Most substances are composed of molecules, which are made up of atoms, and atoms consist of an atomic nucleus and electrons. Within an atom, electrons spin and orbit around the atomic nucleus. Both of these movements produce 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 conditions.

Iron, cobalt, nickel, or ferrite and other ferromagnetic materials differ in that the electrons within them can spontaneously align within a small range, forming a spontaneously magnetized region, which is referred to as a magnetic domain.

After magnetization, ferromagnetic materials have their magnetic domains neatly aligned and oriented, enhancing their magnetic properties, thus 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 attract each other, causing the iron block to firmly adhere to the magnet. We say that the magnet has magnetism.