Materials and Their Properties
Every object is made from one or more materials, each with different properties that make it useful for different jobs.
Comparing properties
Materials can be hard or soft, bendy or stiff, waterproof or absorbent, transparent or opaque, magnetic or non-magnetic. Metal is hard and a good conductor; only some metals, like iron and steel, are magnetic — most metals, such as aluminium, copper and gold, are not. Rubber is soft and bendy; glass is hard and transparent.
Choosing the right material
An umbrella is made from waterproof fabric, not absorbent cotton, because its job is to keep water out — the material is chosen to match the properties needed.
Practice
Why is glass, not wood, used to make windows?