Re: Magnetic Polarity Re: Magnetic quenching.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "Daniel Ullfig" <DUllfig-at-sbcglobal-dot-net>
 >
 >  >     The definition of North Magnetic Pole is That Which Points Geographic
 >  >     North.  Period.
 >  >
 >  >     THIS means that the Earth's Geographic North Pole is associated with
 >  >     a SOUTH magnetic polarity there (actually: Northern Canada, or the
 >  >     nearby ice pack...  8)>>)
 >  >
 >  >     yes: it is counterintuitive and mind bending.  Also true..
 >  >     Had it cross checked by a physicist once.  For experimental
 >  >     verification:
 >  >     Wind a solenoid, observing 'left hand' rule for winding direction,
 >  >     connect DC PSU in Specified Polarity and check compass...
 >
 > The concept of north and south poles is completely arbitrary; Physicists
 > could have started by saying "the earth is a giant magnet, and the north
 > pole coincides with the magnetic north pole". then we would have decided
 > that the south pole of a magnet is that which points to the north; finaly,
 > when we discovered that electricity produces a magnetic field, we would have
 > discovered the "right hand rule" instead of the "left hand rule", and it
 > would all have worked out anyways. In physics, some rules are just
 > arbitrary, and everyone agrees to them.
 >
 > Dan

	It was common in the older books to refer to the "north-seeking pole"
of a compass needle, which is not ambiguous.  Of course, this is the
south pole of the needle.  I wonder if the original designation of north
came about because most navigation was done in the northern hemisphere
where Polaris was commonly observed to indicate north?

Ed