Stefan Bozic Comparing and Contrasting the "Norths" Feb 23, 2013.
While
researching the four types of Norths (True, Geographic, Magnetic, and
Physical), I noticed that several similarities and differences exist between
the four. I found out that Magnetic North holds a whole different set
of properties that does not really relate to the other Norths,
whereas True North and Geographic North are essentially the same. Lastly, I
used the component of common sense to describe the properties of Physical North.
Geographical
North and True North: The
location of the poles for Geographic North is constant, meaning that it is not
affected by the Earth's magnetic field. In terms of the actual direction, it is
based upon the most northern point on the Earth's surface which is located at
90 degrees north of any point on the equator through which the Earth's
rotational axis meets the surface of the Earth. Due to the fact that all
lines of longitude converge at this point and the fact that the Earth's axis
connects both the North and South poles (line in which the earth rotates around
it), Geographic North is also commonly known as True North. In addition, Geographical/True North are
composed of lines of longitude and latitude which begin and end at each of the
Earth's poles, and showcases North and South directions. Another trait that
these two poles share are when one stands at the North Pole, all points are
South of that person since East and West have no bearings. In addition, lines
of longitude have established that since these lines converge at the North
Pole, Coordinated Universal Time (UTC) can be used to determine the time around
the world. Lastly, this principle of the lines
of longitude converging at the North Pole, also explains why the
North Pole (in Geographic and True North terms) has six months of
daylight and six months of darkness. An example of the usage of these
"norths" is on maps published by the Armed Forces, in which True
North and Geographic is represented as five-pointed star. These
"norths" can also be found on TTC Maps, or other regular hiking maps.
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Magnetic North: In literal terms, Magnetic North tends to
shift and move, and refers solely to the pole of the Earth's magnetic field. On
the other hand, it's poles are affected by the magnetic field which is made up
of a molten metallic core (composed mainly of iron). This magnetic field that
causes the poles to move is created by convection and the constant rotation of
the Earth combined with the core of iron. Due to the fact that iron is
magnetic (as it's inner electron shells are unstable), this proves the fact
that the the location of magnetic north refers to the magnetic field.
Therefore, the Magnetic North is determined by the Magnetic Field. Magnetic
North is commonly used alongside compasses, as Magnetic North is located where
the North end of a compass is pointing to. This means that if one were to stand
on the magnetic north pole, the compass would point downward. This happens
because since the same ends of magnets repulse each other, the magnetic
south pole is technically the Earth's Geographic North Pole. In terms of
reality, an example of the usage for the principle of Magnetic North
is a compass, which shows that the exact direction of Magnetic North
varies time to time, because magnetic drift causes the poles to move
every year. And of course, the fluid in the iron acts like a magnet, creating a
weak magnetic field, making the point of "magnetic north" shift
constantly. This is why 100,000 dead fish washed up on the shores of the
Arkansas River last year, as the Magnetic North pole moved.
Physical North: Due to the fact that physical is defined as "of or pertaining to
the body", Physical North then refers to the North in one's perspective.
This may refer to the direction you are facing or the direction in which you
are walking. For example: If one was walking to the mall, the
direction in which they are walking in would be referred to as "Physical
North".
Connections: If you combine both the principles of Geographic/True North and
Magnetic North, it can be seen that a relationship exists between the two since
the Earth's magnet is not aligned with the geographic poles. A difference
exists between these two principles, known as magnetic declination which is
calculated by the angle between Magnetic North and True/Geographic North when both values
are shown on a map. In addition, magnetic declination depends on the place as
the value would be different in Los Angeles (12 degrees East of North) and Australia
(20 degrees East of North). For example: If a cruiser were taking a
trip from Maine (20 degrees West of North) to Florida to Texas (10 degrees
east), the journey would have a True/Geographic North error of 30 degrees if not adjusted
for changing declination. This would result in an error for navigation. Another
example would be the life of a hiker. Since maps are aligned using
True/Geographic North, hikers would have to make adjustments when navigating
with a compass.
APA Citation:
Rosenberg, M. (2010, May 05). About.com. Retrieved February 23, 2013, from
http://geography.about.com/od/learnabouttheearth/a/northpole.html
Rosenburg, M. (2011). About.com. Retrieved February 23, 2013, from
http://geography.about.com/od/learnabouttheearth/a/northpole_2.htm
(2003). Retrieved February 23, 2013, from http://www.wisegeek.com/what-is-the-difference-between-the-
north-pole-and-magnetic-north-pole.htm
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