Topics Physics and everyday science

How do magnets work?

A magnet works because of moving electric charge. Every electron in an atom acts like a tiny magnet, partly because of a property called spin. In most materials those tiny magnets point every which way and cancel out. In a magnet, such as iron, a large share of them line up, and their small pulls add into a field you can feel across a gap.

What makes this interesting is how much hides behind something so ordinary. Magnetism and electricity turn out to be two faces of one force, which is why a wire carrying current can act like a magnet and a moving magnet can push current through a wire. There is also a fair question about why the pull exists at all. Physics describes it with great precision, but at the bottom it says this is how the universe behaves.

An episode would start with the fridge magnet and work down: fields, poles, why iron sticks and wood doesn't, and why cutting a magnet in half never gives you a lone north pole. The hosts at bre are AI, so they can slip up, and you can press Talk to ask them to slow down or try a different picture.

What a bre episode would cover

An outline of the episode bre would make for this question. Every episode is written fresh when you ask, so yours will differ.

  1. What a magnetic field actually isThe invisible region around a magnet where other magnets and some metals feel a force. Iron filings on paper make the shape visible.
  2. Electrons as tiny magnetsMoving charge makes magnetism, and electrons carry a property called spin that behaves like a small magnet. Most atoms cancel these out.
  3. Why iron sticks and wood doesn'tIn iron, nearby atoms line up in small regions called domains. Wood has no such alignment, so there is nothing for a magnet to grab.
  4. Why poles always come in pairsCut a bar magnet in two and you get two smaller magnets, each with a north and a south. Nobody has found a single isolated pole.
  5. Electricity and magnetism are linkedA current makes a magnetic field and a changing field pushes current. That link powers electric motors and generators.
  6. How a magnet gets made, and unmadeAligning domains with a strong field creates a magnet. Heat or hard knocks can scramble them and weaken it.
  7. What we still can't sayPhysics predicts magnetism extremely well, yet why nature has these forces at all is not something it answers.

How the episode might open

A sample exchange between two of bre’s AI hosts, bre and Arlo. Both are AI; this is written by AI, as every bre episode is.

  1. breAI host

    Okay, picture a magnet on your fridge. Nothing is touching the door except one flat face, and still it holds up a school photo and a pizza menu. What is actually holding them?

  2. ArloAI host

    A field. Invisible, yeah. Sounds like a cop-out to me.

  3. breAI host

    Fair. So let's make it less spooky. A field just means that at every point around the magnet, a force would act on something placed there. It is a map of pushes and pulls.

  4. ArloAI host

    Fine. But where does the push come from?

  5. breAI host

    From electrons. Each one is like a tiny magnet, and in iron a lot of them line up the same way, so their small pulls add together instead of cancelling.

  6. ArloAI host

    Lining up. That's the whole trick?

  7. breAI host

    Mostly, yes. Alignment is the trick. The harder question is why iron lines up and copper doesn't, and I'd rather get to that honestly than hand-wave it.

  8. ArloAI host

    Good. Hand-waving I can't stand. Go on.

Questions people also ask

Why do magnets attract some metals and not others?
Iron, nickel and cobalt have atoms whose electron spins can line up in groups, so they respond strongly to a magnet. Metals like copper and aluminum don't form those groups, so a magnet barely affects them. Many everyday metals are weakly magnetic at most.
Can you have a magnet with only one pole?
Not so far. Every magnet ever found has both a north and a south pole, and cutting one in half just makes two smaller magnets. Some theories predict single poles, called monopoles, but none has been observed.
Why do magnets lose their strength?
Heating a magnet or hitting it hard can knock its aligned atomic regions out of order, weakening it. Above a certain temperature, different for each material, iron stops being magnetic at all. Strong opposing magnetic fields can also scramble the alignment.
Is magnetism the same as electricity?
They are two aspects of one force, called electromagnetism. Moving electric charge creates a magnetic field, and a changing magnetic field can drive an electric current. They are not identical, but you can't fully separate one from the other.

Related topics

More: all 300 topics, physics and everyday science, or the longer reads on /learn.

bre’s hosts are AI, and every episode is generated, so they can be wrong: check anything that matters. This page outlines what an episode would cover. It is for interest and learning, not medical, financial or legal advice.