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 ferrites, among other ferromagnetic materials, differ in that their internal electrons can spontaneously align within a small range, forming a spontaneous magnetization region, which is referred to as a magnetic domain.

After magnetization, ferromagnetic materials have their magnetic domains neatly aligned and in the same direction, which strengthens their magnetism, thereby forming a magnet. The process of a magnet attracting iron is the same as magnetizing the iron block. The magnetized iron block and the magnet, with opposite poles, generate an attractive force, causing the iron block to firmly stick to the magnet. We then say that the magnet has magnetism.