This lesson introduces the vocabulary and thinking behind every material decision a designer makes: property versus material, the six material families (woods, metals, polymers, textiles, papers and boards), and the difference between physical and working properties. Pupils learn the ACCESSFM checklist, see how workshops actually test a claimed property, and work through a worked example choosing the shell and liner for a cycle helmet. It closes with smart materials, sustainability and a set of common misconceptions. A ready-to-teach PowerPoint for an hour-long Year 7 Design and Technology lesson.