|In 1819, Hans Christian Oersted, a Danish
scientist was experimenting with electricity.
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.
should find that the compass needle changes direction to line
up with the centre of the coil because the coil behaves like
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.