Choosing the right material
Chemistry · Key Stage 1 · The School
Properties decide the job
Glass is TRANSPARENT, so windows are glass. Rubber is FLEXIBLE and WATERPROOF, so wellies are rubber. Metal is STRONG and conducts heat, so saucepans are metal. Every object around you is a decision someone made about a property.
Testing instead of guessing
Which paper towel is most ABSORBENT? Do not argue — test it. Same amount of water, same size piece, same time, then compare. Deciding how to make it fair is the hard part and the useful part.
Some choices are trade-offs
A saucepan needs to conduct heat, but the handle must not — so the handle is plastic or wood. A raincoat must keep water out but let sweat escape. Real design usually means balancing two properties that pull against each other.
Say what the job needs FIRST: it must not leak, must not break when dropped, should be light, and should be safe with food. Now score the candidates. Glass: does not leak, but breaks and is heavy. Paper: light, but leaks. Steel: strong, does not leak, but heavy and dear. Rigid plastic: light, does not leak, does not shatter. Plastic wins — not because it is the best material, but because it best fits this list.