Creating Your Own Compass

If you don't have a compass, you can create your own in much the same way people did hundreds of years ago. To create your own compass, you will need the following materials:

  • A needle or some other wire-like piece of steel (a straightened paper clip, for example)
  • Something small that floats such as a piece of cork, the bottom of a Styrofoam coffee cup, a piece of plastic or the cap from a milk jug
  • A dish, preferably a pie plate, 9 to 12 inches (23 - 30 cm) in diameter, with about an inch (2.5 cm) of water in it
The first step is to turn the needle into a magnet. The easiest way to do this is with another magnet -- stroke the magnet along the needle 10 or 20 times as shown below.

magnatizing a needle to make your own compass

If you are having trouble finding a magnet around the house, two possible sources include a can opener and an electromagnet that you make yourself (see How Electromagnets Work).

Place your float in the middle of your dish of water as shown below.

making a simple compass

The "float on water" technique is an easy way to create a nearly frictionless bearing. Center your magnetic needle on the float. It very slowly will point toward north. You have created a compass!

Gyroscopic Compasses
A magnetic compass like the one created above has several problems when used on moving platforms like ships and airplanes. It must be level, and it tends to correct itself rather slowly when the platform turns. Because of this tendency, most ships and airplanes use gyroscopic compasses instead.

A spinning gyroscope, if supported in a gimbaled frame and spun up, will maintain the direction it is pointing toward even if the frame moves or rotates. In a gyrocompass, this tendency is used to emulate a magnetic compass. At the start of the trip, the axis of the gyrocompass is pointed toward north using a magnetic compass as a reference. A motor inside the gyrocompass keeps the gyroscope spinning, so the gyrocompass will continue pointing toward north and will adjust itself swiftly and accurately even if the boat is in rough seas or the plane hits turbulence. Periodically, the gyrocompass is checked against the magnetic compass to correct any error it might pick up.

For more information on compasses, navigation and related topics, check out the links on the next page.