Discover how your thumb can serve as a reliable and precise measuring tool for survival!
By following the visual line from the eye to the thumb, then from the thumb to the object, we can deduce the approximate distance. This technique, although rudimentary, can prove crucial in a survival context, where every detail counts to navigate and locate oneself precisely in nature.
This technique is really precise and allows you to measure any distance simply:
- Hold your thumb in front of you (arm fully extended) and close one eye. Align your thumb with an object that you have an idea of the size of (for example, a car).
- Without moving your thumb, close the open eye and open the other. Your thumb then seems to be in another place.
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The car is approximately 15 feet long. Converting to meters, this is approximately 4.57 meters (because 1 foot is 0.3048 meters).
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If your thumb covered half the length of the car, that's about 7.5 feet, or about 2.29 meters (7.5 feet x 0.3048 = 2.286 meters).
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Multiplying this estimated distance by 10 gives you the estimated distance between you and the car. So, 2.29 meters multiplied by 10 equals approximately 22.9 meters.
Too good to be true ? I walked around and tried it. I also brought a laser range finder and a tape measure to check. I immediately noticed that I was tempted to measure the space between the two images of my thumb, when instead I should measure from the left side of the first image of the thumb to the left side of the second thumb image.
Standing in the kitchen, watching the television in the other room, I estimated that the television was between 36 and 48 inches wide and that my thumb moved a little more than half that distance, or about 61 cm. Calculation: The television should be approximately 6.1 meters away. The laser level indicates: 7.62 meters. Okay, it's not bad.
From my desk to a nearby shelf, my thumb moved six inches, maybe a little more. Calculation: approximately 152 cm. Actual measurement: 150 cm.
From a spot on my driveway to a shed: I turned my head and side to measure relative to the height of the door. The thumb distance should be approximately 183 cm, so the garden shed should be approximately 18.29 meters away. Actual measurement: approximately 1.5 meters. It's not perfect, but again, it's not too far off.
The reason this trick is supposed to work is because the distance between the eye and the thumb is about 10 times the distance between one eye and the other. I also measured it. Looking in the mirror with a tape measure in front of my face, my pupils are 5.84 cm apart. The distance from the point between my eyebrows to my outstretched thumb is 59.69 cm. This represents a factor of 10.2.
Also discover our multifunction map which will allow you to find your way easily and which will not take up any space in your bag!