Field line patterns

Magnets have a north pole and a south pole. Field line patterns show the direction and shape of a magnetic field. These diagrams are made using a plotting compass. In diagrams of a magnetic field the arrows on the lines show the direction from the north to the south poles.

A magnetic field is also created when an electric current moves through a coil of wire.

Plotting compasses can be used to show the shape and direction of the magnetic field created by a coil of wire.

Straight wire

Diagram showing the magnetic field lines associated with wires carrying electric current.Magnetic field lines associated with wires carrying electric current

Flat circular coil

Diagram showing the magnetic field lines around a circular coil.Magnetic field lines around a circular coil

Solenoid

A solenoid is a long thin spiral of wire used to produce a magnetic field.

Diagram showing the magnetic field lines around a solenoid.Magnetic field lines around a solenoidCross-section of wires carrying a current towards you and wires carrying a current away from you. The magnetic field lines associated with the wires are shown.Magnetic field lines associated with wires carrying electric current