Inspection of things from a tourist backpack
If someone present nearby wore glasses, then the lens from them could be used as a magnifying glass, and with its help, set fire to paper, then wood chips, dry birch bark, and then branches. Then it would be possible to finally warm up by the fire, and cook food on its fire.
What can be used instead of a lens? When going on a hike, a tourist will definitely take a spoon. Here is the replacement, at least in form. And if it’s a shiny spoon made of chromium-nickel steel, then it’s also based on its ability to collect sunlight.
True, the curvature of the spoon is uneven: it is greater in the transverse direction and less in the longitudinal direction. To make the curvature uniform, bend it a little along the length and straighten it across the width.
The degree of flexion and extension can be controlled by the reflection of your face in the spoon. When it becomes approximately uniform in any position of the spoon, the goal can be considered achieved. Such a modified spoon will more or less collect the rays of the sun into one point (focus), i.e., concentrate them.
Now we need a material like tinder, which would have the property of easily igniting. It can also be found among the things that a tourist will certainly take with him when going on a hike. We mean a roll of toilet paper, it is better to use a piece of black or dark fabric.
As you know, a black surface absorbs heat to a greater extent than a white one. We will need a seasoned tourist pot, or rather, the soot from its bottom - the standard black color, and this is what we need. Now we have everything to start making fire.
Getting fire from the sun using a spoon
Polish the surface of the spoon until it shines. This can be done with any matter.
We start by making tinder from toilet paper. We tear off a piece from it sufficient to twist a dense rod with a diameter of about 4 mm, rolling it several times between the palms in the same direction.
Then we prepare one side of the resulting toilet paper rod for ignition, or rather, to obtain a smoldering red coal. To do this, tear off the tip to form a slightly fluffy end.
In order for the tip of the paper wick to better perceive thermal energy, we apply a little soot from a camp pot to it. Now not a single quantum of thermal energy that falls on the blackened tip of our improvised tinder will be wasted.
Then we take the already modernized spoon and orient the scoop perpendicular to the sun’s rays.This will allow you to concentrate the maximum amount of thermal energy at one point.
Next, we place the tip of the soot-blackened toilet paper tinder at the focus of our makeshift lens and hold both objects motionless until the tinder ignites and a stable red ember is formed.
There is no need to be afraid that the fire will go out: once toilet paper or fabric catches fire, it will not burn, but will smolder, and for a long time and steadily.
You can use dry grass for ignition.
Let's inflate.
It turned out to be fire.
Final notes and tips
You can avoid damaging the spoon by bending it, but then the process of igniting the tinder will be longer and more difficult. After all, the double curvature of the spoon will form two foci with less thermal energy in each.
Any concave surface is suitable for igniting a fire: a watch lid, a curved lid from a tin can, the bottom of a glass bottle, or, finally, a lens cut out of ice. Instead of toilet paper, you can use a cigarette, dry moss, birch bark or a piece of black fabric.
