Fire means survival.
by tonytran2015 (Melbourne, Australia).
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#make fire, #making fire, #fire, #Sun, #sunlight, #crystal, #glass #ball, #sphere, #lens, #ocular, #monocular #sun-rays, #survival.
You may already have in your possession some excellent lenses for making fires. Knowing about them will help you make fire quickly from sunlight when facing an emergency. All lenses described in this blog can make a cigarette smoulder in less than 30 seconds and can light up that cigarette afterwards.
1. Concentration of radiating heat flux by a lens.
The radiating heat flux from the Sun is concentrated by a factor C given by
C = Pi*d*d/(Pi*f*a*f*a) =
C = (d/f)*(d/f)*(1/a)*(1/a).
where d and f are respectively the diameter and focal length of the lenses and a is the angular diameter of the…
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