Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of
the compass at the North Pole, so how are the points of the compass
described at the North Pole?

--
Joe
Wolverhampton
175m asl

"Joe Egginton" wrote in message
...
Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of the
compass at the North Pole, so how are the points of the compass described
at the North Pole?


Surely all directions are South... so S,S,S,S If you are directly on the
magnetic pole.

Pharm...

"Joe Egginton" wrote in message
...
Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of the
compass at the North Pole, so how are the points of the compass described
at the North Pole?


Surely all directions are South... so S,S,S,S If you are directly on the
magnetic pole.

Pharm...

"Joe Egginton" wrote in message
...
Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of the
compass at the North Pole, so how are the points of the compass described
at the North Pole?


Surely all directions are South... so S,S,S,S If you are directly on the
magnetic pole.

Pharm...

I hadn't a hope of answering this one myself so I searched Google to see if
someone else could. The following is attributed to a gut called Tom at
http://van.hep.uiuc.edu/van/qa/secti...0505183251.htm

Hope it helps!

Joe

"Good question! I'll assume you are referring to the magnetic poles of the
earth, which are in different locations from the geographic poles. The
geographic poles are defined to be the places where the earth's rotation
axis crosses the surface of the earth, and the magnetic poles are the places
where the magnetic field points straight into or out of the earth's surface.
The magnetic field everywhere is what we call a "vector" quantity. It has a
strength and a direction -- and this direction may point anywhere in
three-dimensional space, including up and down, not just north and south.
Just about anywhere on earth (except near the equator) the field will have
some vertical part to it -- it will be at an angle to the ground.

If you are holding the compass horizontally at one of the magnetic poles, so
that the magnetic field is perpendicular to the plane of the compass, then
there will be no preferred direction for the needle to point. It may point
in the last direction it was pointing as you walked up to the pole. It may
turn until friction slows it down if the needle was spinning (you can get it
spinning by using another magnet or by turning the compass and letting
friction spin the needle up). If you are carrying anything magnetic at the
same time, then the compass needle's direction may point according to this
other object's magnetic field.

If you hold the compass sideways, one end of the compass's needle will point
down into the earth, and the other will point up. If you hold the compass at
some angle between horizontal and sideways (which is most ways of holding
the compass, and it may be hard to get it exactly horizontal), then the
needle will point along the direction which is lowest. Some compasses (the
cheap ones) are built such that the needle is supported on a sharp pin; the
compass needle has a hemispherical cup in the middle and the pin rests in
the cup. The compass needle then may wobble around and dip up and down even
if the compass itself is held flat. It may then dip and point down until the
needle scrapes on the compass face or the needle rubs on the edge of the
cup. More expensive water-filled compasses with special bearings won't
wobble like this and will behave as described above.

Here's a fun experiment to try. See if you can find, with a compass, the
angle the magnetic field makes with respect to the ground in your location.
To do this, you would orient the compass in a variety of different angles
and find the one where the needle does not prefer any direction -- it will
stay anywhere you put it. It might be best to use one of the fancy
water-filled compasses for this, otherwise the pin and cup may rub and
scrape in some orientations more than others and spoil the result. Then the
plane of the compass will be perpendicular to the field. It will be hard to
get it exactly right because if the angles are close but not quite right,
then the magnetic forces on the compass needle will also be very small and
it may take a long time for the needle to swing over to point in the right
direction, and gravity may spoil it if the two ends of the needle weight
different amounts.

Tom

p.s. Just in case you meant what would happen if you stand at the actual
pole (not the magnetic one) the behavior is of course different. At the
north pole, for example, if you hold the compass horizontally the needle
which is supposed to point north will point south, toward the north magnetic
pole. That's not saying much, since at the north pole ANY horizontal
direction is south. The north magnetic pole is somewhere around the islands
in far northwestern Canada, and that's where the needle will point."

"Joe Egginton" wrote in message
...
Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of the
compass at the North Pole, so how are the points of the compass described
at the North Pole?

--
Joe
Wolverhampton
175m asl

I hadn't a hope of answering this one myself so I searched Google to see if
someone else could. The following is attributed to a gut called Tom at
http://van.hep.uiuc.edu/van/qa/secti...0505183251.htm

Hope it helps!

Joe

"Good question! I'll assume you are referring to the magnetic poles of the
earth, which are in different locations from the geographic poles. The
geographic poles are defined to be the places where the earth's rotation
axis crosses the surface of the earth, and the magnetic poles are the places
where the magnetic field points straight into or out of the earth's surface.
The magnetic field everywhere is what we call a "vector" quantity. It has a
strength and a direction -- and this direction may point anywhere in
three-dimensional space, including up and down, not just north and south.
Just about anywhere on earth (except near the equator) the field will have
some vertical part to it -- it will be at an angle to the ground.

If you are holding the compass horizontally at one of the magnetic poles, so
that the magnetic field is perpendicular to the plane of the compass, then
there will be no preferred direction for the needle to point. It may point
in the last direction it was pointing as you walked up to the pole. It may
turn until friction slows it down if the needle was spinning (you can get it
spinning by using another magnet or by turning the compass and letting
friction spin the needle up). If you are carrying anything magnetic at the
same time, then the compass needle's direction may point according to this
other object's magnetic field.

If you hold the compass sideways, one end of the compass's needle will point
down into the earth, and the other will point up. If you hold the compass at
some angle between horizontal and sideways (which is most ways of holding
the compass, and it may be hard to get it exactly horizontal), then the
needle will point along the direction which is lowest. Some compasses (the
cheap ones) are built such that the needle is supported on a sharp pin; the
compass needle has a hemispherical cup in the middle and the pin rests in
the cup. The compass needle then may wobble around and dip up and down even
if the compass itself is held flat. It may then dip and point down until the
needle scrapes on the compass face or the needle rubs on the edge of the
cup. More expensive water-filled compasses with special bearings won't
wobble like this and will behave as described above.

