Compasses work on the principle of magnetism with the earth as a giant magnet having a magnetic field running between the North and South Poles. Make a simple magnetic compass with a needle and water to demonstrate this magnetic function. Rub a magnet over a metal needle several times along the vertical from eye to tip to magnetize it. Poke it through a thin slice of cork and float it in a bowl of water. Use an actual compass to check that the magnetized needle is accurately pointing north.
In a pinch, an analog watch can act as a compass to find general directions on a sunny day. Set the watch to standard time for the time zone you are in and hold it flat in your hand. Point the hour hand toward the sun. Find the halfway point at the shortest distance between 12 and the hour hand to locate south. North will be directly opposite, east to the right and west to the left on the horizontal plane.
The best way to master direction finding with a compass is repeated hands-on practice. You can turn this practice into a game and add an element of fun to the learning. Hide a treasure, such as candy, or set up a class picnic at a secret location. Gather the class at a nearby location and give them compass directions such as, "Walk 200 feet on a southwest bearing. Turn 90 degrees to the north and walk 50 feet." Each student will first need to measure the length of one pace based on the length of his legs in order to calculate correct distance measurements. When students reach the prize location, celebrate with a class party or snacks.
Orienteering is a timed race using a map and compass to navigate through a series of checkpoints in unfamiliar terrain. At each checkpoint, you find the directions to the next. Orienteering clubs hold meets with levels for beginners, intermediate and advanced compass users. Alternately, you can set up your own course in a park, school yard or field.
Geocaching and letterboxing are high tech treasure hunts using GPS devices and compasses to find hidden "caches." People hide containers in secret locations around the world containing logbooks to sign or stamp. A geocache holds trinkets to trade while letterboxers stamp logbooks with personalized stamps to mark their finds. The idea is that the geocacher will leave a "treasure" in return for the trinket taken to keep the cache supplied for future seekers. It is important to re-hide the box in the same location and condition in which you found it to maintain the game for those who come after you. To start searching for a cache near you, search the databases at the Geocaching or Letterboxing North America websites.