How to Make Oobleck That Acts Like a Solid and a Liquid

Learn to make oobleck, a fascinating non-Newtonian fluid that's solid when you hit it and liquid when you pour it.

1. What You'll Need. Gather these simple ingredients: 1 cup of cornstarch, 1/2 cup of water, food coloring (optional), a large mixing bowl, and a spoon for stirring. You might also want newspaper or a plastic tablecloth to protect your workspace, since oobleck can be messy. Having wet paper towels nearby for cleanup is always helpful too.
2. Making Your Oobleck. Start by pouring the cornstarch into your mixing bowl. Add a few drops of food coloring to the water if you want colored oobleck — this step is optional but makes it more fun. Slowly add about half the water to the cornstarch while stirring. Keep adding water bit by bit until the mixture has the consistency of thick honey. You'll know it's ready when it flows slowly off your spoon but feels solid when you poke it quickly. If it's too thick, add water one teaspoon at a time. If it's too thin, sprinkle in more cornstarch.
3. Testing the Science. Now for the fun part — experimenting with your oobleck's weird behavior. Try pouring it slowly from one hand to another and watch it flow like liquid. Then quickly punch the surface or grab a handful fast — it should feel solid. Roll it into a ball in your palms, then stop moving and watch it melt through your fingers. Try walking on a large batch slowly versus quickly, or see what happens when you stir it fast versus slow. Each experiment shows how this non-Newtonian fluid changes based on the stress you apply.
4. Understanding Why It Works. Oobleck is called a non-Newtonian fluid, which means it doesn't follow normal liquid rules. When you apply gentle pressure or move slowly, the cornstarch particles slide past each other easily, acting like a liquid. When you apply quick force or pressure, those same particles jam together and act like a solid. This happens because of the unique way cornstarch particles interact with water — they're suspended but not dissolved, creating this fascinating dual behavior.
5. Cleanup and Storage. Never pour oobleck down the drain — it can clog pipes. Instead, let it dry out completely and scrape the dried pieces into the trash, or add lots of water to thin it out first, then dispose of it outside. Clean up spills with warm water while they're still wet. You can store leftover oobleck in a sealed container in the refrigerator for a few days, but you may need to add a little water to restore the right consistency when you use it again.