You may haven’t known that but all materials in the world reveal some magnetic properties, so one can classify any media by the behavior in the external magnetic field.
Here you can see a typical scheme of the field created by a permanent rod-shaped magnet. Black lines (called magnetic force lines) show the direction of the field in space. The density of lines represents the strength of the field. The denser the lines – the stronger the field. By agreement the direction of the magnetic field outside magnet is chosen to be from the north pole to the south pole. To be honest poles are just a way of saying that a field has a certain direction, in fact there are no poles of course.
