3 COMMON GROUPS OF MATERIALS

METALS
Gold, brass, silver, iron, copper, lead and aluminium

eg: scissors, nail, hammer, teaspoon, aluminium gate, coin, trumpet, key

CERAMICS
Pottery, glass and porcelain

eg: glass, porcelain tea cup, pottery jar

POLYMERS
Plastic, rubber, nylon, wood, cotton and fabric

eg: polystyrene cup, plastic ball, shirt, jersey, brick, socks

The materials in each group have properties the are similar. A property tells us what the material is like.

Properties of cermaics (clay and glass)
They are usually brittle and can break easily.

More properties of metals

Metals are also malleable. The shape can be changed by pressing and squashing it. When metals are heated they can be hammered into different shapes. Look at the flat round shape of a gold medal.

Metals are ductile. Like chewed bubblegum you can pull it to form a long thread without breaking it.

Melting point
temperature at which something melts

Properties of non metals
Non metals like glass, clay and chald. Chalk is dull. If you dropped hcalk, glass or caly it would break. The material is brittle.

Uses of metals
More properties
Metals conduct (transfer or carry) heat energy
Some metals are magnetic
Only iron rusts but some metals tarnish or become dull

A metal spoon conducts heat better than a plastic or wooden spoon. Non metals such as wood and plstic do not conduct heat very well.
Metals are good conductors of heat. This is why we use it to make pots.

We use the magnetic properties of metails in different ways.
Magnetic power drives some hairdryers. Some trains are driven by magnetic power
Magnets make it poossible for television sets and radios to produce sound
Computers use magnets to store information

An electromagnet uses electricity to beocme magnetic. When electricyt is switched on, iron and steel stick to the electromangnet. A crane witha powerful electromagnet can life up scrap iron and steel from a scrap heap.

A metal loses its shine and strength when it rusts. Copper, brass, aluminium, stainless steel and gold do not rust. However these tarnish. They have to be cleaned and rubbed to keep them shiny.

We use gold to make jewellery, iron to make buildings and bridges, tin to make food cans, copper to make electric wires, silver to make knives, forks and spoons.