In the XVIII century, the inquisitive human mind got to the study of such phenomena as: electricity and magnetism. An outstanding American researcher and well-known politician, one of the authors of the American Constitution, Benjamin Franklin, who enthusiastically studied charged particles, was the first to draw attention to the similarity of the nature of atmospheric electricity and electricity produced in the process of friction. The next logical conclusion made by the great scientist was his theory about the electrical nature of the occurrence of lightning. In parallel, in the course of his numerous experiments, Franklin was one of the first to reveal the electrical properties of conductors having a pointed shape. It was them that he proposed to use to prevent direct lightning strikes into tall buildings and to destroy the electric charge in thunderclouds. So Benjamin Franklin came up with a lightning rod - an invention that mankind uses everywhere to this day.

The device mounted by Dalibar was a pointed vertical iron spike, 40 feet high, mounted on a non-conductive wooden stand. Soon, during a severe thunderstorm on March 10, 1752, the first scattering of sparks 4-5 centimeters long were recorded on the conductor. The structure erected by Dalibar was not yet a lightning rod in the modern sense, but already served as proof that it was possible to “catch” and reduce atmospheric electricity to the ground. Having repeated the experience before Ludwig XV, Thomas-Francois Dalibard received a lifetime cash pension.

In the summer of 1752, Franklin conducts another of his famous experiments with flying a kite under the clouds. His attempt with the help of a kite to collect an electric charge and transfer atmospheric electricity along a metal cord from a kite to the surface of the earth was successful and finally confirmed the scientist in the idea that the properties of atmospheric electricity are similar to the properties of electricity obtained on earth.

In September 1752, Franklin installed a 9-foot pointed iron rod on the roof of his house in Philadelphia and connected it to the well with 7 mm iron wire. The scientist led the wire through the room, installing an electric bell on it, which was supposed to come into action when lightning hits the lightning rod. This research device became the first prototype of the modern grounded. Soon, lightning rods became widespread in America, and by 1783 there were more than 400 of them in Philadelphia alone. By the way, lightning still struck Franklin's house many years later (in 1786), without causing any harm to the building, which gave the scientist opportunity to see your lightning rod in action.

In Europe, Franklin's invention initially met with fierce resistance from conservative scientists and religious leaders, but over time, the feasibility of installing lightning rods was proven in practice.

Franklin's outstanding abilities as a politician, diplomat, writer, scientist, naturalist and researcher of social processes were highly appreciated by his contemporaries and are recognized by posterity. As a mark of respect for his contributions to science and society, a portrait of Benjamin Franklin has been invariably featured on the $100 bill in the United States since 1914, an honor normally only bestowed on the President of the United States.

Lightning rod: how does it work?

In this age of soaring cities, there is no need to discuss the question "what is the purpose of a lightning rod." Every schoolchild knows that objects rising above the ground fall into an increased risk zone during a thunderstorm. It is more interesting to find out: how the lightning rod works.

The principle of operation of a classic lightning rod is based on the property of a grounded metal object to intercept lightning heading towards the ground. The lightning rod consists of three main parts:

• Moniepriemnik - a metal pin or wire, the purpose of which is to receive a lightning strike;
• Down conductor - a metal conductor (wire) designed to send current from the lightning rod to the ground electrode;
• Grounding conductor - metal rods, wire, tape, piles, reinforcement of the reinforced concrete foundation of the building, etc., whose task is to distribute the lightning current in the ground.

Currently, the search for ways to protect against lightning continues. Scientists are looking for new ways to protect property and people's lives. Lightning rods based on radioactive elements, the so-called "active lightning rods", lightning rods using a laser beam, and even structures that prevent the development and, accordingly, a lightning strike, have been developed and are being improved. The enthusiasm of scientists makes us believe that we will soon forget about fires after a thunderstorm.

But each of these new devices has a problem. Radioactive lightning rods turned out to be too dangerous for humans due to the radiation released during operation. "Active lightning rods", as well as lightning rods that prevent the occurrence of a lightning discharge, do not have scientific confirmation, which means that their use is in deep doubt. Laser lightning rods could not come out from behind the walls of laboratories and exist only in the form of experimental installations.

A paradoxical situation has arisen. In the modern world, despite the riot of technology, lightning rods based on the principles developed by Benjamin Franklin remain the most effective and optimal in terms of the sum of functional, consumer and operational qualities. This means that metal rods installed on the roof of the house, conductors laid along the walls and pins in the ground combined into a single system are still the best choice for lightning protection!

Despite so far failed attempts to create a super-lightning rod, in the last 30 years, it has become possible to deal not with a direct lightning strike, but with its consequences. For example, with step voltage easily depriving a person of life, with lightning discharges sliding over the surface of the earth, setting fire to ammunition depots, with lightning current drifting into the building through wires, ruthlessly putting out of action expensive electrical appliances and complex production equipment. The long-term work of the scientific community has not been in vain. The rules for creating lightning rods were clarified, time-tested. Today, designers have in their hands regulatory documents and computer programs that allow creating lightning protection with the highest reliability!

Today, almost all public buildings that are potentially threatened by lightning are equipped with protective equipment in the form of. Being inside the building during a thunderstorm, we can not be afraid for our lives.

Thus, the greatest invention of Benjamin Franklin, made by him in the 18th century, became the basis for the fight against one of the greatest fears - the fear of the powerful destructive power of the heavenly elements.

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