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Re: [Phys-L] problems with the physics regents



On 6/14/2012 5:38 AM, Chuck Britton wrote:
This is STILL very confusing terminology.
I haven't heard the 'North Pointing' label used in several decades.

I decided to hang a bar magnet in the classroom to clear things up.

There are WAY more bar magnets and compass needles in the world than there are worlds - so - the majority wins.
As Paula Abdul tells us - Opposites Attract - so the earth's magnetic pole up where Santa Claus lives must be the South one.

But - so far - there really aren't ANY magnetic (mono) poles anyway. The Right Hand Rule - rules.

.
At 9:23 PM -0500 6/13/12, brian whatcott wrote:

Ah, woe is me: I thought that the North-pointing end of the magnetic needle
points to the Magnetic north pole.

Once upon a time (as all the best fairy stories start...)

...there was a Chinese mariner with a sampan rigged junk who adopted a direction finder superior
to the direction-pointing trailer (it worked at sea, not just land) It consisted of a lode-stone on a silk suspension.
He knew it was called a lode stone because it pointed to the Lode Star. To help him remember that direction,
he had one end colored appropriately.

Then, when Europeans adopted that cunning device, they noticed something strange: it did not ALWAYS
point to the Lode Star, but sometimes deviated East, sometimes West.

They concluded that the device did not really point to the lode-star - nearly fixed in the Heavens, but
instead pointed to another sky position, which wandered slightly from year to year.
On a terrestrial globe, they would mark the north and south pole as fixed - by convention north up - and marked
the magnetic pole with a dot which they showed wondering from year to year.
They called this the Magnetic north pole to distinguish it from the terrestrial north pole.

And everyone lived happy ever after, until a new kind of natural philosopher came along.
They were fond of finding cases where their insight was somehow superior to those mariners with tar
on their hands and heels, and this time they asserted that the north magnetic pole is not really near
the north pole, it's near the south pole.

So any mariner in earshot nodded wisely, and said, "You must be right, you are a natural philosopher."
....And once out of earshot determined among themselves to continue the long and largely satisfactory
practice of marking northerly headings as (N) or (T) as the case might be.

And that's all the story I have time for, today. :-)

Brian W