While he was investigating the magnetic field, Öersted carried out the experiment illustrated in the visual on the left. The compass initially points north, but closing the circuit changes its direction, and it points in a direction perpendicular to the current.

   What do a magnetite magnet and a current have in common? We will answer this question later in this unit. For now, let us just note that, if electric currents, that is, charged particles in movement, create a magnetic field, then it is logical to assume that they will be affected by the magnetic fields created by other moving charges or magnets.