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Cornstarch Packing Peanuts

In this exploration, students add water to cornstarch packing peanuts and observe the surprising results!

Cornstarch and water do funny things when you mix them together. Bits of cornstarch become suspended in water - this means that they are being held in the water, but are not really dissolving or breaking up in the water. Because cornstarch bits are so tiny it looks like they are fully dissolving and 'disappearing' in the water.

These activities are part of Science World’s Big Science For Little Hands program. They were developed and tested with preschool and kindergarten educators. Some of the activities are done in stations.

Mysterious Mixtures PDF from Big Science For Little Hands.

Objectives

  • Observe a solid cornstarch packing peanut break apart in water.

  • Compare and describe cornstarch packing peanuts both before and after adding water.

Materials

  • Per Class:
    cups or tubs of lukewarm water
    cornstarch packing peanuts (a commercial variety, PlayMais®, is available for purchase at many toy stores. Moving companies may also sell them.)

Key Questions

  • How does the packing peanut feel when it is dry?
  • How does it feel when it gets wet?
  • Does it look different when it gets wet?
  • What do you think happened to it?

What To Do

  1. Dip the end of a cornstarch packing peanut in water. What happens?
  2. Stick the wet end to another packing peanut.
  3. Try building something by sticking packing peanuts together.
  4. Put a few packing peanuts in the water and stir. What happens?
  5. Leave the mixture for 15-20 minutes. What happens? (You may notice the cornstarch separating from the water and settling at the bottom.)

Extensions

  • For comparison, try dissolving a Styrofoam (polystyrene) packing peanut, as well. If you cannot find packing peanuts, you may tear up a Styrofoam plate or cup and use the pieces.
  • For another fun cornstarch activity, try making Oobleck!