>>11204212>>11205932>It doesn't actually spin, but it was a good analogy for an observed property, so scientists called it "spin".It's normal spin around an axis, but it's not good to picture the particle as extended, it's a spinning point.
There is no qualitative difference between an elementary particle spin and the angular momentum of a molecule, or even a baseball, except that it's usually smaller for a particle, and the elementary particle spin can be fundamentally half-integer, while orbital dynamics spin is always integer.
The two things are described by the exact same mathematical thing, the angular momentum states of quantum mechanics and their superpositions, and these have the same classical limit--- the spinning top--- which is the limit of large amount of angular momentum. The only difference is that the number of quanta of angular momentum an elementary particle has is usually small, and so it is not usually near the classical limit. The other difference is that you are not supposed to imagine the angular momentum as coming from constituent motion of parts.
But aside from that, it is angular momentum, exactly like a spinning top. It transfers to material objects. So if you have electrons on a wire, and you reverse their spin with a magnetic field, the wire will twist a little to get the twice the electronic angular momentum in a macroscopic motion. This is the famous Einstein deHaas experiment.
There is no difference between fundamental particle spin and top spin, except for size, and occasionally half-integer quantum number.
>but the spin doesn't come from the constituent motion of its parts!It's a spinning point. What else would you expect from a spinning point? No parts, spinning. It's not even weird.
