So You're Trying to Use a Compass..

A informative PSA about compasses.

I have my compass, now how do I use it?

Unlike a GPS, a compass does not allow you to pinpoint your exact location, instead: it is an instrument containing a magnetized pointer that shows the direction of magnetic north and bearings from it (Merriam-Webster Online: Dictionary and Thesaurus). In order to use a compass you have to follow a series of steps:

1. Gather the materials needed: a compass, map, and pencil or marker.

2. Make marks. On the map, make a mark of your location, and where you want to go

3. Next, take the edge of the compass, draw a line from where you are to where you would like to go.

4. Once you've done this, hold the compass in front of your chest and let the red point travel towards the North.

5. Finally, use the map to figure out what direction you need to walk towards.

Diagram of a Compass

Baseplate: A hard, flat surface on which the rest of the compass is mounted.

Scales: Each edge of a compass has a different ruler and different map scales.

Direction-of-Travel Arrow: Point this the way you will be traveling.

Magnifier: Allows you to see smaller map features

Index Pointer: Very end of the direction-of-travel arrow.

Dial: Ring around the housing that has degree markings engraved into it.

Declination Marks: Used to orient the compass in an area with known Declination.

Orienting Arrow: Marked on the floor of the housing. It rotates with the housing when the dial is turned. You use it to orient a compass to a map.

Needle: Magnetized piece of metal that has one end painted red, this is to show which way is North. It will move freely when the compass is held level and steady.

Housing: This is the main part of the compass. It's a round plastic container filled with liquid, inside is the red needle.

*Note: Not every compass will have all of the things listed above.

How Does It Work?

The only reason you can use a compass is because of Earth's Magnetic Field, and that thing is huge. The needle inside of the Housing aligns with this enormous magnetic field, and as seen in the picture to the left, the composition of Earth acts as a huge bar magnet sitting upside down smack dab in the middle of the planet. Since its South end is at the north pole and its North end is at the south pole, the North end of a compass needle is always pulled towards the north. Your compass has to have a very light needle sitting on a pivot that has almost no friction, this is because the Earth's Magnetic Field is weak and would not be able to turn the needle itself.

Diagram of the Earth's Magnetic Field

Big image

If You Still Have Questions...

How to Use a Compass & Map [Compass Navigation Tutorial]
Compass 101 - How to Use a Baseplate Compass