Basic 6 · Science · Materials
Uses of Metals in Everyday Life
In this topic you will investigate the uses of metals in everyday life and link each use to the properties of the metal.
By the end of these notes you should be able to:
- Name common metals and alloys and their uses
- Link uses to properties
- Explain how metals are protected from rusting
What you already know
- Properties of metals
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
- Strand
- Diversity Of Matter
- Sub-strand
- Materials
- Indicator
- B6.1.2.1.2 – Investigate the uses of metals in everyday life and link the uses to their properties
Introduction
Why are electric wires made of copper, cooking pots of aluminium and jewellery of gold? Each metal is chosen because its properties suit the job.
1. Metals and Their Uses
| Metal | Use | Property that makes it suitable |
|---|---|---|
| copper | electric wires and cables | excellent conductor of electricity; ductile |
| aluminium | cooking pots, window frames, aircraft bodies | light, conducts heat, does not rust |
| iron/steel | building rods, bridges, nails, cutlasses | strong and hard |
| gold | jewellery, coins, electronics | lustrous, does not tarnish, good conductor |
| silver | jewellery, mirrors | lustrous, reflects light |
| zinc | coating iron roofing sheets (galvanising) | protects iron from rust |
| lead | car batteries | dense, does not corrode easily |
| tin | coating food cans | does not react with food |
2. Alloys
Alloy: A mixture of a metal with other metals or elements, made to improve its properties.
| Alloy | Made from | Use |
|---|---|---|
| steel | iron + carbon | buildings, cars, tools |
| stainless steel | iron + chromium + nickel | spoons, sinks; does not rust |
| brass | copper + zinc | door handles, musical instruments, bullet cases |
| bronze | copper + tin | statues, medals |
3. Preventing Rust
Iron and steel rust when they react with water and oxygen, forming a reddish-brown layer that weakens them. Rust is prevented by painting, oiling or greasing, galvanising (coating with zinc), tin plating, and using stainless steel. Roofing sheets are galvanised, and gates and window bars are painted.
4. Metals and the Economy
Gold has been mined in Ghana for centuries and is a major export. Aluminium is made from bauxite at the VALCO smelter in Tema. Metal craftsmen (blacksmiths and goldsmiths) make tools, jewellery and gold weights. Recycling scrap metal saves energy and reduces mining.
Scrap dealers who collect old metal in our communities play an important role, because recycled aluminium needs far less energy than making new aluminium from bauxite.
Safety: Handle sharp metal sheets and rusty nails carefully. A cut from a rusty object can cause tetanus, so get medical help.
New words
- alloy
- A mixture of a metal with other elements.
- galvanise
- To coat iron with zinc to prevent rust.
- rust
- Reddish-brown layer formed when iron reacts with water and oxygen.
- tarnish
- To lose shine.
- bauxite
- The ore from which aluminium is obtained.
- scrap metal
- Used metal that can be recycled.
Summary
- Each metal is used because of its properties.
- Alloys such as steel and brass improve on pure metals.
- Painting, oiling and galvanising prevent rust.
- Metals are important to Ghana's economy.
Class activity: Metal Survey
- Walk around the school and list ten metal objects.
- For each, name the metal and the property that makes it useful.
- Note any rusting and suggest how to prevent it.
You need: Aluminium cooking pot, Steel spoon, Copper wire
Exercises
Answer in your exercise book first, then check your answers.
1. Electric wires are usually made of…
- A. copper
- B. gold
- C. lead
- D. tin
Show answer
Answer: copperGood conductor and ductile.2. Roofing sheets are coated with zinc to…
- A. prevent rust
- B. make them heavy
- C. make them shine only
- D. make noise
Show answer
Answer: prevent rustGalvanising.3. Brass is an alloy of…
- A. copper and zinc
- B. iron and carbon
- C. copper and tin
- D. gold and silver
Show answer
Answer: copper and zincUsed for door handles.4. Aluminium is used for cooking pots because it conducts heat.
- A. True
- B. False
Show answer
Answer: TrueAnd is light.5. Stainless steel rusts quickly.
- A. True
- B. False
Show answer
Answer: FalseChromium and nickel prevent rust.6. Aluminium is obtained from the ore ______.
Show answer
Answer: bauxiteMined at Awaso.7. State three ways of preventing rust.
Show answer
Answer: Painting, oiling and galvanising (or tin plating, stainless steel).Any three.8. Why is gold used for jewellery?
Show answer
Answer: It is lustrous, does not rust or tarnish, and is malleable enough to shape.Properties.
Homework
- Find an object at home that is rusting. Describe how you would protect it.