North vs. South

crutschow

Joined Mar 14, 2008
24,722
You would think that is true, but Physics.Org disagrees. http://www.physics.org/article-questions.asp?id=65 For the red on most compasses to be a North poled magnet on the pointer, it would need to be of South polarity.
Nope.
You misread the Physics.org article.
It agrees with what I said.
The north (seeking) pole of a magnet (compass) points north.
The earth's magnetic north pole is, of course, a south (seeking) pole.
 

MrAl

Joined Jun 17, 2014
7,490
Nope.
You misread the Physics.org article.
It agrees with what I said.
The north (seeking) pole of a magnet (compass) points north.
The earth's magnetic north pole is, of course, a south (seeking) pole.
You are both right!
But the convention is that we call the magnet end that *points* to earths north pole "north".
But it could not do that if the earth north pole was really a magnet north pole.
The correct wording for the magnet north pole is actually "north seeking pole" which makes reference to a geographical location not a magnetic pole as we would have with another magnet.
 

shortbus

Joined Sep 30, 2009
7,600
You are both right!
But the convention is that we call the magnet end that *points* to earths north pole "north".
But it could not do that if the earth north pole was really a magnet north pole.
The correct wording for the magnet north pole is actually "north seeking pole" which makes reference to a geographical location not a magnetic pole as we would have with another magnet.
Now that is confusing.
The way I read it I would think that @crutschow and Physics.Org are in agreement.
But that also makes the red or north seeking point of a compass a south pole of a magnet. Like poles repel, unlike poles attract. So if the red end of the pointer was actually "north magnetically(permanent magnet)" it would need to point south.
 

MrChips

Joined Oct 2, 2009
20,884
Let's get this straight.

1) North and South are arbitrary names.
2) The North geographic pole is accepted as the one nearest to the Arctic Circle.
3) The end of the compass that points to geographic North is declared to be a north magnetic pole, i.e. it is the geographic North seeking pole.
4) Therefore the Earth's south magnetic pole is located in the vicinity of the Earth's geographic North.
 

MrAl

Joined Jun 17, 2014
7,490
Let's get this straight.

1) North and South are arbitrary names.
2) The North geographic pole is accepted as the one nearest to the Arctic Circle.
3) The end of the compass that points to geographic North is declared to be a north magnetic pole, i.e. it is the geographic North seeking pole.
4) Therefore the Earth's south magnetic pole is located in the vicinity of the Earth's geographic North.
Hi,

Yeah i was trying to get that point across. There's no ambiguity there either it's clearly defined and this will appear all around the web and in text books. The key phrase is "North Seeking Pole" which means the end that points to the earths north location is called the north pole of the magnet. That magnet pole is never called the south pole even though it could have been called that a long time ago perhaps.
 

MrAl

Joined Jun 17, 2014
7,490
But that also makes the red or north seeking point of a compass a south pole of a magnet. Like poles repel, unlike poles attract. So if the red end of the pointer was actually "north magnetically(permanent magnet)" it would need to point south.
See Mr Chips post after yours.
It's an issue like conventional current flow. It's an accepted standard to call the end that points to geographic north the north pole regardless what we call the earth magnetic polarity.

In the distant future this may change if the earths magnetic polarity shifts again. But for now it is relatively stable.
 

shortbus

Joined Sep 30, 2009
7,600
Let's get this straight.

1) North and South are arbitrary names.
2) The North geographic pole is accepted as the one nearest to the Arctic Circle.
3) The end of the compass that points to geographic North is declared to be a north magnetic pole, i.e. it is the geographic North seeking pole.
4) Therefore the Earth's south magnetic pole is located in the vicinity of the Earth's geographic North.
All of that is fine, but that isn't what is taught or wasn't taught in school. Most people would think what I've been saying, if they understand how a compass works at all, the the red end of the pointer is a south pole.
 

BR-549

Joined Sep 22, 2013
4,938
A compass is a magnet with two ends. The end that pointed N was referred as the N pointing pole, later just N pole..........long before any study.

The N pole was named for the north direction.......and they kept it. We kept it for a reference direction for M flux, for the lefthanded generator rule and the right handed motor rule.

These rules has been used for decades to relate M flux direction......to current direction.

So, as related to current(charge and electricity), the earth's N geographic pole is a S pole of the earth's magnetic dipole.
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,138
Man plans while God laughs, near as I can tell the poles or on the sides of these .125" diameter cylinders that are 0.25" long.. I plan on using these little magnets to latch a 3D printed box closed,using mutual attraction and repulsion to orient the two halves of the 3D printed boxes. Nothing dictates the poles are on the ends of these little cylinders other than a personal bias. Even though it is inconvenient I'll pick one end and call it north. After all, I should have a 50/50% chance of being partially right.

Insert cuss words here.
 

MrChips

Joined Oct 2, 2009
20,884
What do you mean that the poles are on the ends of a cylindrical bar?
The poles are everywhere!

Here is a test. Take a cylindrical bar magnet and break it in half (just a thought experiment).
Do you end up with a north pole in one hand and a south pole in the other?
Guess what? You end up with two bar magnets, each with its own north and south poles!
 

BR-549

Joined Sep 22, 2013
4,938
The magnetism is always there, because the charge is always there, it just isn't normally lined up, for our benefit.

Every piece of matter is a magnet.
 

MrAl

Joined Jun 17, 2014
7,490
What do you mean that the poles are on the ends of a cylindrical bar?
The poles are everywhere!

Here is a test. Take a cylindrical bar magnet and break it in half (just a thought experiment).
Do you end up with a north pole in one hand and a south pole in the other?
Guess what? You end up with two bar magnets, each with its own north and south poles!
But what if you dont break it? :)
 

MrChips

Joined Oct 2, 2009
20,884
As @BR-549 stated, every matter is a potential magnet.

A ferromagnetic material consists of tiny magnets called magnetic domains.

When the material exhibits no magnetic field, all the domains are oriented in a random fashion. When subjected to a magnetic field, domains will tend to align along the applied field, collectively becoming a magnet itself. When the domains remain in their aligned orientation after the external field is removed, the material becomes a permanent magnet.

If you break a permanent magnet into fragments, each fragment is in itself a magnet.

 

Thread Starter

Wendy

Joined Mar 24, 2008
22,138
Monopoles have only recently been shown to exist in nature though they were theoretically possible before, with lots of extra rules governing them. Several threads are floating around in this Forum. Even more articles on the web. A quirk of quantum physics. Worth Googling. However, Monopoles are off topic for this thread. Either start a new thread or chat about them on an existing thread.
 

BR-549

Joined Sep 22, 2013
4,938
A magnetic field is half of existence for anything physical. The other half is an electric field.

Your body is half magnetic and half electric. You are charge.
 
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