Matching Pairs Materials for technical useOnline version What is involved in making a mobile phone? Match the following elements. by Jesús Espinosa 1 How does it work? 2 What materials is it made of? 3 How big is it? 4 What is it for? 5 How much does it cost? 6 The outer casing of mobile phones is typically made from... Plastic, aluminium and other metals plastic (polycarbonate), aluminium and magnesium. For people to talk to each other from wherever they are. The average price for a free smartphone is currently anywhere between 400€ and 800€. Nowadays the average is more than 5 inches long (12.7 cm). They work like two-way radios: the phone converts the sounds of your voice into radio signals and transmits them to another phone, which converts them back into sound.