Seeing how a magnet works
Here is something to try. Tie a piece of thread to one end of a paper clip. Bring the other end of the paper clip close to the end of a magnet while still holding the thread. You will find that the paperclip tugs on the thread even before it touches the magnet. Now pull the paper clip off the magnet and bring it close again but do not let them touch. Raise the magnet above the paperclip and the paper clip will follow. You should be able to make the paperclip appear to float in the air just below the magnet. How can this happen?

At the end of each magnet is a magnetic pole. This is the place where the magnetic power is very strong. When a magnetic object, such as a steel paper clip, is brought near the end of a magnet, pulling forces from the pole act on it. If the object is free to move it jumps on the end of the magnet. If the object is held in place, like your paperclip on a thread, it simply pulls as hard as it can towards the magnet. Every object on the Earth is pulled by another force. This force is called gravity. It pulls everything down to the ground. The paper clip on the thread is pulled by gravity but when it is held below a magnet it appears to float for a simple reason. The pulling power of the magnet on the paper clip is stronger than the pulling power of gravity.

However, if you raise your magnet too far above the paper clip, the paper clip falls. The reason for this is that the strength of the magnetic force varies. It is strongest at the pole but as you move away from the pole it becomes weaker and weaker. When you raise the magnet you are making the distance between the magnet and the paper clip wider. The magnetic force at this distance is too weak to hold up the paper clip so the pull of gravity takes over and the paperclip falls.

If you take another paper clip and add it to the end of a magnet, the paper clip hangs down. When you bring another paper clip to the one that is already hanging there, something odd happens. The second paperclip hangs from the first as if the first paper clip was a magnet. In fact the first paper clip behaves like a magnet ? as long as it is touching the end of a real magnet. You may be able to add a third and fourth paperclip and make a chain which hangs down from the end of the magnet. Each paperclip hangs there because the one above is behaving as a magnet.

As you make your paperclip chain you should notice that each paper clip is held less firmly than the one above. Eventually when you try to make your paperclip chain really long, the paper clips will not stick at all. The reason for this is that the magnet's power weakens with distance. The paperclips at the end of a chain of four or five will not stick because at this distance the magnetic power is too weak to hold them.

These experiments on paperclips show that there are magnetic forces around a magnet but they cannot be seen. Although the forces can never be seen, there is a way of looking more closely at what they can do. This can be done in the following way. A magnet is laid on a table. A white card is laid over the magnet and kept level. A pepper pot containing tiny specks of metal called iron filings is shaken over the paper. As each speck of metal hits the paper it meets a push and pull from the magnet. The iron filings form lines spreading out from the ends like the pieces in a fan. Around the sides of the magnet the iron filings form loops that connect one end of the magnet to the other. As to be expected, the iron filings which are furthest from the magnet are unaffected by its power and remain in pale grey clumps.

Next time you play with a magnet, think about the way the magnetic forces spread out around the magnet. Remember they are strongest close to the magnet and become weaker as you move further away.

Does the pull of gravity vary like a magnetic force?
Yes, it does. The pull of gravity is strongest close to the Earth and becomes weaker as you travel out into space. There is a place out in space where you are no longer pulled down by the Earth's gravity just as there is a place at a distance from a magnet where a paperclip is no longer pulled to the magnet.

Is gravity made by a magnet in the Earth?
No. Gravity is affected by the size of an object. Everything has a force of gravity, which can pull on other things. However this force is so weak that it cannot be felt or pull anything unless the object is huge ? like a planet or a star. All other things, like humans, elephants and even giant trees are simply too small to have a strong force of gravity.

Can a magnet be made to float in the air?
Yes, it can. If you take two ring magnets and put them round a wooden rod you may get one to float in the air above the other. This will happen if you have the lower magnet with its north pole uppermost and the upper magnet with its north pole facing down. It will also happen if the lower magnet has its south pole uppermost and the upper magnet has its south pole facing down. The magnet will float in these conditions because the similar poles repel each other. If the north pole of one magnet and the south pole of the other magnet meet, the two magnets will snap together. This happens because unlike poles attract each other.

Have floating magnets any uses?
Yes, they have. In Japan and Australia there are trains which float above the rails owing to magnets. There are magnets under the train and on the track. They push on each other with such force that the train floats just above the track. The train is powered by electricity to make it move along the track. As the train does not touch the track and rub against the rails, it moves more easily as it makes its journey.

What are iron filings?
They are made when iron is filed down in a factory. They form a fine metal dust like the fine wood dust made when you use sandpaper to smooth a piece of wood.

Are iron filings safe to use?
You must use them with care. They can make the skin sting and if they get in the eyes they cause pain. The experiment in the story is best done by school children letting
the teacher put the iron filings in a plastic bag then seeing how the iron filings arrange themselves when the bag is placed over a magnet.

What would happen to the iron filings if two magnets were used?
This would depend on how the magnets were arranged. If two north poles or two south poles were brought together, the iron filings between them would push out to the sides. This would leave a clear space between the poles. If a north pole and a south pole were brought together the iron filings would form almost straight lines between the two poles.

What would happen if a horseshoe magnet was tested with iron filings?
The iron filings would form loops, which arched between the ends of the magnet. They would also form lines inside the horseshoe that connected one side of the horseshoe to the other.