More than three-quarters of all elements are metals. They share many properties. Nearly all metals are solid at room temperature. Many are strong and hard, which makes them useful for building structures and machines, such as bridges and cars. They also conduct heat and electricity well. Some metals, such as sodium and calcium, are soft, while mercury is a silvery liquid at normal temperature.

Uses of metals

Metals such as steel (an alloy of iron) and aluminium alloys are very strong, so they are used in construction, vehicles, rail tracks, pipes and tools. Aluminium, copper and iron are good conductors of heat, making them useful for pans. Electrical power grids often use cables (bundles of wires) made of aluminium. Electrical appliances use wires made of copper. Battery casings are often made of steel. The tiny, coiled filament inside a light bulb is made of tungsten. Silver and aluminium are used for mirrors.

Iron and steel

Iron is found in the ground mixed with other elements in rock called “iron ore”. A process called smelting is used to take the iron out of the rock. The iron ore, along with limestone and coke (made from coal) is heated to a high temperature in a blast furnace. The iron turns into a liquid. It collects at the bottom of the furnace and runs out. Waste liquids, called slag, float on top of the molten iron and are poured away.

The iron is then used to make steel, an alloy (see below). It is much stronger than iron. Steel contains carbon and other metals such as manganese, chromium or nickel. It is used in making buildings, bridges, tools and machines.

Some metals, such as gold, silver and platinum, are rare. This makes them valuable. They are prized both for their rarity and for their beautiful colour and sheen. They are used in making jewellery.

Alloys

Metals can be mixed with other other substances to make new metals called alloys. Steel (see above) is an alloy. Some coins are made of an alloy of copper and nickel. Bronze is an alloy of copper and tin. Titanium alloys are very lightweight and are ideal for making mountain bike frames. Aluminium is a light, soft metal, but its alloys are used to make parts for planes and other vehicles.