The Amazing Shrinking Peanuts

This general technique also may be used as an interesting demonstration.

• Acetone
• Foamed Polystyrene "Peanuts"
• Large Beaker

1. Place a small amount of acetone in the bottom of a large beaker.
2. Add handfuls of polystyrene "peanuts" quickly.
3. The acetone will collapse the foam (without truly dissolving it).

There are many interesting lead-ins and follow-up discussions - BE CREATIVE. One example would be a discussion of waste volume considerations (the collapsed foam certainly occupies much less space than the original foam!) Young students especially like to try to solve the problem of how to get a large box full of "peanuts" into a 600 mL beaker. The solution, of course, is to use about 40 mL of acetone.