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.
Materials:
- An outdoor area or other space that is OK to get messy and easy to clean
- Clothes for getting messy in
- Household examples of solids such as:
- The table
- A toy block
- Your phone
- A baseball
- Household examples of liquids such as:
- Water
- Milk
-Juice
- Paint
- Corn starch (about 3 cups)
- Water Measuring cup
- Mixing bowl
- Mixing spoon
- Baking sheet or tray
- Optional: food coloring
- Optional: “Bartholomew and the Oobleck” by Dr. Seuss
Solids and liquids
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:
- Have a scavenger hunt for solids around the house. See if you can fill a laundry basket with examples.
- Show your child how juice changes its shape as it's poured into differently shaped glasses or vases.
- Quiz your child by naming a solid or liquid and having them tell you which one it is.
All of these ideas are optional, so long as your child has a basic understanding of what a solid and a liquid are.
Making oobleck
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:
- Stir slow and then fast.
- Grab a handful and quickly mold it into a ball (it will become solid), relax your grip and watch it “melt” back into the bowl (liquid).
- Throw one of your Oobleck balls against a wall, rock, or ground. Watch it hit as a solid then ooze back into liquid.
- And, my personal favorite, pour some Oobleck onto the baking sheet or tray and watch it flow around as a liquid. Then, suddenly, smack your hand down onto the tray. Your child (and any other observers) will jump and shield themselves, expecting to be splattered, but they won’t be! It will instantly turn solid under your hand. As you lift your hand up, it will turn back to liquid again. Let your child try it!
Teaching moments:
- Make a couple of batches of different colors and use them for color-mixing fun as well.
- Incorporate the science vocabulary words viscosity (how thick or flowing a liquid is) and force (a push or a pull on an object).
- Watch a video of someone walking on Oobleck. Yes, it’s possible! https://www.youtube.com/watch?v=q-DZ0f0_NCA
- Read the book “Bartholomew and the Oobleck” by Dr. Seuss