Compare current induction using a south vs. a north pole of a magnet
Suitable For
Grade 5
Difficulty
1
Time Required
<24 Hours
Supervision
Advised
What’s it about?
Magnetism has a lot in common with electricity. Both have polarity – magnets have a north and a south pole which repel each other, and similar poles attract each other. Electricity has positive and negative polarity which works similar to the attraction and repulsion of magnetism.
Electrical current can only flow when there is a difference in electrical potential, not when they are alike. Observe what happens when electrical current is induced with the south and the north pole of a magnet respectively in this science experiment:
Topics covered
Milliammeter, Induction, Michael Faraday
What will I need?
- INSULATED COPPER WIRE
- BAR MAGNET
- LARGE BOLT
- MILLIAMMETER
- WIRE CUTTERS
Procedure (Method)
Magnetism has a lot in common with electricity. Both have polarity – magnets have a north and a south pole which repel each other, and similar poles attract each other. Electricity has positive and negative polarity which works similar to the attraction and repulsion of magnetism. Electrical current can only flow when there is a difference in electrical potential, not when they are alike. Observe what happens when electrical current is induced with the south and the north pole of a magnet respectively in this science experiment:
- Cut off about 100cm of insulated copper wire and ask your parents or an adult to help you strip clean the two ends of the wire from insulation using wire cutters.
- Wrap the wire in a coil around a large bolt, keeping the wire turn tight against each other and the bolt.
- Connect the two exposed ends of the wire to the terminals of a milliammeter.
- Use the north pole of a strong bar magnet to stroke along the length of the bolt or ‘coil’ in one direction only. Notice in which direction the needle of the milliammeter moves.
- Now, use the south pole of the bar magnet to stroke along the coil in the same direction and notice how the needle of the milliammeter now jumps in the other direction!
How does it work?
In this science experiment the milliameter needle moves in the direction of current flow each time a pole of the magnet is moved along the coil to indicate the flow of electricity by means of ‘induction’. When the magnet is removed, the current stops. The direction of an induced current will always oppose the change that is causing it.
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