Magnetic & Non-Magnetic Substances

Materials that are attracted by a magnet are known as magnetic substances. e.g. iron, steel, nickel, cobalt, manganese, alloy of metals. They are also called ferromagnetic substances.

A ferromagnetic material has a high and positive magnetic susceptibility. The magnetic susceptibility of a ferromagnetic material is a measure of how strongly it’s attracted to a magnetic field. Ferromagnetic materials have a high susceptibility because they’re made up of atomic magnets that can be easily lined up by an external field.

Materials that are not attracted by magnets are called non-magnetic substances. e.g. glass, wood, rubber, tin, aluminium. They are also called non-ferromagnetic substances.

Magnetism is a force exerted by electric charges in motion that allows them to attract/repel other moving charged particles or it is the force exerted by magnets when they attract or repel each other. The magnetism of a magnet is concentrated at the poles of the magnet.

All matter consists of tiny units known as atoms, that have particles that carry electric charges, called electrons. These electrons circle the nucleus of an atom, generating an electric current, causing each electron to act like a microscopic magnet.

In non-magnetic substances, equal numbers of electrons spin in opposite directions, which cancels out their magnetism.

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.

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.