| In 1819, Hans Christian
Oersted, a Danish scientist was experimenting with electricity. |
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Oersted noticed that a
compass needle moved when a current flowed through a wire nearby. |
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If you wrap a 10 cm length
of bell wire round a pencil in a single layer coil and connect
the ends to a 3v battery, you will make a solenoid. Bring a compass needle towards this and watch
what happens. |
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| You should find that the
compass needle changes direction to line up with the centre of
the coil because the coil behaves like a magnet. |
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If you reverse the battery
terminal wires, then the compass needle should reverse. It will
still be lined up with the pencil, but in the opposite direction. |
