These simulation shows a wire and the sum of the wire's magnetic field and an external magnetic field. In some cases the external field is supplied by a second wire. The force on the wire is shown by a black arrow and the magnitude of the force is shown in yellow at the bottom of the simulation when you hold the mouse button down on the wire. You can move the wire by dragging it. The current may flow either into the screen (away from you) or out of the screen (towards you).

The magnetic field vectors are shown in color with blue indicating a weaker field and black indicating a stronger field.