If you are REALLY keen to explore this-- make your own silly putty. If you vary the amount of catalyst, you can get a variety of cross-linking/doping in the resultant material, which produces varying macroscopic properties.
It's one of the clearest demonstrations of intuitive stat mech that I know of, in fact.
DD always found it just slightly off-putting that this kind of thing turns BOTH of her parents into giddy and slightly scary geeky people who are willing to try just about anything to 'see what happens' by the way.
