121 Magnetism

Magnets are materials that attract certain materials. Materials attracted by a magnet are referred to as magnetic. Many compounds that contain iron are magnetic. Magnets can be made of iron compounds or more exotic mixtures such as aluminum, nickel, and cobalt as in alnico magnets. Magnets are typically made of metallic compounds.

Magnets produce a magnetic field.

Observe a magnet and iron filings. Sketch the field lines.

magnet North South

magnet North South

Magnets always attract magnetic materials. Magnets, however, can attract or repel other magnets.

This leads to the model that magnets have two "ends." The planet earth also has a magnetic field. When allowed to movely freely, magnets align themselves with the field. The end of the magnet that points north is called the north pole of the magnet.

Poles that are the same repel each other. "Likes repel."

magnet S N N S

Poles that are different attract each other. "Opposites attract."

magnet S N S N

Demonstrate a Faraday coil with a magnet, a coil, and a microammeter, if available.