Hang on, isn't that a mistake? Plasticine is supposed to be plastic. If it is elastic, shouldn't it be called 'elasticine'? No, it shouldn't.

"Star-lite", star-like material is an example of elastic plasticine: if we shape it slowly, it seems to be very plastic, it can be lengthened almost ad infinitum, and even seems to 'float' under the influence of a minimal force. But if we shape it into a ball, it is very elastic, and bounces with a minimal loss of energy, similarly to a caoutchouc ball.

This silicon polymer invented in the middle of XX c. is an example proving that the usual division of materials into elastic, plastic and brittle is artificial, especially so in the age of modern technology. Even the division into liquids and solids isn't so clear-cut. What is a chewing gum for instance?

Hook's curves, determining the deformation vs. the external force applied, do not work in the case of "plastic elastine". Star-lite can be deformed only if deformation is carried out slowly, it gets elastic at higher speeds of deformation and may even crack at very fast deformations, for example when hit by a hammer. "Star-lite" is a polymer based on silicon, in which weak hydrogen bonds between molecules of the polymer get broken during the deformation.

"Star-lite", was discovered in 1943 in Dow Corning and is known also as "Silly putty". This is but an example of many novel materials with astonishing physical properties. White polymer in powder, sodium polyacrylate absorbs water immediately - it can absorb as much as 500 more than its own mass. It can absorb the equivalent of 500 times its own mass of liquid. This would be a wonderful material for disposable baby diapers.

Another polymer, polyethylene oxide, with the molecular mass of 4.000.000 atomic units (like 4 million hydrogen atoms) is sipping with infinite slowness from one glass to another.