Choosing materials and components
Design & Technology · Key Stage 2 · The School
Properties, not names
Choosing a material is choosing PROPERTIES: strong or weak, stiff or flexible, heavy or light, waterproof or absorbent, cheap or costly, easy or hard to shape. Ask what the product must survive — being dropped, getting wet, being washed, holding heat — and the shortlist writes itself. Starting from "I'll use wood" is starting from the answer.
Functional and aesthetic
Some reasons are FUNCTIONAL: it must not bend, must not rust, must be food-safe. Some are AESTHETIC: it should feel warm, look handmade, match a colour. Both are legitimate and they are not the same, so keep them apart when you explain a choice. Trouble comes from an aesthetic reason quietly overruling a functional one — a beautiful handle that gets too hot to hold.
Everything costs something
No material is best at everything, so every choice is a TRADE-OFF. Steel is strong but heavy and rusts. Aluminium is light and does not rust but costs more and is softer. Plastic is cheap, light and waterproof but weakens in sunlight. Naming what you gave up is what makes a choice a decision rather than a preference. Working the material itself happens in a workshop with an adult — this lesson is the choosing.
STEEL: strong, cheap, repairable, comfortable ride, heavy, rusts. ALUMINIUM: light, does not rust, stiff — harsher ride, harder to repair. CARBON FIBRE: lightest and stiffest, expensive, and can fail suddenly rather than bending. For a child's first bike, steel wins on cost and durability; for a racer, carbon. There is no best material here, only a best fit for a named user and budget.