Magnetism

The term magnetism describes a force action between two objects. These can be magnets, magnetised objects such as iron or current-carrying conductors.

A magnet has always two poles, we call this a dipole. In magnets, these are called the north and the south pole. Individual poles, so-called dipoles, do not exist.
Like poles repel and opposite poles attract each other. North poles and south poles attract each other, two north poles or two south poles repell each other.

Magnetic field

Something special about this is that the force action can happen at a distance. This can be described with the term of fields. Magnets are surrounded by a so-called magnetic field, which can be depicted by images. This model explains in which direction the magnetism acts in a specific postion. Magnetic field lines always point from the north to the south pole. Their density symbolises the strength of the field.

Ferromagnetism

Some specific materials can be magnetised. When they are close to or touch a magnet, they form a north and a south pole as well. However, they are always only attracted by the magnet because the formation of the poles is depending on the magnet. When they are detached from the magnet, they lose their magnetisation over time.