Uses of Elements in Everyday Life and Technology
You'll be able to explain named uses from properties.
In 2023, the ABC reported that Australia mined 314 tonnes of gold, yet pure 24-carat gold is so soft a fingernail scratches it, so jewellers alloy it with copper.
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Q1 · Name two elements you've heard of outside school, where have you encountered them and what are they used for?
Q2 · Why do you think engineers need to understand an element's properties before deciding to use it in a product?
● Know
- a use for copper, aluminium, helium, silicon and carbon, and the property behind each one
- that aluminium resists corrosion because its oxide seals the surface, while rust flakes off
- that diamond and graphite are both pure carbon, arranged differently
● Understand
- why the best conductor is not always the metal that gets chosen
- why being unreactive is itself a useful property, not the absence of one
- that a substance’s properties come from how its atoms are arranged, not only from which element it is
● Can do
- explain a named use from the property that makes it work
- compare copper and aluminium and say which job each one wins, and why
- account for two different materials made from a single element
Pick up a 9-carat gold ring and a pure 24-carat gold bar, the ring stays rigid under pressure, while pure gold scratches with a fingernail, and the only difference is which elements were alloyed into each one. An element is chosen for a job because of what it does, so the useful thing to carry out of this lesson is not a list of elements but a reason attached to each one.
Copper is the standard for household wiring because three properties line up at once. It conducts electricity almost as well as silver, the best conductor there is: on a scale where silver is 100, copper scores 97, gold 77, aluminium 59, iron 17 and lead 8. It is ductile, so it can be drawn out into a long thin wire without snapping. And it corrodes only slowly, so a wire sealed inside a wall still works decades later. Silver beats copper on the first property and loses on cost; iron is cheap and loses on the other two.
Aluminium wins a different job for a different reason. It conducts only about 60 per cent as well as copper, but it is roughly a third as dense, so a length of aluminium cable weighs far less than the same length of copper. That is why the high-voltage lines strung between towers across the country are aluminium and not copper: the towers have to hold the cable up, so weight matters more than squeezing out the last of the conductivity. Inside a house, where the wire simply lies in a wall and carries nothing but itself, copper wins again.
Aluminium also survives outdoors, and the reason is worth knowing because it is not what most people expect. Aluminium does react with oxygen, quickly. But the thin layer of aluminium oxide it forms is tough, colourless and stuck fast to the surface, so it seals the metal underneath and the reaction stops. Iron rusts in the same air and the rust flakes away, exposing fresh iron to attack. Same starting reaction, opposite result, because of what the product does once it has formed.
Text description
- Carbon (C): diamond for jewellery; graphite for pencils; carbon fibre for bike frames.
- Silicon (Si): computer chips (semiconductors); solar panels (photovoltaics).
- Gold (Au): circuit boards (no corrosion); jewellery (lustrous and rare).
- Copper (Cu): electrical wire (high conductivity); water pipes (ductile and durable).
- Aluminium (Al): aerospace (low density); food cans and foil (lightweight).
- Oxygen (O): medical oxygen in hospitals; breathing (essential).
- Property determines use: conductivity, density, reactivity and melting point all matter.
Copper is used for electrical wiring because it has very high electrical conductivity, can be drawn into thin wires without breaking (ductile), and does not corrode quickly. These three properties together make copper the ideal choice for wiring. A material with only one of these properties would be unsuitable, gold conducts well but is too expensive; iron is cheap but corrodes.
Australian copper mining: Australia mines about 4 per cent of the world's copper, which puts it around eighth on the production list, well behind Chile and Peru. What Australia does hold is the ore: roughly 13 per cent of the world's known copper resources sit under this country, second only to Chile. The Olympic Dam mine in South Australia is one of the largest copper deposits on Earth. Understanding why copper is valuable, its conductivity, ductility and corrosion resistance, helps explain why copper mining is so important to the Australian economy.
'Pure elements are always better than alloys.' They are not. Pure gold (24-carat) is too soft for jewellery. Pure iron rusts too quickly for outdoor use. Alloys like 18-carat gold (gold mixed with copper and silver) and stainless steel (iron mixed with chromium) are specifically designed to improve on the properties of pure elements.
Apply: How could you use what you learned in "Named Examples" in a real-world situation?
💡 Your brain remembers better when you write it out yourself.
Click each sentence that supports the claim.
