Particle Behaviour

**gonegahgah** · Nov7-09, 07:01 PM

I trust your word Bob so I accept that what you say is the scientific position.
I must admit I find it challenging to believe that it is possible to affect anything without some form of attraction or repel but I'll have to live with it I guess.

At the macroscopic level I could have a free moving ring of ball bearings.
If I point a common tree stick at it nothing will happen.
If I wave or move the stick at or around it nothing will happen still; unless I made contact.
The ball bearings are just not attracted to the stick.
However it is different if I move a magnet over the ball bearings.
If I point a magnet at one part of the ring nothing will happen.
However, if I move the magnet above the ring in a circular motion following the ring I will induce movement of the ball bearings in the same direction.

So at the macro level we require some form of attraction to induce movement.
This is why I admit I am surprised that there is no attraction required at the nanoscopic level to induce movement of electrons.
Must be one of those things where things don't happen at the quantum level the same way they do at our level, hey?

**Bob S** · Nov7-09, 07:55 PM

Originally Posted by gonegahgah

.
However, if I move the magnet above the ring in a circular motion following the ring I will induce movement of the ball bearings in the same direction.

What you are describing here is conceptually similar to a polyphase induction motor. The stator coils produce a rotating magnetic field that induces currents in the copper rotor squirrel cage until the rotor reaches the synchronous frequency of the stator field.
[Added] There are also variable (slotted rotor) reluctance synchronous motors that have laminated rotors with axial slots running along the outside surface. These rotors speed up until they phase lock with the stator's rotating field.

Bob S

**gonegahgah** · Nov8-09, 05:31 PM

By sheer co-incidence I read the following in the book "Quantum" by Manjit Kumar:

"In classical physics, angular momentum, everyday spin, can point in any direction. What Uhlenbeck was proposing was quantum spin - 'two valued spin', spin 'up' or spin 'down'. He pictured these two possible spin states as an electron spinning either clockwise or anticlockwise about a vertical axis as it orbits the atomic nucleus. As it did so, the electron would generate its own magnetic field and act like a subatomic bar magnet. The electron can line up either in the same direction or the opposite direction as an external magnetic field. Initially it was believed that any allowed electron orbit could accommodate a pair of electrons provided that one had spin 'up' and the other had spin 'down'. However these two spin directions have very similar but not identical energies, resulting in the two slightly different energy levels that gave rise to the alkali double lines - two closely spaced lines in the spectra instead of one."

Does the reference to magnetic fields bear any relevance to what we are discussing or is it an idea that was later supplanted - I haven't finished the book yet; the book does seem to be about the evolution of our understanding?

**Bob S** · Nov8-09, 05:46 PM

Originally Posted by gonegahgah

Does the reference to magnetic fields bear any relevance to what we are discussing or is it an idea that was later supplanted - I haven't finished the book yet; the book does seem to be about the evolution of our understanding?

No relevance. Learn about electric motors. If you are interested in permanent magnet rotors in electric motors, read about brushless permanent magnet dc (BLDC) motors in
http://oretano.iele-ab.uclm.es/~mhid...entos_BLDC.pdf
I think you should learn a little electrical engineering before you complete your education in quantum mechanics.
Bob S