For my whole life I assumed that the north pole was called the north pole because when looking at the map, the needle pointing north is facing in the direction of the north pole. I never questioned if this was the truth or not, I just went along with it like a foolish young child. However, on Thursday, February 23, 2012, the truth was exposed to my innocent mind.
First, let's think of the earth as being a magnet or having a magnet buried inside. (1) In the centre, the core is made out of iron, and as it moves, it creates an electric current that causes a magnetic field around the earth. A compass needle is actually a tiny magnet, with the north end painted red. In order for the north end of the compass to point to the North Pole, you have to assume that the "magnet" in earth has to have the south end at the North Pole. So in actuality, the North Pole is the South Pole! It is called the North Pole because it is near the top of the earth, or geographic north, however, it is really a magnetic "south" pole. This is why a compass needle's north end points to it.
This is due to the fact that opposite charges attract each other. Therefore, that would cause the north end of the compass needle to point toward the south end of the buried magnet. So the compass would point towards the North Pole. However, these poles are not quite lined up with the geographic North Pole and South Pole shown on a map, because the moving inner core's poles are constantly wandering around.
In reality, the bar magnet does not run exactly the earth's rotational axis. It is slightly bent to the side. Using a compass in the north can give you problems. The needle is actually pointing at the magnetic pole, which is not directly at the geographic pole. Now, in general most people use a GPS to determine their desired location, which does not rely on the position of "true north" but rather on satellites.
It is only at the equator that the field is parallel to the earth's surface. The angle between the earth's surface and the magnetic field is called the angle of inclination.
Earth's magnetic field lines also attract particles from outer space. As particles stream down through the atmosphere towards the magnetic poles, they cause the northern lights. (3)
(1) Earth's Magnetic Field. (n.d.). Retrieved from http://adventure.howstuffworks.com/outdoor-activities/hiking/compass1.htm
(2) Earth's Inconstant Magnetic Field. (2003, December 29). Retrieved from http://science.nasa.gov/science-news/science-at-nasa/2003/29dec_magneticfield/
(3) How Does The Aurora Borealis (The Northern Lights) Work?. (n.d.). Retrieved from http://science.howstuffworks.com/nature/climate-weather/atmospheric/question471.htm
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