Electromagnetism: Physics, science 1 investigation.

Essay by chevrayA+, March 2003

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The term magnet is defined as, an object made of a ferromagnetic material such as iron, with domains that are aligned one way. Thus, it has poles and a magnetic field around it. Magnets or electromagnets whose effect can be switched on and off are used in many electric machines. When any current flows, it produces a magnetic field.

Were it not for the Earth's magnetic field, all life on the planet would be killed off by cosmic radiation and cease to exist.

The creation and destruction of magnets is relatively easy to carry out. To create a magnet, a magnetic material (e.g. steel), and a solenoid are required.

Place the steel into the solenoid, connect to a direct current supply, and turn on. Then switch off the supply and a magnet is produced.

To destroy the magnet, use an alternating current. Use a solenoid as before, however, this time, first turn on the current and then push the magnetic material through the solenoid.

Then switch off the supply and the magnet is destroyed.

Hammering a magnet also is destructive and affects its power.

This is an investigation into the factors, which increase the strength of an electromagnet.

All the work will be carried out in the laboratory.

Variables that affect the strength of an electromagnet are: -

Strength of Current;

Number of coils on the solenoid;

Distance between the coils;

Internal energy of the apparatus; and

Internal energy of the surroundings;


The mass of Panel pins lifted Vs the increase in current.




Variable resistor;


Panel pins;

Iron rod;

Electronic scales and

Two glass containers.


The Investigation


(1) Make a solenoid of forty coils.

(2) Use a current of 0.5A..

(3) Set up apparatus as shown in the diagram.