# Science Site

## What is Magnetism?

Published on Jul 15, 2016

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Playing with my magnet set was the best way I could imagine spending my summer vacations when I was small. There were so many things that I was able to do and so many questions that kept on piling up as I proceeded through the simple playing methods described in the manual. Eventually, I was able to get all those questions answered and I enjoyed the satisfaction in having my curiosity quenched. Magnetism is a fundamental phenomenon that is very evident in nature. A simple compass needle is an important example of magnetism, although most of us do not even know how it works.

### South Pole and North Pole

A magnet has two ends called the South and North Poles. Every magnet has an invisible field around it called the magnetic field which consists of lines of force of magnetism. These lines emanate from the North Pole and terminate at the South Pole, always. If you take a magnet and cut it into half, you will not get a magnet with one of the poles only. Instead, those two pieces will continue to act as a magnet, each of them gaining a pole which you might have thought you got rid of. The best way to observe these lines of force is to spread iron filings over a paper and place a magnet beneath it. The filings will take the shape of the lines of force that make up the magnetic field.

### Magnetic force

A moving electron displays the characteristics of both: an electric field as well a magnetic field in the surrounding space. When this moving electron comes closer to an electricity carrying wire, the electron will feel a force acting on itself and so will the wire. This is because of the interaction of their respective magnetic fields. If the current and the electron are moving in the same direction, their magnetic fields will interact such that they will be repelled from each other. On the other hand, if they are moving in opposite directions, they will attract each other.

### Temporary magnetism

In my magnet set the most fun experiment was to hammer a nail while keeping it pointed towards the North Pole. This created a temporary magnet which I could have fun with. The effect would eventually wear off. This property of materials is usually referred to as paramagnetism.

### Electromagnets

Electromagnets are those magnets which are created with the help of electricity. As soon as the circuit is completed and switched on, the current flows through the, let’s say, nail and this sets up a magnetic field around the nail. When the switch is shut off, the magnetic field instantaneously dies off.

### Two ways to be magnetized

There are basically two ways in which magnetism can be achieved. One of them is electric current and the other one is spin magnetic moments. What are spin magnetic moments? Electrons by virtue of their spinning gain certain magnetic properties which are referred to as spin magnetic moments. It is an important concept in physics which is studied in more depth for applications in quantum mechanics.