Cornstarch Packing Peanuts

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!