One 1 dm
One 5 dm
The quantities given are for one demonstration
Up to 10 dm
of expanded polystyrene packing beads of the type in which glassware
is often packed for delivery. A disposable expanded polystyrene
coffee cup is also useful.
of propanone (acetone).
Pour about 50 cm
of propanone into a 1 dm
Fill the 5 dm
beaker with expanded polystyrene packing beads. Add the beads a
handful at a time to the propanone. They will shrink and fizz, eventually
forming a layer of sticky gel below the propanone.
If the 1 dm
beaker is filled with beads, the level will gradually drop as the
bottom layer dissolves. The beaker can be refilled at intervals.
Over 5 dm
of beads will dissolve although this may depend on the type of beads
Afterwards the beaker can be passed around the class; but take care
as the contents could be difficult to clean off clothes if spilled.
The empty 5 dm
beaker gives a striking reminder of the volume of beads that has