Cornstarch goop.

Some people call it ooblek. It was a year-round favorite in my classroom, and the perfect activity to throw together when I needed something extremely fun yet (relatively) easy to clean up. Perfect for a day that unexpectedly kept us cooped up inside. So, what is it? How do you make it? Why will you love it? Let’s go!

Simple Ingredients

You know I like things simple! And this is about as simple as it can get. Two ingredients. Equal amounts. Mix it up and play!

All you need for this amazing concoction is equal parts of cornstarch (aka corn flour outside the US) and water. Simple and safe, so you can let the kids help you mix it up. I like to use a pretty deep plastic tray for this, so they can dig in and really experience the awesomeness. Keep it shallow enough so you’re not using so much that it’s wasteful.

It’s science! It’s fun!

So what IS this stuff? If you haven’t made cornstarch goop yet, you are going to love it! Here’s the science behind it, but basically goop is like a solid and a liquid at the same time. Kids who like squishy, messy fun will be enthralled with this stuff for days. And you can use it for several days in a row! Let it dry out overnight (the cracked surface that results is so cool!) and then just add more water and use it again. *You’ll know from the funky smell after several days that it’s time to toss this stuff!

Variations!

Now, playing with this stuff as is with bare happy hands will keep the kids busy for a long time. Squeeze, poke, press, scrape, drizzle, repeat… But it’s fun to add tools and colors too! I like to wear out one variation before moving on to a new one, so the kids can really become experts. Provide even more science-based fun to the mix by adding two shades of food coloring, liquid water color, or tempera paint to the water or directly to the goop. Or add all kinds of tools like spoons, paste scrapers, sturdy plastic forks… Toss in plastic cars, blocks and people. Let your imagination and the kids’ ideas guide you. The possibilities for messy scientific fun are endless!