Define the Magnets

Magnets work according to rules similar to electric charges. All magnets have two poles, north (actually north-seeking) and south poles. Like poles repel and unlike poles attract. If you break a magnet in two, you get two magnets, each with a north and south pole. Try it yourself - but not with your brother's favorite magnet.

Modern theories of magnetism explain magnetic materials as  materials in which the magnetic domains in the material are aligned. Magnetic domains are each about an area of about 10 m by 10 m or 1020 atoms or molecules of the material. The more consistently these domains line up, the stronger the magnetic field of the material. This helps us explain why dropping or heating magnets can weaken them. Dropping a magnet can realign its domains. Kinetic theory explains that as a material is heated up, the atoms gain more vibration energy, which can also randomize the alignment of a material's magnetic domains.

Magnetic materials are ones that are attracted to a magnet such as iron, nickel and steel. Some of these materials can be temporarily magnetized by contact with a strong magnet. Nonmagnetic materials are ones not affected by a magnet such as glass, wool, aluminum or brass.