Where to look for magnets
Where can you find a magnet in your home? The chances are that you can find one on your fridge door. It may be hidden behind a plastic letter, an animal or a picture with a poem. The purpose of these magnets is to hold pieces of paper, which carry notes and messages for people in the home. However, the fridge contains other magnets. If you open the fridge door you will see a rubber seal which helps to keep the cold air in the fridge from the warm air in the kitchen. Inside the rubber are small magnets. When the door is closed the magnets hold it fast without the fridge having to have a latch or lock. When the fridge motor is whirring away another magnet is in use. It is helping to keep the inside of the fridge cool. Most magnets are used in places where they are not seen.

A magnet is unusual because it has a force without you having to do anything. For example, you may have discovered how, if you rub a plastic pen with a cloth, the pen has a force, which can pick up dust and tiny pieces of paper. This force is due to electricity, which is made by rubbing. When you pick up a magnet you can feel and see the effects of its force straight away if you know what to do.

If you take a magnet off the front of a fridge door you may have to pull quite hard. Your pulling force has to be stronger than the magnetic force, which is holding the magnet to the door. When you have removed the magnet and brought it close to the door again you can feel the magnetic force pulling on your hand as the magnet tries to grip the door once again. However, if you bring the magnet close to a plastic cup or a glass, you do not feel any pulling force. If you try to stick a magnet to the side of a cereal packet, it simply falls away from the cardboard. Open the cutlery drawer and put the magnet on knives, forks and spoons and something different happens. The magnet may stick to them all.

The way the magnet behaves is due to the material it touches. Some materials are magnetic and some materials are non-magnetic. A magnetic material is one that is attracted to a magnet. There are four metals which are magnetic. They are iron, steel, nickel and cobalt. Most materials are non-magnetic. Examples of non-magnetic materials are cardboard, plastic, glass, wood and pottery. Although a non-magnetic material is not attracted to a magnet it may let its power pass through it. This is how we can use magnets on the front of a fridge to hold paper and postcards there. The force from the magnet simply passes through these materials and lets the magnet hold onto the fridge door. When this happens, the paper or postcards are trapped and held in place.

If you look around a kitchen you may find that some doors to the kitchen units have magnetic catches. When they close a magnet grips a piece of metal to hold the door shut. There may be many other magnets in the kitchen but they are hidden away like the magnet in the fridge motor.

Other things in the kitchen have motors. Some motors are large and powerful like the motors that operate a washing machine or tumble drier. Some are much smaller like the one that makes the turntable go round in the microwave oven.

The reason magnets are found in electric motors is that electricity can also turn coils of wire into magnets. Inside an electric motor is a coil of wire. It turns into a magnet when the electricity is switched on. The coil is on a spindle and can turn. The magnetic forces between the coil and the magnets in the motor push and pull on the coil and make the coil spin. This in turn makes the spindle turn. The power of the turning spindle can tumble your clothes in a dryer or turn round your meal inside the microwave oven.

Magnets are not just found in the kitchen. They are found in many pieces of electrical equipment around the home. They are found in the motors of video recorders and CD players. They are present in loudspeakers. They help form the pictures on television screens and computer screens. Without the magnets in this monitor you would see nothing here.

Are magnets just natural materials?
One kind of natural material is magnetic. It is a dark coloured rock called lodestone. If you bring steel paperclips to it, they jump onto its sides. All the magnets that you use in your home are made or manufactured. They are made by placing the metal to be magnetised in a coil of wire. Electricity is passed through the coil of wire and the metal is turned into a magnet.

Are all metals magnetic?
No. Only iron, steel, nickel and cobalt are magnetic metals. Other metals such as copper or aluminium are not magnetic. Different metals can be mixed together. This is done by heating the metals until they melt, then mixing them and letting them cool. A mixture of metals formed in this way is called an alloy. When some magnetic metals are mixed with non-magnetic metals they make an alloy which is magnetic. For example, aluminium, nickel and cobalt can be mixed together to form a magnetic alloy called alnico. When a magnetic metal is mixed with non-magnetic metals it may form an alloy which is not magnetic. For example, stainless steel is an alloy made from steel, nickel and chrome. Some pans are made of stainless steel. If you have some in your home put your fridge magnet on them. You will find it will not grip them.

What kind of electricity is made by rubbing a pen on a cloth?
This kind of electricity is called static electricity because it stays where it was formed. Another example of static electricity is seen when you rub a plastic comb and hold it near someone with long hair. The force of the static electricity makes the long hair rise off the person's head. Static electricity is not the same as the electricity that flows through wires. This electricity is called current electricity. It is made when batteries are put in the simple circuits you make in school. It is also made by generators in power stations. The electricity made in power stations is used in the mains in schools, homes and factories. It must be used with great care.

How is the electricity made in a power station?
It is made in a generator. This has magnets and coils like an electric motor. In a power station fuel such as coal or oil is burnt to boil water. The steam that is made is used to turn fan blades, which are attached to the generator. The turning fans make a magnet in the centre of the generator spin round. The spinning magnet makes a current of electricity in the coils of wire around it. This current is allowed to flow to schools, factories, hospitals and homes. The electricity that is working this computer has been
made at a power station.

Why is a magnet needed in a loudspeaker?
A loudspeaker has a cone made of card or plastic. At the centre of the cone is a coil of wire and around the coil is a magnet. When a radio or television is switched on, electricity flows through the coil and turns it into a magnet. The forces made by the coil and the magnet make the coil shake or vibrate. The shakes or vibrations are passed onto the cone. The cone passes the shakes or vibrations onto the air and sounds are made.