18.1. Magnetic Fields http://www.ck12.org
half of the figure).
FIGURE 18.1
http://demonstrations.wolfram.com/ObservingMagneticFieldsWithIronFilings/
Magnetism from an Electric Current
During the early 18th century, physicists were looking for possible connections between electrical and magnetic
phenomena. In 1820, Hans Christian Oersted (1777-1851), made the discovery that a current-carrying wire created
a magnetic field.
Oersted arranged a long straight conducting wire and a compass as shown inFigure18.2 to show the magnetic field
around the wire.Figure18.3 shows iron filings aligned with the magnetic field around the wire.
FIGURE 18.2
As soon as a current was initiated in the wire, the compass needle deflected. A magnetic force must be present,
produced by an electric current! The compass needle aligned itself perpendicular to the direction of the current.
Moving the compass in a plane perpendicular to the wire showed that a magnetic field circled around the wire as in
Figure18.2 andFigure18.3.