Most substances are composed of molecules, which are made up of atoms, and atoms consist of atomic nuclei and electrons. Inside an atom, electrons constantly rotate and orbit around the atomic nucleus. Both of these movements produce magnetism. However, in most substances, the directions of electron movement are different and disordered, with their magnetic effects canceling each other out. Therefore, most substances do not exhibit magnetism under normal conditions.

Iron, cobalt, nickel, or ferrite, among other ferromagnetic materials, differ in that their internal electrons 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 magnetism, forming a magnet. The process of a magnet attracting iron is the same as magnetizing the iron block, where the magnetized iron block and the magnet's opposite poles generate an attractive force, causing the iron block to firmly stick to the magnet. We then say that the magnet has magnetism.