# The Naked Scientists Forum

### Author Topic: A prophet crying ...............  (Read 3037 times)

#### McQueen

• Hero Member
• Posts: 545
• Thanked: 6 times
##### A prophet crying ...............
« on: 18/07/2005 22:41:59 »
I am not  a prophet calling out in the wilderness  ,   more like the little boy standing on the side of the road and pointing out that the Emperor isn’t wearing any clothes , if anything . I will make three statements which are widely accepted.
1)   A stationary charge (electron ) gives rise to a static electric field.
2)   A charge moving with uniform velocity results in a magnetic field.
3)   An accelerating charge gives rise to an electromagnetic field.
These  three seeming aphorisms , which underpin most of the present understanding of electrodynamics , turn out on closer examination to be bland and misleading  For instance if one were to take a bar magnet , it is possible to see that the magnetic “lines of force “ are generally accepted to flow from the  south to north poles through the magnet and from the north to the south poles through the air, forming loops which pass through the body of the magnet and continue through the air. If this same magnet were to be bent into a horse shoe shape , the lines of force  re-arrange themselves to form concentric rings perpendicular to the body of the magnet but can still be seen to flow through the magnet in a south pole to north pole direction and through the air in a  north pole to south pole direction thus forming a complete circle , part of which is through the air and part of which is through the magnet. Finally if the straight bar magnet is bent into a complete circle , the only “lines of force” seen outside the magnet are in the form of concentric rings  around the body of the magnet .  The magnetism due to a current and that due to a permanent magnet are identical and are both attributed to moving  electric charges. However , in the case of a current , the moving charges are electrons which are physically moving through the wire , while in the case of  permanent magnetism the charges are electrons which are spinning as well as orbiting the nucleus of the atom. This difference in the origin of the magnetism in each case  is why  the two fields are supposedly different. A straight  bar magnet has magnetic fields which form loops running through and around it , while a straight wire has magnetic fields which are in the form of concentric rings perpendicular to the wire. It can be seen that the magnetic field around a circular magnet and the magnetic field around a straight wire are identical. Yet what is  not acknowledged is that the straight wire is actually part of a circular current. Is this a coincidence? Does  the fact that the field around a  circular  wire and that around a circular  magnet are identical have any significance , doesn’t it , at least to a certain extent , negate the claim that the field around an incorrectly named straight  wire is due to the electrons flowing through it ?   Further the impression that is deliberately  fostered is that these concentric lines of force around a wire carrying a current are merely hanging in space around the wire and that they are due to the movement of electrons within the wire in the form of a projected field. Yet if the same wire is laid horizontal and iron filings are used to trace the field , it is found that the iron filings are now concentrated on the wire itself ( the same holds true in the case of a circular magnet ).The significance of the iron filings attaching themselves to the wire is that lines of force are flowing through the wire at every point. The  conclusion has to be  that the lines of force are flowing through and around the wire or the magnet and not just hovering in space . Yet this fact is never  cited.

#### gsmollin

• Hero Member
• Posts: 749
##### Re: A prophet crying ...............
« Reply #1 on: 19/07/2005 04:38:34 »
quote:
Originally posted by McQueen
...The  conclusion has to be  that the lines of force are flowing through and around the wire or the magnet and not just hovering in space . Yet this fact is never  cited.

Not true. It is well known that there is a magnetic field inside the wire. Wherever there is a current density, there will be a magnetic field produced. It does not matter if the current is confined to a conductor, or is diffuse, within a space.There are many treatments of the internal magnetic field within a conductor. I calculate these fields myself as a routine part of performing my job.

The major difference between the magnetic field produced by a current, and a permanent magnet, is that the permanent magnet's field depends upon spin-moments of electrons becoming aligned within the magnet. The electronic current in a wire is produced by conduction band electrons that have random spin-moments.

#### The Naked Scientists Forum

##### Re: A prophet crying ...............
« Reply #1 on: 19/07/2005 04:38:34 »