How a hiking compass works

A hiking compass is an important instrument for hiking, camping and other outdoor activities. A hiking compass’s size is always as: 45mm(dia) x 10mm(H), With a key ring, which enable it to be carried easily and play as a hang decoration. Well do you know how a hiking compass works.
   
The hiking compass is an instrument to identify location. The predecessor of compass is one of the China’s four great inventions called Sina. The main part is a magnetic needle in the shaft that can twirl freely.

A compass functions as a pointer to "magnetic north" because the magnetized needle at its heart aligns itself with the lines of the Earth's magnetic field. The magnetic field exerts a torque on the needle, pulling one end or pole of the needle toward the Earth's North magnetic pole, and the other toward the South magnetic pole. The needle is mounted on a low-friction pivot point, in better compasses a jewel bearing, so it can turn easily. When the compass is held level, the needle turns until, after a few seconds to allow oscillations to die out, one end points toward the North magnetic pole.

A magnet or compass needle's "north" pole is defined as the one which is attracted to the North magnetic pole of the Earth, which is actually the south pole of the Earth. The compass needle's north pole is always marked in some way: with a distinctive color, luminous paint, or an arrowhead.

Since the Earth's magnetic poles are near, but are not at the same locations as its geographic poles, a compass does not point to true north. The direction a compass points is called magnetic north, the direction of the North magnetic pole. Depending on where the compass is located on the surface of the Earth the angle between true north and magnetic north, called magnetic declination can vary widely, increasing the farther one is from the prime meridian of the Earth's magnetic field. The local magnetic declination is given on most maps, to allow the map to be oriented with a compass parallel to true north.