Most substances are composed of molecules, which are made up of atoms, and atoms consist of atomic nuclei and electrons. Within an atom, electrons constantly spin and orbit around the atomic nucleus. Both of these movements generate magnetism. However, in most substances, the directions of electron movements are different and chaotic, causing the magnetic effects to cancel each other out. Therefore, most substances do not exhibit magnetism under normal circumstances.

Iron, cobalt, nickel, or ferrite, among other ferromagnetic materials, differ in that their internal electron spins can spontaneously align within a small range, forming a spontaneously magnetized region known as a magnetic domain.

After magnetization, ferromagnetic materials have their magnetic domains neatly aligned in the same direction, which strengthens their magnetic properties, thus forming a magnet. The process of a magnet attracting iron is the same as the magnetization of the iron block. The magnetized iron block is attracted to the magnet due to the opposite poles, and the iron block adheres firmly to the magnet. We say that the magnet has magnetism.