# Why do we need poles?

The electric force is the attraction or repulsion between charges. If we for example had a metal with only positive charges, and another metal with only negative charges. The two metal pieces will then attract each other by the electric force. In an electric system, no poles is mentioned.

The magnetic force is just a relativistic side effect of the electric force, and the difference is that it is created by moving charges and acts on other moving charges. If we have the two metal pieces, they will also feel the magnetic attraction because of the particles inside the metals have motion. The two metals is then said to be magnets. However, in a magnetic system, poles is mentioned.

1. Why are there only said to be poles in magnetic systems, and not electric systems.

2. Why does a magnet always have two magnetic poles? And what is the point of introducing the concept of poles on the metal pieces mentioned above?

3. Does poles really "exist"? Are they real concepts, or are they just a way of visualising different properties?

• As far as I know magnetic poles are merely a convention to refer to two sides of a magnet, but I'm sure someone has a lot more to say about that. – QuirkyTurtle98 Jun 11 '17 at 12:22
• @QuirkyTurtle98, there's a bit more to it than that: en.wikipedia.org/wiki/Dipole – Solomon Slow Jun 11 '17 at 14:54

1. We $do$ speak of electric dipoles. For example, certain molecules give rise to an electric field outside them approximating to that dipole, a pair of equal and opposite, very close together charges. [This can be the first step in explaining why a dielectric between the plates of a capacitor increases the capacitance.]