Once you understand how spins and domains create magnetic fields, everyday technology starts to look completely different. A loudspeaker, for example, works because a magnet interacts with a coil of wire. When an electric current flows through the coil, it produces a changing magnetic field. This new field pushes and pulls on the permanent magnet inside the speaker. A thin membrane connected to the coil vibrates, and these vibrations become sound waves.

Electric motors use a similar idea. Inside a motor, magnets and coils interact to create continuous rotation. The electric current constantly shifts the magnetic field of the coils, which pushes against the fixed magnetic field of the permanent magnets. Because electrons in the magnets are already aligned, their magnetic order provides a stable force that the motor can push against.

Magnetism also stores information. In a computer hard drive, tiny domains are aligned in different directions to represent digital bits — the zeros and ones that make up every image, video, or program. Even the compass in a smartphone depends on magnetism. The Earth itself acts like a giant magnet, and small magnetic sensors can detect its field to determine direction.

Modern technology would not exist without the quiet cooperation of electrons. Whether they vibrate in a speaker, rotate in a motor, or store data in a memory device, their spins and their ability to form ordered domains shape the world we use every day.