Magnetism does not begin at the surface of a metal but in the smallest building blocks of its atoms. Each atom contains electrons that move around the nucleus, and every electron has a property called spin. You can imagine spin as a tiny directional arrow, like a microscopic compass needle. In most materials these arrows point in many different directions. One arrow may point up, another down, another sideways, and because their directions cancel one another out, the material shows no magnetic behavior.

Certain metals, such as iron, nickel and cobalt, behave differently. Their electrons can group together into small regions where many spins point in the same direction. These regions are called domains. A single domain already behaves like a tiny magnet with its own north and south pole. However, in an ordinary piece of metal the domains are arranged randomly, each pointing its own way. Because they do not reinforce one another, the metal does not act as a magnet.

Magnetism appears only when a large number of these domains become aligned. When their spins point in a shared direction, the small magnetic effects add up to create a strong, unified force. What we feel as magnetism is therefore nothing more than the visible result of millions of electrons quietly forming order inside a metal.