Q. Why do some plastics melt then burn when heated, and others only burn?
A. There are two types of plastics. The first thermoplastics are those which are weaker in structure and can be melted and reshaped again and again (e.g. the plastic in margarine containers). The second type of plastic is stronger and will not melt but will eventually burn if they get too hot (e.g. the plastic in saucepan handles).
Q. How is bullet-proof glass made?
A. Laminated or bullet-proof glass is made by adhering layers of glass and acrylic. People who live near noisy freeways use it in their windows to block out the noise. Also high rise buildings have it to withstand wind extremes and to stop people falling out accidentally.