|MadSci Network: Chemistry|
The process is called "dissolving". Different solvents dissolve different plastics or polymers; some plastics and polymers are insoluble in any solvent. If what you are using is really "styrofoam", it is made of polystyrene. There are several other types of polymer sometimes used to make similar looking insulating foam. Polystyrene does not dissolve in acetone. It does dissolve in heavier ketones like ethyl methyl ketone or isobutyl methyl ketone. It also dissolves in aromatic solvents like toluene or xylene. All of these substances I have mentioned are very bad smelling and very poisonous, and not at all suitable for an open display -- in fact, they should only be used in a fume hood. I can also think of many other things that will dissolve polystyrene, but none that are not rather obscure and very nasty. There is an insulating foam often used in packing for mailing books and the like, that looks and feels a bit like styrofoam (softer and spongier), and it will dissolve in water -- by far the best thing to be using in your experiments.
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