Here's a fun experiment to try. See if you can find, with a compass, the
angle the magnetic field makes with respect to the ground in your location.
To do this, you would orient the compass in a variety of different angles
and find the one where the needle does not prefer any direction -- it will
stay anywhere you put it. It might be best to use one of the fancy
water-filled compasses for this, otherwise the pin and cup may rub and
scrape in some orientations more than others and spoil the result. Then the
plane of the compass will be perpendicular to the field. It will be hard to
get it exactly right because if the angles are close but not quite right,
then the magnetic forces on the compass needle will also be very small and
it may take a long time for the needle to swing over to point in the right
direction, and gravity may spoil it if the two ends of the needle weight
different amounts.

Tom

p.s. Just in case you meant what would happen if you stand at the actual
pole (not the magnetic one) the behavior is of course different. At the
north pole, for example, if you hold the compass horizontally the needle
which is supposed to point north will point south, toward the north magnetic
pole. That's not saying much, since at the north pole ANY horizontal
direction is south. The north magnetic pole is somewhere around the islands
in far northwestern Canada, and that's where the needle will point."

"Joe Egginton" wrote in message
...
Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of the
compass at the North Pole, so how are the points of the compass described
at the North Pole?

--
Joe
Wolverhampton
175m asl

I hadn't a hope of answering this one myself so I searched Google to see if
someone else could. The following is attributed to a gut called Tom at
http://van.hep.uiuc.edu/van/qa/secti...0505183251.htm

Hope it helps!

Joe

"Good question! I'll assume you are referring to the magnetic poles of the
earth, which are in different locations from the geographic poles. The
geographic poles are defined to be the places where the earth's rotation
axis crosses the surface of the earth, and the magnetic poles are the places
where the magnetic field points straight into or out of the earth's surface.
The magnetic field everywhere is what we call a "vector" quantity. It has a
strength and a direction -- and this direction may point anywhere in
three-dimensional space, including up and down, not just north and south.
Just about anywhere on earth (except near the equator) the field will have
some vertical part to it -- it will be at an angle to the ground.

If you are holding the compass horizontally at one of the magnetic poles, so
that the magnetic field is perpendicular to the plane of the compass, then
there will be no preferred direction for the needle to point. It may point
in the last direction it was pointing as you walked up to the pole. It may
turn until friction slows it down if the needle was spinning (you can get it
spinning by using another magnet or by turning the compass and letting
friction spin the needle up). If you are carrying anything magnetic at the
same time, then the compass needle's direction may point according to this
other object's magnetic field.

If you hold the compass sideways, one end of the compass's needle will point
down into the earth, and the other will point up. If you hold the compass at
some angle between horizontal and sideways (which is most ways of holding
the compass, and it may be hard to get it exactly horizontal), then the
needle will point along the direction which is lowest. Some compasses (the
cheap ones) are built such that the needle is supported on a sharp pin; the
compass needle has a hemispherical cup in the middle and the pin rests in
the cup. The compass needle then may wobble around and dip up and down even
if the compass itself is held flat. It may then dip and point down until the
needle scrapes on the compass face or the needle rubs on the edge of the
cup. More expensive water-filled compasses with special bearings won't
wobble like this and will behave as described above.

Here's a fun experiment to try. See if you can find, with a compass, the
angle the magnetic field makes with respect to the ground in your location.
To do this, you would orient the compass in a variety of different angles
and find the one where the needle does not prefer any direction -- it will
stay anywhere you put it. It might be best to use one of the fancy
water-filled compasses for this, otherwise the pin and cup may rub and
scrape in some orientations more than others and spoil the result. Then the
plane of the compass will be perpendicular to the field. It will be hard to
get it exactly right because if the angles are close but not quite right,
then the magnetic forces on the compass needle will also be very small and
it may take a long time for the needle to swing over to point in the right
direction, and gravity may spoil it if the two ends of the needle weight
different amounts.

Tom

p.s. Just in case you meant what would happen if you stand at the actual
pole (not the magnetic one) the behavior is of course different. At the
north pole, for example, if you hold the compass horizontally the needle
which is supposed to point north will point south, toward the north magnetic
pole. That's not saying much, since at the north pole ANY horizontal
direction is south. The north magnetic pole is somewhere around the islands
in far northwestern Canada, and that's where the needle will point."

"Joe Egginton" wrote in message
...
Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of the
compass at the North Pole, so how are the points of the compass described
at the North Pole?

--
Joe
Wolverhampton
175m asl

On Wed, 18 May 2005 21:57:05 +0100, Joe Egginton
wrote:

Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of
the compass at the North Pole, so how are the points of the compass
described at the North Pole?

Within a few degrees of the pole the lines of longitude are used IIRC.

On Wed, 18 May 2005 21:57:05 +0100, Joe Egginton
wrote:

Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of
the compass at the North Pole, so how are the points of the compass
described at the North Pole?

Within a few degrees of the pole the lines of longitude are used IIRC.

On Wed, 18 May 2005 21:57:05 +0100, Joe Egginton
wrote:

Hello All,

At any other point other than the North or South pole, there are four
basic points of the compass N,E,S,W. There are still four points of
the compass at the North Pole, so how are the points of the compass
described at the North Pole?

Within a few degrees of the pole the lines of longitude are used IIRC.