If you have never made oobleck before, you are in for a treat. This is a craft/science experiment/mess that is an all-time favorite of so many children (and adults)! Be sure to make it outside or in another area that is easy to clean up. You’ve been warned.
First, you should introduce your child to the concept of solids and liquids. Fortunately, a home is filled with many examples of each.
For simplicity’s sake, choose solids that do not readily change their shape like squishy pillows or stuffed animals. You can make this introduction in whatever way you think will work best for your child. Explain that things (matter) that hold their shape are called solids. Show them some examples. Then, ask your child to find some examples. Explain that substances (matter) that flow and take the shape of whatever container they’re poured into are liquids. Similarly, show them some examples and then ask them to name some examples.
If you want to take this further, you might:
All of these ideas are optional, so long as your child has a basic understanding of what a solid and a liquid are.
Now, the fun part! Tell your child that you are going to make Oobleck, which is a substance that breaks the rules. It is sometimes a liquid and sometimes a solid and can change back and forth between the two!
The Science: This is a more scientific explanation of what you’re doing. Feel free to share whatever portions of this you feel will aid or enhance your child’s understanding. Oobleck is a non-Newtonian fluid, meaning its viscosity changes depending on how much force is applied to it. It is both a solid and a liquid. In chemistry, it is called a colloid—particles of one substance suspended in another substance without being chemically bonded together. Another example you know? Quicksand.
Mix about 2 cups of cornstarch with 1 cup of water. Stir slowly. Fine-tuning is always required. Add more water or cornstarch until you get the desired consistency. What is that? When the mixture is liquidy when stirred slowly but firms up when stirred quickly—you’re there.
Optional: If you’ve decided to add food coloring, now is the time.
Now, get messy and experiment! Let your child really dig their hands in (literally) and explore the texture and the amazing way Oobleck behaves. Here are some things to try: