Why do the magnetic compass always show north?

A large magnetic field exists near the top of the earth. This pulls the needles of compass in the same direction.

For a detailed answer, check this site out -->

http://starryskies.com/Artshtml/dln/8-97/compass.h...

Hope that helps!

Scouts and sailors can tell you how important compasses are. Day or night, rain or shine, a compass will always show you where north is, or will it? Does a compass always point north? What does it do at the north or south pole? I was recently asked the following question on this subject.

"Recently some sailors sailed in the South Pole region of the Earth. I would like to know what reading their compass showed as they sailed South to get as close to the pole as possible. What would happen if they left their ship and hiked overland to the magnetic south pole?"

Hold a compass in your hand and it will point to the Earth's north pole. Why? Because the Earth is like one giant magnet and the compass points to the magnetic north pole. In fact, even if you go south of the equator and quite close to the south pole, the compass will still point to the north magnetic pole. With only two exceptions, it will always behave that way. But first, you might wonder why the Earth behaves like a magnet at all.

To best understand Earth's magnetic field, picture a bar magnet and a bunch of iron filings dumped around it. The filings form lines running from the north pole of the magnet to the south pole of the magnet. We call these lines magnetic field lines. The compass is acting somewhat like the iron filings and is pointing towards the north pole. The actual cause of the magnetism has to do with the interior of the Earth.

We know that at the center of the Earth lies a molten metallic iron rich core. The outer portion of this core is molten. We also believe that this core is spinning. Our knowledge of the details of exactly what causes the magnetic field is sketchy but it is believed that the metals in the core have many loosely bound electrons and that these particles can conduct electricity. It is this mass of moving electrons which produces the magnetic field.

So now we know what causes the magnetism that attracts the compass. The sailors mentioned above also saw their compass pointing to magnetic north even though they were as far south as Antarctica. And we know that the compass nearly always points to magnetic north. So what are those two exceptions? If you were to take a compass and stand just over either the north or the south magnetic pole, you would see the compass spin freely. From the south pole, every direction is north and from the north pole, there is no north. But there is still a way you could know where you were!

The kind of compass we usually think of is a standard compass -- held horizontally -- its needle is only free to move around to the left or the right. A different sort of compass, called a "dip compass," has a needle that moves in the vertical direction, rather than in the horizontal. From magnetic south, its needle would point straight up into the sky -- because at the south magnetic pole, the magnetic field emerges straight up out of the ground. At the north pole, the opposite end would point up.

Our earth displayes a magnetic field and this field is practically the same as a large magnet.

The north pole is actually the south portion of a magnet and the south pole is actually the north.

All magnets will line up to fit into the field of the earth, thats how compasses work.

Magnets exhibit the field going out of the north into the south so the earths field goes from the south pole to the north so compasses and magets floating on foam in water will line up this way.

It is because of magnetic fields. Magnetics have north and south poles, and opposite poles attract. The earth is large enough that it has its own magnetic field. Ironically, the south pole of the Earth is at geographic north (so at the top of a map) while the north pole is at geographic south (and the bottom of a map). Compasses have a little magnetic bar that swings around to show you north. The north (top) end of the magnet swings towards the south pole (top) of the earth. Therefore, magnetics always show north. :)

In physics, all magnets have two poles that are distinguished by the direction of the magnetic flux. In principle these poles could be labelled in any way; for example, as "+" and "−", or "A" and "B". However, based on the early use of magnets in compasses they were named the "north pole" ("N") and the "south pole" ("S"), with the north pole being the pole that pointed north. When it was later understood that opposite poles attract, a terminological dilemma arose: the Earth's North Magnetic Pole and the pole of the magnet that was attracted to it could not have the same polarity. By convention, the "north pole" of a magnet remained defined as the one attracted to the Earth's North Magnetic Pole,[1][2] and by this definition the Earth's North Magnetic Pole is physically a magnetic south pole.[3] Conversely, the Earth's South Magnetic Pole is physically a magnetic north pole.

Because of the Magnetic field that the earth has. If you are at the very north, or very south of the earth your compass will not work!!!

you may be knowing that earth has a magnetic field.in any magnet the magnetic current conventionally is to go from south to north .when a magnetic object is kept in this field .it tries to be in a position so that to give the minimum resistance to the magnetic field .it is experimentally found that when the a object Aline it self to the magnetic field the resistance is less.so the magnet bar in compass Aline with the magnetic field of the earth

so it shows north..........

many of the other answers are right except you can't say "always" here because if you are standing on the north magnetic pole the compass does not want to point north.....it wants to point "down". If not allowed to do that there is just no telling which way it will be pointing.

Because of the Earths magnetic field.

Answer is simple .It is because earths(as a magnet) South pole is towards the geographical north.