What’s the link between Lego blocks, zero pollution cars, disposable nappies, liquids that flow up hill, and false legs? How is this linked to the perfect recipe for slime? Mrs Crosbie’s Chemistry class attended a “Fantastic Plastic” demonstration lecture delivered by Professor Averil McDonald at the University of Glasgow on 1st September. The lecture discussed the physical properties of plastics as featured in the topic in National 4/5 ‘Properties of Plastics’ and featured many interesting demonstrations.
After a brief overview of the great variety of physical properties of plastics that make them suitable for various intriguing and surprising applications, students were reminded of the basic concepts of solid, liquids and gases and introduced to the idea of polymers consisting of long chain molecules. Polymers can exist as solid and liquids but often have properties of both (as in slime). Lively demonstrations showed the effects of increasing the temperature, crosslinking the molecules, “tangling up” the polymer chains, and dissolving them in liquids. Some examples are given to show how by controlling what happens at the molecular level, the characteristics of the final material are determined.
