Magnetism

​Magnetism is a characteristic of magnets, that causes attraction or repulsion.

It is present because of the Earth's magnetic field.

​Each magnet has it's own magnetic field within which magnetic materials are attracted. Magnetic materials are almost always metals. Many metals are magnetic, but the main ones are:

Iron, Nickel, and Cobalt. (Fe,Ni,Co)

​These are the basics of magnetism.

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​Magnetic fields are the area in which magnetic materials are attracted to magnets. The bigger the magnet, the stronger the field is. The field is also strongest at the poles. The poles are at the north and south of the magnet, and are also called the north and south poles respectively.

North poles repel other north poles, and the same with south poles. But North and south poles attract each other.​

​When a wire made of magnetic material is coiled into turns, and an electric current of a battery is passed through it, it becomes magnetic. These are electromagnets, and they are not as strong as normal magnets but will attract smaller materials and are easier to make. They can be switched on and off with starting and stopping the current flow. The magnetic field around an electro-magnet is cylindrical. Electro magnets can be made much stronger by adding an iron core to the coil of wire. They can also be made stronger by:

Adding more turns to the coil of wire

Making the batteries stronger or adding more batteries​

​The electromagnets described in the previous slide are Temporary magnets as they can be switched on and off. Meanwhile, most other magnets are permanent, meaning they never lose their magnetism, even when broken, the two pieces will both become weak magnets.