Which of these contains a synthetic polymer?

• Silk
• Nylon
• Cotton

Which properties are typical of a ceramic such as a brick?

• Hard, brittle and heat-resistant
• Soft, stretchy and easily reshaped
• Flexible, springy and easily bent

A composite combines distinct materials that contribute properties to the finished material.

Wool grows on sheep and is later spun into yarn. How should its protein polymer be classified?

• Natural, because sheep make its protein
• Synthetic, because spinning creates new polymer chains
• Ceramic, because the fibres are processed into yarn

What does the polymer resin contribute to a carbon-fibre reinforced plastic bike frame?

• It supplies all the stiffness, so fibres add no support.
• It melts the fibres into a single new polymer material.
• It holds fibres in place and transfers forces.

A manufacturer adds a plasticiser to a plastic film. The film then bends more easily. What does this demonstrate?

• The additive replaces all long chains with small molecules.
• An additive can change the film's flexibility.
• The additive makes every polymer hard and unable to bend.

An engineer proposes a polymer-resin composite for a very hot machine part. What should they do before relying on its heat resistance?

• Test the finished composite at the required temperature.
• Assume its reinforcing fibres remove every limit on the resin's use.
• Assume combining materials always gives better heat resistance.

Tom says ordinary window glass must be a composite because it is hard. Does that reason show it is a composite?

• Yes. Every hard material contains reinforcing carbon fibres.
• Yes. Hardness shows that two distinct materials are present.
• No. Hardness does not show distinct constituents.