How can you determine the polarity of unlabeled magnet?

The polarity of an unlabelled magnet is determined by the following methods.
First method:
Suspend the magnet freely with the help of a thread so that it can oscillate freely. When the magnet comes to rest, one end always points towards the northern end of the earth. This end of the magnet is thus called the North pole. Similarly, the other end of the magnet pointing towards the south end of the earth will be a South pole.
Second method:
Take a labeled magnet. Brought North pole of this labeled magnet near an unlabeled magnet, if it attracts the unlabeled magnet then the end of the magnet will be North pole, so label it. If there is repulsion between the two magnets then it will be the south pole.
See Also: magnetic materials