Magnetic Theory
The usefulness of electricity is greatly expanded through magnetism. Magnetism enables the existence of electric motors, generators, coils, relays, solenoid, transformers, etc. Magnetism, like electricity, can't be seen, weighed on a scale or measured with a ruler. How it works and is put it to use can be understood.
Two theories exist to explain how magnets work. The first theory states that a large quantity of small magnetized particles exist in a magnet. If the item is not magnetized the particles are arranged in a random order. When the item becomes magnetized the particles align with each other.
The second theory states that when the electrons of atoms are arranged in a certain order, the circles of force of each atom combine creating the magnetism.