Kids, have you ever seen the packaging peanuts that are made of foam? Have you ever noticed two different kinds of these peanuts? One kind is bright white and sort of S-shaped, while the others are not so white and not so curved. In this experiment we will find out the differences between the two types.

The old-fashioned white kind of peanuts are made of Styrofoam, which is an expanded version of a polymer called polystyrene. The newer kind is called Ecofoam and it is made from corn starch. The most obvious difference between them in terms of chemical properties is that Ecofoam will dissolve in water while Styrofoam will not. Just put a foam peanut in a cup of water and wait a few minutes. The warmer the water the faster the Ecofoam will dissolve. Can you think of a way to take advantage of this difference for a useful purpose? Of course the answer is fairly obvious. Ecofoam was deliberately made as an alternative to Styrofoam because it will quickly degrade in the environment. It is therefore a more ecologically- and environmentally-friendly packaging peanut. (Can you see that Ecofoam would not make a very good beverage container, however?)

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

If you have an adult partner that has access to acetone (the active ingredient in many nail polish removers), they can show you that Styrofoam will "melt" in acetone while Ecofoam will not. This could therefore be one way to reduce the space that Styrofoam products take up as waste.

{SAFETY NOTE: Please leave the handling of any acetone only to an adult].

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Kathleen Carrado Gregar, PhD, Argonne National Labs 
[email protected]
June 1995

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Reference: Steven D. Gammon, J. Chem. Ed. 1994, 71, 1077.