Question

How does magnetism work?

Answer 1

Magnetism is one aspect of the combined electromagnetic force. It refers to physical phenomena arising from the force caused by magnets, objects that produce fields that attract or repel other objects. Magnetism is the force exerted by magnets, objects that repel or attract each other. This powerful physical phenomenon is one component of electromagnetism, one of the fundamental forces of nature.

Magnetism is caused by the motion of electric charges.

Every substance is made up of tiny units called atoms. Each atom has electrons, particles that carry electric charges. Spinning like tops, the electrons circle the nucleus, or core, of an atom. Their movement generates an electric current and causes each electron to act like a microscopic magnet.

In most substances, equal numbers of electrons spin in opposite directions, which cancels out their magnetism. That is why materials such as cloth or paper are said to be weakly magnetic. In substances such as iron, cobalt, and nickel, most of the electrons spin in the same direction. This makes the atoms in these substances strongly magnetic—but they are not yet magnets.

To become magnetized, another strongly magnetic substance must enter the magnetic field of an existing magnet. The magnetic field is the area around a magnet that has magnetic force.

All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The force generated by the aligned atoms creates a magnetic field. The piece of iron has become a magnet.

Some substances can be magnetized by an electric current. When electricity runs through a coil of wire, it produces a magnetic field. The field around the coil will disappear, however, as soon as the electric current is turned off.