Disolving solids

Different dissolving

With this experiment you can wow your friends as polystyrene appears to disappear!

Ingredients and equipment that you will need

Acetone (this is the main ingredient in nail varnish remover, but most of them are now diluted with water (they call it aqua on the bottle). If you can’t find an undiluted one, ask you mum to buy a small bottle of acetone at the chemist.)
A polystyrene cup or plate, or a piece of polystyrene foam used for packing.
A plate

Method and further information

Be careful with acetone because it is flammable and will damage polished surfaces. Put a polystyrene cup, plate or piece of expanded polystyrene packaging material onto a plate and pour on a few drops of acetone. If you leave the nail varnish remover to evaporate (well away from any flames) the polystyrene will crystallise out and you can set it in a mould. It seems quite different to the original, because expanded polystyrene is puffed up with air, whereas crystalline polystyrene is much more dense.

Be careful – you should ask an adult to help you with these experiments. Do your experiments in old yoghurt pots, jam jars or bottle tops. Don’t use cups or glasses in case someone thinks it’s a drink.