This is a close-up photo of the pockets in Styrofoam or polystyrene foam.
This is the chemical structure of polystyrene.
Common examples of polystyrene include foam packing material, bean bag pellets, and Styrofoam cups.
Acdx, Creative Commons License
Dissolving Styrofoam or another polystyrene product in acetone is a spectacular demonstration of the solubility of this plastic in an organic solvent, plus it illustrates just how much air is in the Styrofoam.
Dissolve Styrofoam in Acetone
All you need to do is to pour a bit of acetone into a bowl. Take styrofoam beads, packing peanuts, chunks of styrofoam, or even a styrofoam cup and add it to a small container of acetone. The styrofoam will dissolve in the acetone much like adding sugar to hot water. Since styrofoam is mostly air, you may be surprised by how much foam will dissolve in the acetone. A cup of acetone is enough to dissolve an entire bean bag worth of styrofoam beads!
How It Works
Styrofoam is made up of polystyrene
foam. When the polystyrene dissolves in the acetone, the air in the foam is released, causing it to look like you're dissolving this massive quantity of material into a small volume of liquid. You can see a less-dramatic version of the same effect by dissolving other polystyrene items in acetone. Common polystyrene products include disposable razors, plastic yogurt containers, plastic mailers and cd jewel cases. The plastic dissolves in just about any organic solvent, not just acetone. Acetone is found in some nail polish removers. If you can't find this product, you could dissolve styrofoam in gasoline just as easily. It's best to do this project outdoors since acetone, gasoline and other organic solvents tend be toxic when inhaled.