Physics Question #3813
Ben, a 17 year old male from the Internet asks on March 8, 2007,
What exactly are Proton Spin Numbers, and how can you have a non-integer proton spin number?
viewed 13666 times
answered on March 8, 2007
Protons, electrons and most other particles have intrinsic spin, a form of built in angular momentum (just like it sounds). But "fermions", a class of particles that includes protons and electrons, have spin that is one half of Planck's quantum of angular momentum, and this property is connected with several other differences between fermions and bosons (particles with integer spin). One of these is the Pauli Exclusion Principle, which says no two fermions can be in the same state in the same place at the same time -- in contrast to bosons, which (like idiots everywhere) love to be in the same state!
If that answer is far more complicated and confusing than you wanted or expected, join the club. Except for a few "natural philosophers", most physics students look upon this division of particles into half-integer-spin fermions and integer- (or zero-) spin bosons as a fact of nature that we can't "explain" but simply have to "get used to".
Add to or comment on this answer using the form below.
Note: All submissions are moderated prior to posting.
If you found this answer useful, please consider making a small donation to science.ca.