Most substances are composed of molecules, which are made up of atoms, and atoms consist of atomic nuclei and electrons. Within atoms, 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 their magnetic effects to cancel each other out. Therefore, under normal circumstances, most substances do not exhibit magnetic properties.

Iron, cobalt, nickel, or ferrites, and other ferromagnetic materials differ in that their internal electron spins can spontaneously align within a small range, forming a spontaneous magnetization domain, which is called a magnetic domain.

After magnetization, ferromagnetic materials have their magnetic domains neatly aligned and oriented, which strengthens the magnetism, forming a magnet. The process of a magnet attracting iron is the process of magnetizing the iron block. The magnetized iron block and the magnet's opposite poles generate an attractive force, causing the iron block to firmly adhere to the magnet. We say the magnet has magnetism.