Welcome to our educational pages. In this section, you can find out about the history, biology, chemistry and physics of copper. Additionally there are pages on copper's environmental credentials and some case studies of copper in action in industry.
You can take a virtual tour of a house which shows you the many ways copper is used inside and outside the home.
You can also access an interactive presentation on the importance of copper in the production of Euro Coins.
The roles of copper
Copper plays a vital role in shaping our lives. People have been using copper since 9000 BC. One of the reasons copper is so important is that it can be made into alloys. That means it can be combined with other metals to make new alloys, like brass and bronze. These are harder, stronger and more corrosion resistant than pure copper.
Nowadays it is prized for different qualities. It is an excellent conductor of electricity and heat; it is strong, ductile and easily joined by soldering or brazing; and it is hygienic, easy to alloy and resists corrosion.
You can find copper all over the place. In your home it is hidden away in everyday objects, including phones, water pipes, locks and electrical wiring.
Properties of Copper
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• An excellent electrical conductor
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• tough
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• An excellent thermal conductor
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• non-magnetic
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• corrosion resistant
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• an attractive colour
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• anti-bacterial
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• easy to alloy
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• easily joined
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• recyclable
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• ductile
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• catalytic
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Electrical conductivity
Copper has the best electrical conductivity of any metal, except silver. A good electrical conductivity is the same as a small electrical resistance.
Applications
Copper wires allow electric current to flow without much loss of energy. This is why copper wires are used in mains cables in houses and underground (although overhead cables tend be aluminium because it is less dense). However, where size rather than weight is important, copper is the best choice. Thick copper strip is used for lightning conductors on tall buildings like church spires. The cable has to be thick so that it can carry a large current without melting.
Copper wire can be wound into a coil. The coil will produce a magnetic field and, being made of copper, won't waste much electrical energy. Some examples of where copper coils can be found are:
Electromagnets:
Locks, scrapyard cranes, electric bells.
Motors:
Pumps, domestic appliances (washing machines, dishwashers, fridges, vacuum cleaners), cars (starter motors, windscreen wipers, electric windows), computers (disc drives, fans), entertainment systems (CD and DVD players).
Dynamos:
Bicycles, power stations.
Transformers:
Mains adaptors, electricity substations, power stations.
How copper conducts
Copper is a metal. It is made up of copper atoms closely packed together.
If we could look closely enough, we would see that there are electrons moving about between the copper atoms. Each copper atom has lost one electron and become a positive ion. So copper is a lattice of positive copper ions with free electrons moving between them. (The electrons are a bit like the particles of a gas that is free to move within the edges of the wire).
The electrons can move freely through the metal. For this reason, they are known as free electrons. They are also known as conduction electrons, because they help copper to be a good conductor of heat and electricity.
The copper ions are vibrating. Notice that they vibrate around the same place whereas the electrons can move through the lattice. This is very important when we connect the wire to a battery.
Conducting electricity
We can connect a copper wire to a battery and a switch. Normally, the free electrons move about randomly in the metal.
When we close the switch, an electric current flows. Now the free electrons flow through the wire (here, they are moving from left to right - although they still move randomly as well).
Electrons have a negative charge. They are attracted to the positive end of the battery. The free electrons move through the copper, flowing from the negative to positive terminal of the battery (note that they flow in the opposite direction to conventional current; this is because they have a negative charge).
The copper ions in the wire vibrate. Sometimes an ion blocks the path of a moving electron. The electron collides with the ion and bounces off it. This slows down the electron. Some of its energy has been transferred to the ion, which vibrates faster.
In this way, energy is transferred from the moving electrons to the copper ions. The copper gets hotter. This explains why:
• metals have electrical resistance;
• metals get hot when a current flows through them.
