Smart putty has been available for a long time as an amusement, but this visco-elastic polymer has serious engineering applications.

Soft, stretchy and bendy when moved slowly, solid when trying to move quickly or impacted.

It has the remarkable property that it usually behaves as a soft mould-able plastic (like chewing gum), but instantly becomes a rubber if impacted and bounces like a ball. It can also float in a liquid and will form a puddle given enough time. It is a great demonstration of an unusual polymer, a useful adhesive and can be used in many creative and fun activities.

• Supplied: 100g in a plastic container.