Magnetism can be a difficult force to understand because we can’t see it. It doesn’t affect everything, like gravity, but magnetic fields are all around us. The earth acts like a big bar magnet with the ends at each pole, but the planet’s magnetism comes from the swirling molten iron under the crust. As a result, only metals with iron in them can be magnetised. An iron nail can be moved by any magnet that is strong enough, but you can also turn it into a magnet itself.
- Skill level:
- Moderately Easy
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Things you need
- Large magnet
- Copper wire
Understand the science behind magnets so you can appreciate what is happening with the different techniques. Metals with iron in them have what are known as magnetic “domains.” These are different parts of the metal in which the magnetic parts face in different directions, meaning there is almost no overall magnetic effect. What you are trying to do during the magnetisation of your nail is to try and get all the different domains facing in the same direction.
Get hold of another strong and permanent magnet. On one end of the magnet, rub the iron nail all the way along, from one end of the nail to the other. Take the nail off the magnet at the end, place back at the other end and start again. Don’t just rub it back and forth – this won’t work. If you do this enough times you will leave the nail with a magnetic charge and you will be able to pick up small metal objects that contain iron. This is because you are using the big magnet to align the different domains.
Take copper wire insulated in plastic and wrap it round the nail – the more turns the better. Then attach each end of the wire to the two poles of a battery. When you complete the circuit the nail will become what is known as an electromagnet. The more turns you have in the wire the stronger the magnetism will be. In this case, the electricity is forcing the domains into facing in the same direction.
Tips and warnings
- Be careful when using electricity and don't touch exposed connections with your bare hands.