Science ideas for young children Part 9 – Oobleck

Teach young children about science by making a mess! Oobleck is a substance that acts both like a liquid and a solid.

This is the ninth article in a series of articles on science activities about science and the natural world that anyone can conduct with children. This can be done within a family, in a daycare setting, as part of school activities, a 4-H Club or with any group working with young children.

One of the earliest principles that young children learn are the states of matter. Whether something is a solid, liquid or gas can be easy to identify in the world and start children on the process of observing physical properties of matter. You can start this exercise by asking the student about what are the differences between a solid, liquid, and gas.

Here are some examples:

Solid

Liquid

Gas

  • Holds its shape
  • May turn to a liquid if enough heat is present (melting)
  • Cannot be compressed
  • Takes the form of the container it is in
  • May turn to a gas if enough heat is present (evaporation)
  • May turn to a solid if it gets cold enough (freezing)
  • Cannot be compressed
  • Takes the form of the container it is in
  • May turn to a liquid if it gets cold enough (condensation)
  • Can be compressed to fit in a smaller space

There is a substance that exhibits the properties of both a solid and liquid called oobleck. The formal name for this is a non-Newtonian fluid. Another example is Silly Putty. Oobleck gets its name from the Dr. Seuss book Batholemew and the Oobleck.

The recipe for oobleck is:

1.5 cups cornstarch

1 cup water

Food coloring (optional)

Mix the water and cornstarch in a bowl. You may try it with a spoon, but I found you need to use your hands.

Here are some things to try with the oobleck: WARNING! This is messy! Washing it down the drain might clog your pipes. This might be a good activity to do outside on a nice day and hose off afterward.

  1. Punch it! Does your fist go in? Why or why not?
  2. Pour it slowly from one bowl to another. How can it pour when it seems solid? Does the speed at which you pour make a difference?
  3. Try cutting it with a butter knife. Try stabbing it quickly or slowly slicing it. Does it make a difference?
  4. Take a fistful of the oobleck and hold it as tight as you can in your hand. What happens? What happens when you aren’t squeezing it tightly?
  5. Put some in a rimmed cookie sheet on a subwoofer speaker. Turn on the speaker and watch it “dance.” You can add food coloring while doing this for a neat effect. What makes the oobleck “dance?”
  6. Take action figures or dolls with hard feet and have the kids “jump” the figures across the bowl quickly and forcefully. Then have them set the action figures on top. This can be fun to act out. “Oh no! I am sinking in quicksand!” What happens and why?
  7. Take a small board that will float on water. Try hammering a nail into the board on both the water and the oobleck.
  8. If you are really ambitious, and have a lot of cornstarch, you can mix the material in a kiddy pool and try “walking on water.” This might be good for a larger event like a county fair. You can watch a video of this experiment being done at Michigan Tech.

Oobleck is a mixture of a solid (corn starch) suspended in a liquid (water). Oobleck behaves like a solid when force is acted on it quickly. This is because the pressure forces all the particles of corn starch together and they behave like a solid. When you move through it slowly, the particles of corn starch have time to move away and “slip” around the object. It can be helpful to explain it to children like sand at the beach. If you punch the sand, it doesn’t move, but you can wiggle a finger into the sand fairly easily.

See what other experiments you can try with the oobleck and enjoy your messy science!

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