| In
1819, Hans Christian Oersted, a Danish scientist was experimenting
with electricity. |
|
 |
Oersted
noticed that a compass needle moved when a current flowed through
a wire nearby. |
|
|
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. |
 |
| 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. |
|
|
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. |
