How Do Magnets Work?

A magnet is one of the first pieces of real physics most of us ever hold. Slide one across a table towards another and you feel it — an invisible push or pull, with nothing touching, no string, no trick. It is genuinely strange when you stop to think about it. So how does a lump of metal reach out across empty space and grab another? The answer takes us deep inside the atom, and reveals one of the most important connections in all of science. This guide explains how magnets work.

What it is

Magnetism is a force, produced by the movement and spin of electrons inside atoms, that causes certain materials to attract or repel one another without touching. Everything is built from atoms, and within every atom are electrons — tiny, electrically charged particles. As these electrons move and spin, each one behaves like an unimaginably small magnet.

In most substances, these tiny atomic magnets point in every direction at random, so their effects cancel out and the material shows no magnetism. In a magnet, something different has happened: vast numbers of these electrons line up in the same direction, so their individual contributions add together. The combined result is strong enough to feel — and that is magnetism.

Magnetic poles

Every magnet, no matter its size, has two ends with opposite character, called poles: a north pole and a south pole. They cannot be separated. Snap a bar magnet in half and you do not get one north piece and one south piece; you get two smaller magnets, each with its own north and south. This pairing is fundamental to how magnetism works.

The poles govern the behaviour everyone knows from playing with magnets:

• Opposite poles attract. Bring a north pole near a south pole and they pull together.
• Like poles repel. Bring two north poles, or two south poles, together and they push apart.

This simple rule — opposites attract, likes repel — is the heart of magnetic interaction, and it falls directly out of how the magnets' fields meet, which we turn to next.

The magnetic field

A magnet does not need to touch something to affect it, because it is surrounded by an invisible region called a magnetic field. This is the area around a magnet within which its force can be felt; the closer you are, the stronger it is.

You can actually see the shape of this field. Scatter iron filings on paper over a bar magnet and they arrange themselves into curved lines arcing from one pole to the other. These field lines map the field's direction and strength: where they crowd together, near the poles, the field is strongest.

A magnetic field is not empty space being mysterious. It is a real, measurable region of influence, and it is what lets one magnet act on another across a gap.

Understanding the world through such careful observation and measurement is exactly the approach described in the scientific method — turning an everyday wonder into something we can map and predict.

Why iron is magnetic

Only a handful of materials make good magnets or are strongly attracted to them — chiefly iron, along with nickel and cobalt. The reason lies in how their atoms can organise.

In these metals, groups of atoms naturally form tiny regions called domains, within which all the electrons line up the same way. Each domain is itself a small magnet. In an ordinary, unmagnetised piece of iron, the domains point in random directions and cancel out. But expose the iron to a strong magnetic field, and the domains swing into alignment, all pointing the same way. Now the whole object behaves as a magnet.

This also explains some familiar effects. Stroke a steel needle with a magnet and you can magnetise it by aligning its domains. Drop or heat a magnet hard enough and you can scramble those domains again, weakening or destroying its magnetism. Most materials — wood, plastic, glass, water — simply cannot form aligned domains at all, which is why they ignore magnets entirely.

The deep link with electricity

Here is the most profound part. Magnetism is not a force on its own; it is one half of a single, unified force called electromagnetism. Magnetism and electricity are intimately connected, each able to create the other.

• Electricity creates magnetism. Pass an electric current through a wire and a magnetic field appears around it. Coil the wire and add an iron core, and you build an electromagnet — a magnet you can switch on and off, used in everything from scrapyard cranes to doorbells.
• Magnetism creates electricity. Move a magnet near a coil of wire and it pushes the electrons in the wire along, creating an electric current. This single discovery is the basis of nearly all the world's power generation.

This two-way relationship is why so much of modern life runs on electromagnetism, and why understanding electricity and magnetism really means understanding one phenomenon, not two. The same connection lies behind motors, generators and even the broader family of electromagnetic waves that includes the light responsible for rainbows.

The Earth is a magnet

On the grandest scale, our entire planet behaves like a giant magnet. Deep in the Earth's core, the movement of molten iron generates a vast magnetic field that surrounds the whole world. This is what makes a compass needle swing to point north, and it shields us from much of the harmful radiation streaming from the Sun.

The same churning interior that drives this magnetic field is bound up with the heat and motion deep underground that also shifts the tectonic plates at the surface — a reminder that the planet's hidden depths shape our world in more ways than one.

The bottom line

Magnets work because of electrons — the movement and spin of these tiny charged particles inside atoms makes each a minute magnet, and in a true magnet, countless electrons line up to act as one. Every magnet has a north and a south pole, with opposites attracting and likes repelling, and each is wrapped in an invisible magnetic field that lets it act across empty space. Materials like iron are magnetic because their atoms can align into domains, while most materials cannot. Above all, magnetism is inseparable from electricity: two faces of a single force that powers the modern world and even surrounds our planet.