Image description

The image shows the evolution of the protection system for tall objects on the ground, from electric shock by lightning.

Thus, the image on the left shows the experiment of the American inventor Benjamin Franklin raising a kite to height during a storm, and which is struck by lightning, and the image on the right shows a lightning rod fixed on the roof of a tall building.

In both images there is at the top, a cloud rendered by dotted texture, under which a lightning discharges, rendered by a broken or jagged line, vertical and embossed.

In both images the ground below is rendered by a checkered texture, blank rhombuses alternating with embossed rhombuses.

On June 10, 1752, Benjamin Franklin and his son William, try to demonstrate the electrical nature of lightning, raising a kite during a storm. While the kite is struck by lightning, it collects an electric charge in a Leyden jar, a device that stores electricity. The kite was tied with a metal wire and a metal key, which in turn was tied to a silk ribbon. When the silk ribbon began to rise in the air, he was warned that the lightning would be discharged as soon as possible.

Thus, the electric current was discharged both in the jar and in the inventor’s body.

The raised kite flies under the cloud and is rendered by a rhombus, a square inclined and elongated at the top and bottom tips, embossed, cut in the center by a blank cross.

The metal wire on which the kite is attached is marked with a curved line, in the central part, which forks, one part to the lower right, towards the jar, and one part to the lower left, towards the man.

The lower right key is rendered by a small embossed circle, joined down by a short line with two teeth.

The jar on the ground, lower right, and the man holding the thread with which he rises the kite, left, are highlighted embossed.

Lightning rod is a system that intercepts the atmospheric electric discharge and safely conducts it to earth.

It consists of the following parts:

  • lightning rod, rendered by a thickened vertical line, located above the building, top right.
  • conductive roof support, to which the rod is fixed and further connected to the copper wire.
  • the conductive material, usually made of copper, through which the discharged electric current flows and whose path descends on the roof slope and then along the wall, all the way to the ground. The copper wire is rendered by a thickened line, parallel to the right side of the building.
  • ground rod, fixed in the soil, under the building, at the bottom edge, rendered by an elongated rectangle, vertical and embossed.

The building is marked by a vertical embossed rectangle, above which stands a triangle with the top up, also embossed, representing the roof.

General information

From the multitude of phenomena of nature, lightning is encountered, less often or more frequently, in almost all areas of our planet. By the time science explained its formation, lightning was seen as the storm god or the god of weapons. In some faiths, lightning was regarded as a life-giving god, but also as a vengeful god, who kills on the spot those who do not obey the divine commandments.

Based on the research, scientists have determined that lightning is electrical discharges that form bright arches. These discharges can occur inside a single storm cloud, but also between several clouds that have opposite electrical charges. Clouds can be charged positively or negatively. During lightning, the air is suddenly heated to over ten thousand degrees Celsius. Due to rapid heating, the air expands, and an explosion occurs that we call thunder. Thunder is heard by the late man, not when the lightning strikes. The delay is due to the difference in the speed of propagation between light and sound. The net propagates at about three hundred and thirty meters per second, and the light propagates millions of times faster than the sound.

If lightning is electrical discharges between clouds with opposite electrical charges, lightning is electrical discharges that occur in a cloud and earth. We distinguish two main types of lightning: negative lightning and positive lightning. Negative lightning is most common and occurs between the base of the cloud and the earth. The positive one is between the top of the cloud and the earth. The positive lightning has a much higher energy than the negative one and is also called lightning from the clear sky, because it can strike several kilometers from the site of production.

Knowing how lightning formed, it was possible to invent the protection instrument against its effects, namely the lightning rod. It can be used both to protect buildings and to protect open spaces. By protecting open spaces, you can avoid the occurrence of vegetation fires causing you lightning.

The lightning rod consists of three main parts: the capture device that is the highest part of the lightning rod, the descent conductors through which lightning energy passes, and the earthing sockets.

The working principle of the lightning rod is simple. It captures the lightning energy and deviates it from the point of view of protection, to the earth’s crust. In short, the lightning rod is grounding, a protection against electric shock. The lightning rod must be installed in the highest place of the lens to be protected.

Did you know that lightning was the discovery of fire by man? Those who lived long before us couldn’t use fire in a controlled way, so they couldn’t light it when they needed it. Instead, the fire was lit from time to time by a lightning bolt, and people used it as long as it burned.

The place on earth where most lightning strikes occur is Lake Maracaibo in Venezuela. This is where there’s lightning per hour.


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  2. http://www.avizepram.ro/paratrasnet-activ-paratrasnet-pasiv/
  3. https://ro.wikipedia.org/wiki/Paratr%C4%83snet
  4. https://ro.wikipedia.org/wiki/Tr%C4%83snet
  5. https://adevarul.ro/locale/alba-iulia/cum-formeaza-fulgerul-trasnetul-tunetul-fenomenul-periculos-om-
  6. https://ro.wikipedia.org/wiki/Tr%C4%83snet

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