in big container and trying to run across it — but you’d better test this outside in the grass!
- Aliya Merali