Why there are magnetic fields Here's the usual way in which magnetic fields and forces are presented: current-carrying wires are electrically neutral (there are just as many electrons flowing as there are stationary metal ions) currents create magnetic fields magnetic fields exert forces on moving charges: (where the choice of units may require an additional multiplicative constant to be included in the force law) A diagram: notice that the moving charge experiences a force directed away from the wire, just as if it were being repelled by a wire carrying a net positive charge.
(as many electrons; flowing; ) (that the moving charge experiences a force; directed; away from the wire) (magnetic fields and forces; are presented; ) (a wire; carrying; a net positive charge) (an additional multiplicative constant; to be included; in the force law)
as many electrons that the moving charge experiences a force magnetic fields and forces a wire an additional multiplicative constant
flowing directed are presented carrying to be included
away from the wire
a net positive charge
in the force law