Quick Answer
Create a vertical stick shadow on a flat surface, wait for a short time, and draw a line where the tip of the shadow is. Then, create another vertical stick shadow at the same location, wait for the same amount of time, and draw a line where the tip of the new shadow is. The midpoint of these two lines is approximately south.
Creating the Shadow Stick
To determine direction using a shadow stick, find a stick about the length of your arm and a flat surface with no obstructions. Place the stick on the ground vertically and note where the tip of the shadow is. Wait for a short time, about 15-30 minutes, depending on the time of day and location. Mark the end of the shadow with a small rock or stick. Repeat the process by creating another vertical stick shadow at the same location, but this time wait for the same amount of time as before. Mark the end of the new shadow with a small rock or stick.
Plotting the Direction
Now that you have two marks on the ground, draw a line between them. The midpoint of these two lines is approximately south. This method is called the “gnomon method” and relies on the fact that the Earth rotates from east to west, causing the sun’s shadow to move accordingly. By waiting for the same amount of time and creating two marks, you can estimate the direction of south.
Tips and Variations
To increase the accuracy of the gnomon method, wait for the same amount of time each day at the same location, and create multiple marks to get a more precise reading. You can also use a watch or a phone to estimate the time, but it’s essential to be aware that the shadow stick method may not work well in areas with heavy tree cover or during periods of heavy cloud cover.
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