20048 AC Science Year 6 Physical sciences
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Electromagnetism unplugged!<br />
Electromagnetism is a basic principle of science that has many<br />
applications for use in today's technological world. For example,<br />
doorbells, speakers, motors and even central locking systems in cars<br />
use electromagnetism. But what is an electromagnet?<br />
An electromagnet works just like a permanent magnet (likes repel and<br />
opposites attract), but only functions when an electric current is flowing<br />
through it.<br />
When electrons flow along a wire between the negative and positive<br />
terminals of a battery, they generate a small, circular magnetic field around the wire. The field is<br />
strongest close to the wire and weakens further out. The effect of the magnetic field of a straight<br />
wire is increased if the wire is coiled. This can be demonstrated by the effects a current flowing<br />
through a straight wire and a coiled wire have on a compass placed close by.<br />
I • Plan your own investigations to discover more about the strength of an electromagnetic field.<br />
Using a long iron nail as the core and staples or small paperclips, determine the effect of<br />
A the number of coils of wire on the strength of the magnetic field produced. Measure the<br />
strength of the field in paper clips.<br />
B<br />
Use different thicknesses of material for the core.<br />
What effect do they have on the strength of the electromagnetic field?<br />
Use different materials for the core; for example: aluminium, 'lead' from a pencil, plastic,<br />
C wood.<br />
What effect do they have on the strength of the electromagnetic field?<br />
Use two batteries, connected in series.<br />
D<br />
What effect does this have on the strength of the electromagnetic field?<br />
2. When you have completed your investigations, write statements to describe the relationship<br />
between the strength of the electromagnetic field generated and:<br />
(a)<br />
(b)<br />
the number of coils in the wire<br />
the thickness of the core<br />
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(c)<br />
the type of material the core is made from<br />
(d)<br />
the voltage provided to run the current.<br />
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AUSTRALIAN<br />
CURRICULUM SCIENCE (<strong>Year</strong> 6)
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