Everyday materials

An object is a thing; a material is what it is made of. A spoon can be made of metal, wood or plastic. Each material has properties – hard or soft, stiff or bendy, waterproof or absorbent, see-through or not – and we choose materials whose properties suit the job.

Key facts

  • Common materials: wood, metal, plastic, glass, fabric, paper, rubber, rock, brick and clay.
  • Properties include hard or soft, stiff or bendy, stretchy, rough or smooth, shiny or dull, waterproof or absorbent, transparent or opaque, strong or weak.
  • We choose a material for its properties: glass for windows (transparent), rubber for wellies (waterproof and bendy), fabric for towels (absorbent).
  • Some solid objects can change shape by squashing, bending, twisting or stretching.
  • Metals are good conductors of heat and electricity. Plastic, wood, rubber and glass are insulators.
  • Only some metals are magnetic: iron, nickel and cobalt, and steel (which is mostly iron). Aluminium, copper and gold are not.

Worked examples

Example 1

Why are windows made of glass and not wood?

  1. A window must let light in and let us see out.
  2. Glass is transparent: light passes straight through it. Wood is opaque: it blocks light.
  3. Glass is also hard and waterproof, so it keeps out wind and rain.

Answer: glass is transparent, so light comes in and we can see out; it is also hard and waterproof

Example 2

Ella pours water onto four paper towels and measures how much each soaks up: A 35 ml, B 22 ml, C 48 ml, D 30 ml. Which is the most absorbent, and how much more does it soak up than the least absorbent?

  1. The most absorbent towel soaks up the most water: C, with 48 ml.
  2. The least absorbent is B, with 22 ml.
  3. Find the difference. 48 − 22 = 26 ml

Answer: C; 26 ml more than B

Example 3

Which of these will a magnet pick up: an iron nail, an aluminium can, a steel paper clip, a copper coin, a plastic button?

  1. Magnets attract iron, nickel and cobalt, and steel because it is mostly iron.
  2. So the iron nail and the steel paper clip are picked up.
  3. Aluminium and copper are metals but are not magnetic, and plastic is not a metal.

Answer: the iron nail and the steel paper clip

Example 4

Why do saucepans have a metal base but a plastic or wooden handle?

  1. The base must carry heat from the hob to the food: metal is a good thermal conductor.
  2. The handle must stay cool: plastic and wood are thermal insulators.

Answer: metal conducts heat well, so it heats the food; plastic and wood are insulators, so the handle stays cool to hold