UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
Why do electrons only spin two different ways? What prevents them from spinning in other directions?
Answer 1:

To begin with, subatomic particles such as electrons do not spin in the same way as the Earth spins on its axis. Spin is a quantum state that causes electrons and other particles to exhibit properties as if they were spinning, such as possessing a magnetic dipole moment (because electrons are charged), as well as a few other things. Symmetry with other subatomic particles demands that electrons have only two spin states, which are +1/2 and -1/2. This essential pairing of electron states is fundamental to chemistry; it is why, for example, the electron shells of atoms all have multiples of two electrons, but otherwise have room for the square of the number of valence shells from the nucleus (i.e. 2 = 2x1, 8 = 2x22 = 2x4, 18 = 2x32 = 2x9, etc.). However, there is no preferred direction to how electrons rotate as if they were genuinely rotating particles; spin is different from that.

Answer 2:

Electron "spin" can be in any direction.It's only when you place electrons in a magnetic field that the spins tend to line up either parallel to the field or opposed to it.

Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2015 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use