eli5 How do permanent magnets work?

Question

I know any moving charges / electric current create a magnetic field, and this is what creates magnetic effects in electromagnets. But how do the exact same effects appear in permanent magnets? And where does the energy come from? tia

In: 5

Answer 1

Ferromagnetic materials are a pretty complicated story because the effect starts all the way down at the quantum properties of electrons, but can only be amplified up to be relevant at macroscopic scales in certain conditions. My favourite explanation is [this one, from minutephysics and Veritasium](https://www.youtube.com/watch?v=hFAOXdXZ5TM)

> And where does the energy come from?

That’s the thing that can be a bit tricky to wrap your head around – permanent magnets *do no work*, and therefore do not consume energy.
This is true of other bodies that generate fields too. When you use muscle force to ascend a diving tower, that’s you doing work to move to a place in Earth’s gravitational field with higher potential energy. The kinetic energy you gain when you jump off the dive tower is exactly the same as the potential energy difference between your mass at the top of the tower and at the surface of the water.
The Earth hasn’t spent energy accelerating you towards the water, you’re just getting back as speed the energy you spent climbing the tower (not including losses like your muscles releasing heat, which didn’t increase your potential energy).