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 spontaneously magnetized area known as a magnetic domain.

After magnetization, ferromagnetic materials have their magnetic domains neatly arranged in a uniform direction, which strengthens the magnetism and forms a magnet. The process of a magnet attracting iron is the process of magnetizing the iron block. The magnetized iron block and the magnet attract each other due to opposite poles, and the iron block sticks firmly to the magnet. We say that the magnet has magnetism.