Using a Compass
How The Earth's Magnetic Field Affects a Compass
The magnetic field exerts a force on charged objects. The compass needle is charged, so the fields exerts a force on it. The magnetic field of the earth, is aligned in such a way, that one pole is at the north pole and that the other is at the south. Thus the earth's magnetic field, pushes the compass needle so that it points in the direction of north.
How a Compass Works
Necessarily a compass is a light weight magnet, normally a magnetized needle, on a rotating pivot. This allows the needle to better react to nearby magnetic fields. Since opposites attract the southern pole of the needle is attracted to the Earth's natural magnetic north pole.
Labeled Diagram of the Earth's Magnetic Field
The field is the strongest near the poles and weakest near the equator. In addition, the field lines at each location on the Earth intersect at the Earth's surface at a specific angle of inclination. Near the equator, the field lines are parallel to Earth's surface; the inclination angle there is said to be 0 degrees.
How To Use a Compass:
Step 1
a) Place the compass on the map so that the long edge connects the starting point with the desired destination.
b) Make sure the direction arrows are pointing from the starting point to the place of destination.
c) By now, you will want to use the scales on your compass to determine the distance you need to travel.
Step 2
a) Hold the compass firm on the map in order to keep the base steady.
b) Turn the rotating capsule until the North-South on the bottom f the capsule are parallel with the North-South line on the map.
Step 3
a) Hold the compass in your hand in front of you. Make sure that the direction arrows are pointing straight ahead.
b) Rotate your body until the North-South arrow on the bottom of the capsule lines up with the magnetic needle, and the red end of the needle points in the same direction as the arrow.
c) The directional arrow on the base plate now shows your desired travel direction.
Compass 101 - How to Use a Baseplate Compass