Scientific understanding of element properties shapes technology. When scientists discovered that silicon could act as a semiconductor, the computer chip industry was born. When engineers understood aluminium's low density, aircraft design changed forever. When doctors understood titanium's biocompatibility, joint replacement surgery became routine.
This is the final link in the unit's reasoning chain: atom structure → periodic table position → category → property → use. Scientific understanding at each step enables better decisions about which materials to use for which jobs.
Text description
- Li: lithium batteries for phones, EVs and laptops; light and rechargeable.
- Si: silicon chips in all digital devices; a semiconductor.
- Nd: rare-earth magnets in wind turbines and speakers; a very strong field.
- New technology drives demand for specific elements; properties determine which element fits.
Before the Hall-Héroult process was discovered in 1886, aluminium was more expensive than gold because it was extremely difficult to extract. Once scientists understood how to produce aluminium cheaply using electrolysis, it became affordable for everyday uses, drink cans, aircraft, window frames. Scientific discovery transformed a rare metal into a common material.
Australian medical technology: Australian company Cochlear uses titanium for its hearing implants because titanium is biocompatible, the body does not reject it. This application relies on understanding titanium's properties as a transition metal. Scientific understanding of element properties directly improves quality of life.
'Technology develops independently of science.' It does not. Every major technological advance in materials, from bronze age alloys to silicon chips, was driven by scientific understanding of element properties. The periodic table is not just a teaching tool; it is a roadmap for technological innovation.
is used in drink cans because it is and does not rust. is used in building frames because it is .
Use the Element Uses Matcher interactive below. What is one thing you learned from using it?
Text description
- Copper: property, high conductivity; use, electrical wiring.
- Aluminium: property, low density; use, aircraft, cans.
- Helium: property, less dense than air; use, balloons, diving gas.
- Silicon: property, semiconductor; use, computer chips.
- Carbon (graphite): property, conducts, soft; use, pencils, electrodes.
- Gold: property, unreactive, malleable; use, jewellery, electronics.
Copper and aluminium are both useful, but not for the same reason, and the clearest way to see that a reason is doing real work is to meet an element whose reason is nothing like a metal's.
Helium sits in Group 18, the far right-hand column, and it is useful almost entirely because of what it does not do. It does not react. Helium will not burn, will not combine with the metal of a container, and will not change into anything else, which is what the word inert means. It is also extremely light: a litre of helium weighs about a sixth of what a litre of air weighs, so a balloon filled with it floats.
Those two properties have to be read together, because on lightness alone hydrogen beats helium. Hydrogen is lighter still and gives more lift, and weather balloons were once filled with it. Hydrogen also burns fiercely, and in 1937 the hydrogen-filled airship Hindenburg caught fire and was destroyed in about half a minute. Helium gives up a little lift and cannot burn at all, and for anything carrying people or expensive instruments that trade is worth making.
Being inert is also why helium does a job that has nothing to do with floating. Liquid helium boils at about −269 °C, colder than any other liquid, and hospitals use it to keep the magnets inside an MRI scanner cold enough to work. A substance sitting against a magnet for years has to be one that will not attack it, so the property that makes helium safe in a balloon is the same property that makes it usable in a scanner.
is useful in wiring because of conductivity, while is useful in aircraft because of its low density.
Improve a weak paragraph by replacing unsupported example lists with stronger property-use sentences.
Every example so far has paired one element with one set of properties. Carbon breaks that pattern, and it is the strongest evidence in the unit that properties come from structure and not from the name of the element.
Diamond and graphite are both made of nothing but carbon atoms. No other element is present in either. Yet diamond is the hardest natural material on Earth and graphite is soft enough to leave a mark on paper when you drag a pencil across it. Different forms of one element like this are called allotropes.
The difference is how the atoms are arranged. In diamond every carbon atom is joined to four neighbours in a rigid three-dimensional framework, so there is no direction you can push in without pushing against the whole structure at once. That is where the hardness comes from. In graphite each atom is joined to only three neighbours, in flat sheets, and the sheets are held to each other very weakly. Push sideways and the sheets slide over one another, which is why graphite feels slippery, works as a lubricant, and comes off on the page.
