# Find out the factors affecting the strength of an electromagnet.

ELECTROMAGNETISM

AIM: The aim of this investigation is to find out the factors affecting the strength of an electromagnet.

BACKGROUND KNOWLEDGE  (THEORY):

Magnetism is the tendency a metal such as iron, steel and cobalt have to attract other metals e.g. pins.

Magnetism arises as a result of the motion of charged particles called electrons in the wire. In most substances the effect of this motion cancel out, but in ferromagnetic substances they do not.

When insulated wire is wrapped round an iron nail and the ends of the wire are connected to a battery, and the nail becomes capable of picking up iron filing or paper clip. The nail is magnetised by the current in the wire. If the battery is disconnected then the clips will fall of. This is because they are not a permanent magnet; they are called temporary magnetism.

The iron filings cluster around the end of a magnet because a magnet behaves as if all its magnetism were concentrated near its ends.

These place were the magnetism appear to be concentrated are called the poles of the magnet.

INDUCED MAGNETISM   (1)

IF a piece of ferromagnetic substance is made to touch or brought near to the pole of a magnet, it becomes a magnet itself. This is called induced magnetism.

This end of the substances nearest to the inducing pole has an opposite pole inducing in it. A chain of pin can be attached to a bar magnet, with each induced pole inducing and opposite pole next to it.

If the South Pole of a magnet is brought near the bottom of the lowest pin in fig1.2, the pin will be repelled showing it is a South Pole.

THE FACTORS AFFECTING MAGNETISM STRENGTH

I will try to use scientific theories and explanations wherever possible. I will try and get a valid set of results that I can use to draw a firm conclusion from and to backup my prediction.

Here is list of all the factors, which could affect my investigation. They are:

• Current
• Numbers of coils in the wire
• Using a soft iron core
• Placing an iron or steel core inside of the coil.

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