Materials And Their Working Properties

A cold chisel and a spanner are both made of steel, and if you use one as the other you will break something. The chisel is hard enough to cut steel and would shatter if you used it as a lever; the spanner bends before it breaks and would be blunt in a minute if you hit it with a hammer. Same element, same appearance, different material, because a fraction of a per cent of carbon and a few minutes in a furnace changed which properties the steel has.

This is the largest topic in the core technical principles and it is the one every other topic leans on: you cannot select a material, choose a process, apply a finish or justify a prototype without it. You will learn the main categories and types of papers and boards, of natural and manufactured timbers, of metals and alloys, and of polymers, and then the physical properties, which are absorbency, density, fusibility and electrical and thermal conductivity, and the working properties, which are strength, hardness, toughness, malleability, ductility and elasticity. The specification is explicit that the properties are examined in relation to the main categories rather than to each named material, which tells you exactly how deep to go. This is core technical principles content, examined in Section A of Paper 1, and it supplied more specimen questions than any other topic.