Quick Answer
To build a natural compass using a stick and shadow, insert a straight stick into the ground at an angle, mark the end of the shadow with a small rock, wait for 30 minutes, and mark the new end of the shadow. Repeat this process, and the midpoint of the two marks will indicate south. This method is based on the Earth's slightly flattened shape and the resulting variation in the angle of the sun's shadow.
Understanding the Method
The method of building a natural compass using a stick and shadow takes advantage of the Earth’s slightly flattened shape. The sun appears to be slightly north of the true south because the Earth is slightly flattened at the poles. This means that the shadow of an object will be longer in the south than in the north at the same time of day.
Creating the Compass
To create the compass, insert a straight stick into the ground at an angle. Mark the end of the shadow with a small rock, taking note of the time. Wait for 30 minutes and mark the new end of the shadow with another small rock. Repeat this process two or three times, allowing the sun to move to a different position. The midpoint of the two marks will indicate south, while the midpoint of the second and third marks will indicate north.
Refining Your Compass
To refine your compass, you can use the direction of the sun at different times of day to estimate your position. For example, at sunrise, the sun is in the east, and at sunset, it is in the west. By combining this information with the compass, you can estimate your latitude and longitude. However, this method requires a good understanding of astronomy and should be used only as a last resort in a survival situation.
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