The same difference in arrangement decides whether each one carries electricity, and here the answer surprises most people. Graphite conducts; diamond does not. In graphite one electron per atom is not tied up holding the sheet together and is free to travel along it, so a current can flow, which is why graphite is used for the electrodes in furnaces and batteries. In diamond every electron is locked into the framework, so there is nothing free to move, and diamond is an insulator.
Carbon has other arrangements too. Buckminsterfullerene is sixty carbon atoms closed into a hollow ball, and carbon fibre is long chains of carbon aligned in one direction, which is what makes a bike frame stiff along its length while staying light. One element, five materials, and the only thing that changed was the arrangement.
Find the weak reasoning in this paragraph.
- Copper is useful because it is famous.
- Aluminium is useful because it is light and does not rust easily.
- Helium is useful because it is less dense than air.
- Silicon is useful because it is a semiconductor.
Choose two named elements from the lesson and explain one use for each from a property.
At the start of this lesson, you were asked about BHP mining over 250 million tonnes of iron ore from the Pilbara each year, and whether you can name two elements you have already encountered today and explain what they are used for.
Now that you have worked through everything, write your answer below. How has your thinking changed, and what surprised you most?
Q1. Explain one everyday or technology use of a named element from this lesson using a property-based reason.
Q2. Compare two named elements from the lesson and explain why they are useful for different reasons.
Q3. Diamond and graphite are both made of nothing but carbon atoms, yet one is the hardest natural material and the other is soft enough to write with. Explain how this is possible, and say what it shows about where a substance’s properties come from.
Model answers (click to reveal)
Model Answers
-Multiple Choice
1: A. Aluminium is about a third as dense as copper, so the towers hold up far less weight; the lower conductivity is worth trading away.
2: C. Both metals react with oxygen. Aluminium oxide clings to the surface and seals it, so the reaction stops; rust flakes off and lets the attack continue.
3: D. Hydrogen is lighter and lifts more, but it burns. Helium cannot burn, and that safety is worth the small loss of lift.
4: B. In graphite one electron per atom is free to travel along the sheet, so current flows. In diamond every electron is tied into the framework.
5: A. Copper scores 97 to silver’s 100, close enough that cost decides.
Short Answer 1
Example: Copper is used in wiring because it conducts electricity well. The property gives the scientific reason for the use.
Short Answer 2
Example: Copper may be useful because conductivity matters, while aluminium may be useful because low density matters. This shows that different elements can be useful for different reasons.
Short Answer 3
Diamond and graphite are allotropes: different arrangements of the same element. In diamond each carbon atom is joined to four neighbours in a rigid three-dimensional framework, so a push in any direction is resisted by the whole structure, which is why it is so hard. In graphite each atom is joined to three neighbours in flat sheets that are only weakly held to one another, so the sheets slide and the material feels soft and slippery. Since the element is identical in both, the properties cannot come from which element it is. They come from how the atoms are arranged.
Model answers (click to reveal)
Model Answers
-Multiple Choice
1: A. Aluminium is about a third as dense as copper, so the towers hold up far less weight; the lower conductivity is worth trading away.
2: C. Both metals react with oxygen. Aluminium oxide clings to the surface and seals it, so the reaction stops; rust flakes off and lets the attack continue.
3: D. Hydrogen is lighter and lifts more, but it burns. Helium cannot burn, and that safety is worth the small loss of lift.
4: B. In graphite one electron per atom is free to travel along the sheet, so current flows. In diamond every electron is tied into the framework.
5: A. Copper scores 97 to silver’s 100, close enough that cost decides.
Short Answer 1
Example: Copper is used in wiring because it conducts electricity well. The property gives the scientific reason for the use.
Short Answer 2
Example: Copper may be useful because conductivity matters, while aluminium may be useful because low density matters. This shows that different elements can be useful for different reasons.
Short Answer 3
Diamond and graphite are allotropes: different arrangements of the same element. In diamond each carbon atom is joined to four neighbours in a rigid three-dimensional framework, so a push in any direction is resisted by the whole structure, which is why it is so hard. In graphite each atom is joined to three neighbours in flat sheets that are only weakly held to one another, so the sheets slide and the material feels soft and slippery. Since the element is identical in both, the properties cannot come from which element it is. They come from how the atoms are arranged.
● Examples
Named elements help you practise the rule clearly.
● Technology
Scientific understanding supports real-world applications.
● Reasoning
Use property-based explanations, not unsupported lists.
● Next
The next lesson adds compounds and compares them with elements.