Expert: Steve Nelson - 7/16/2008

Question
How can you find out which is the north-seeking and the south-seeking pole of a magnet? I know that you can suspend the magnet and it will point north but what is fundamentally different between the poles?

For example where there is no magnetic field can you still tell the poles apart?

Answer
Yes and no.  In that you don't need an external magnetic field to move the magnet, you can use the magnet's field to exert force on a wire.  You can also use a Hall probe (current flowing through a piece of material creates a voltage across it in a magnetic field, the direction of that voltage depends on the direction of the magnetic field).  Doing so will depend on the design of the magnetic field, but basically it's possible.