What is, really, the spin of an electron?

Question

(sorry for my english)

Hi everyone,

Earlier today, i was studying the electronic distribution of atoms and it was all going fine until it got to the part about spin. My textbook presented spin as if it was just a fact, with no causes or consequences, which is weird, since my physics teacher always tells us to try to contextualize phenomena so, i decided to do some research into why electrons spin, and it consequences.

I’ve spent pretty much the whole day trying to understand what causes the electron to spin, and what arises from it, but I still couldn’t find a satisfactory answer. At first, I read that the spin of electrons create the magnetic field of an atom, but then another page told me that it has little do with it. Then, there’s a whole thing that they don’t actually spin at all, which confused me even further.

To be frank I’m completely lost in the matter, and I would appreciate any direction as to Why and How the electron spins, and if the spin is what creates the magnetic field or not.

Thanks,

Terec

In: Physics

Answer 1

I think the issue with spin is that it sounds like the emergent spinning-motion that we associate with a spinning top or something. There is a good reason why it’s called spin though.

In practice, I think its best to think about spin the same way to think about mass and charge. What exactly is mass? What exactly is charge? Its just intrinsic fundamental properties that things can have. Even though its quite hard to reduce them even further, we are pretty okay with talking about the mass and charge or a particle. The same should apply to spin.

Another way of thinking about spin is to just replace it with the words ‘angular momentum’, because that’s spin really is. Particles can have mass, momentum, charge, angular momentum, and there are some conservation laws/symmetries associated with those properties. Spin is part of angular momentum.

The fact that electrons don’t actually spin like a spinning top shouldn’t distract from the idea that spin is just another fundamental property of a particle. The reason why the picture is wrong is the same reason why the particle picture of an electron in an atom is wrong: the quantum mechanical wavefunction isn’t a particle.

Hopefully this helps to resolve some tension. I know it can be an unsatisfying answer, but I think it removes a lot of unnecessary confusion.