Uses of metals
Uses of aluminium and copper linked to their properties.
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Learning objectives
What you need to be able to do
Teacher-mapped phrasing — check against the official Cambridge syllabus for exact wording.
- 9.2.1Explain the uses of aluminium and copper in terms of their properties.
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Uses of aluminium and copper
Choosing a metal for a job means matching its properties to what the job needs — the IGCSE syllabus focuses on aluminium and copper as the two key examples.
Aluminium
Aluminium has a low density, is strong (especially when alloyed), resists corrosion (a thin, tough layer of aluminium oxide forms naturally on its surface and protects the metal underneath from further reaction), and is a reasonably good conductor.
These properties make it ideal for:
- Aircraft manufacture — low density keeps the aircraft light, while alloying gives sufficient strength.
- Overhead power cables — low density means lighter cables needing less support, and it conducts electricity well, while corrosion resistance means it survives years of weather exposure.
- Drink cans and food packaging — corrosion resistance and low density (light, easy to transport), plus it does not react with the contents.
Copper
Copper is an excellent conductor of electricity, is ductile (easily drawn into wires), and resists corrosion reasonably well in normal conditions.
These properties make it ideal for:
- Electrical wiring — excellent conductivity combined with ductility (it can be drawn into thin wires without breaking).
- Water pipes — it does not corrode easily in contact with water, and can be bent into shape without cracking.
Think of it like this
Choosing a metal for a job is like choosing a material for shoes: you would not use heavy steel-toe boots for a marathon (too dense, like avoiding aluminium for an aircraft would be wrong-headed) or thin canvas for firefighting (not tough enough) — every material choice traces back to matching specific properties to a specific demand.
Common misconceptions
- Naming a use of a metal without linking it to a specific property. "Aluminium is used for aircraft" alone is not an explanation — the property (low density) and its consequence (lighter aircraft, less fuel needed) must both be stated.
- Assuming aluminium resists corrosion because it does not react with oxygen. It does react, but the oxide layer that forms sticks tightly to the surface and protects the metal underneath from further reaction — a subtly different and important distinction.
- Confusing why copper is used for wiring (conductivity and ductility) with why aluminium is sometimes used for large overhead cables instead (its much lower density matters more there, despite copper conducting slightly better).
In the exam
- Every "explain the use" answer needs the structure: property → consequence → use. E.g. "Copper is ductile, so it can be drawn into thin wires, which is why it is used for electrical wiring."
- If two properties are relevant to one use (as with aluminium in overhead cables), mention both — questions worth 2+ marks usually expect more than one linked property.