Plants are energized by the planet's electric field. How plants react to electricity. Device for stimulating plant growth

Soil electrification and harvest

In order to increase the productivity of agricultural plants, humanity has been turning to soil for a long time. The fact that electricity can increase the fertility of the top arable layer of the earth, that is, enhance its ability to form big harvest, the experiments of scientists and practitioners have long been proven. But how to do this better, how to link soil electrification with existing technologies for its cultivation? These are the problems that have not been fully resolved even now. At the same time, we must not forget that soil is a biological object. And with inept intervention in this established organism, especially such a powerful means as electricity, you can cause irreparable damage to it.

When electrifying the soil, they see, first of all, a way to influence the root system of plants. To date, a lot of data has been accumulated showing that a weak electric current passed through the soil stimulates growth processes in plants. But is this the result of the direct action of electricity on the root system, and through it, on the entire plant, or the result of physicochemical changes in the soil? Leningrad scientists took a certain step towards understanding the problem.

The experiments they carried out were very sophisticated, because they had to find out a deeply hidden truth. They took small polyethylene tube-chambers with holes into which corn seedlings were planted. The tubes were filled with a nutrient solution containing a complete set of necessary substances for the seedlings. chemical elements. And through it, using chemically inert platinum electrodes, a direct electric current of 5-7 μA/sq was passed. cm. The volume of solution in the chambers was maintained at the same level by adding distilled water. Air, which the roots desperately need, was systematically supplied (in the form of bubbles) from a special gas chamber. The composition of the nutrient solution was continuously monitored by sensors of one or another element - ion-selective electrodes. And based on the recorded changes, they concluded what and in what quantity was absorbed by the roots. All other channels for the leakage of chemical elements were blocked. In parallel, a control version worked, in which everything was absolutely the same, with the exception of one thing - no electric current was passed through the solution. And what?

Less than 3 hours had passed since the start of the experiment, and the difference between the control and electric variants had already emerged. In the latter, nutrients were more actively absorbed by the roots. But perhaps the problem is not in the roots, but in the ions, which, under the influence of an external current, began to move faster in the solution? To answer this question, one of the experiments involved measuring the biopotentials of seedlings and at certain times included growth hormones in the “work”. Why? Yes, because without any additional electrical stimulation they change the activity of ion absorption by roots and the bioelectrical characteristics of plants.

At the end of the experiment, the authors made the following conclusions: “Passing a weak electric current through the nutrient solution in which the root system of corn seedlings is immersed has a stimulating effect on the plants’ absorption of potassium ions and nitrate nitrogen from the nutrient solution.” So, does electricity still stimulate the activity of the root system? But how, through what mechanisms? To be completely convincing of the root effect of electricity, they conducted another experiment, in which there was also a nutrient solution, there were roots, now of cucumbers, and the biopotentials were also measured. And in this experiment, the functioning of the root system improved with electrical stimulation. However, it is still far from unraveling the ways of its action, although it is already known that electric current has both direct and indirect effects on the plant, the degree of influence of which is determined by a number of factors.

Meanwhile, research into the effectiveness of soil electrification expanded and deepened. Today, they are usually carried out in greenhouses or in growing experiments. This is understandable, since this is the only way to avoid mistakes that are unwittingly made when experiments were carried out in field conditions, in which it is impossible to establish control over each individual factor.

Very detailed experiments with soil electrification were once carried out in Leningrad by researcher V. A. Shustov. He added 30% humus and 10% sand to slightly podzolic loamy soil and through this mass, perpendicular to the root system, between two steel or carbon electrodes (the latter performed better) passed an industrial frequency current with a density of 0.5 mA/sq. cm. The radish harvest increased by 40-50%. But direct current of the same density reduced the collection of these root crops compared to the control. And only a decrease in its density to 0.01-0.13 mA/sq. cm caused an increase in yield to the level obtained when using alternating current. What is the reason?

Using labeled phosphorus, it was found that alternating current above the specified parameters has a beneficial effect on the absorption of this important by plants electrical element. The positive effect of direct current also appeared. With its density of 0.01 mA/sq. cm, a yield was obtained approximately equal to that obtained when using alternating current with a density of 0.5 mA/sq. see. By the way, of the four AC frequencies tested (25, 50, 100 and 200 Hz), the best frequency was 50 Hz. If the plants were covered with grounded screening nets, then the harvest vegetable crops decreased significantly.

The Armenian Research Institute of Mechanization and Electrification of Agriculture used electricity to stimulate tobacco plants. We studied a wide range of current densities passed through cross section root layer. For alternating current it was 0.1; 0.5; 1.0; 1.6; 2.0; 2.5; 3.2 and 4.0 a/sq. m, for a constant - 0.005; 0.01; 0.03; 0.05; 0.075; 0.1; 0.125 and 0.15 a/sq. m. A mixture consisting of 50% chernozem, 25% humus and 25% sand was used as a nutrient substrate. The most optimal current densities turned out to be 2.5 A/sq. m for variable and 0.1 a/sq. m for constant with continuous supply of electricity for one and a half months. Moreover, the yield of dry mass of tobacco in the first case exceeded the control by 20%, and in the second - by 36%.

Or tomatoes. The experimenters created a constant electric field in their root zone. The plants developed much faster than the control ones, especially in the budding phase. They had larger area leaf surface, the activity of the peroxidase enzyme increased, and respiration increased. As a result, the yield increase was 52%, and this was mainly due to an increase in the size of the fruits and their number on one plant.

Direct current passed through the soil has a beneficial effect on fruit trees. This was also noticed by I.V. Michurin and successfully applied by his closest assistant I.S. Gorshkov, who in his book “Articles on Fruit Growing” (Moscow, Selsk. Liter. Publishing House, 1958) devoted an entire chapter to this issue. In this case, fruit trees go through the childhood (scientists say “juvenile”) stage of development faster, their cold resistance and resistance to other unfavorable environmental factors increase, and as a result, productivity increases. In order not to be unfounded, I will give specific example. When a direct current was passed continuously through the soil on which young coniferous and deciduous trees grew during the daylight hours, a number of remarkable phenomena occurred in their lives. In June-July experienced trees were distinguished by more intense photosynthesis, which was the result of electricity stimulating the growth of biological activity of the soil, increasing the speed of movement of soil ions, and better absorption of them by plant root systems. Moreover, the current flowing in the soil created a large potential difference between the plants and the atmosphere. And this, as already mentioned, is a factor in itself favorable for trees, especially young ones. In the next experiment, carried out under a film cover, with continuous transmission of direct current, the phytomass of annual pine and larch seedlings increased by 40-42%. If this growth rate were maintained for several years, it is not difficult to imagine what a huge benefit this would turn out to be.

An interesting experiment on the influence of the electric field between plants and the atmosphere was carried out by scientists from the Institute of Plant Physiology of the USSR Academy of Sciences. They found that photosynthesis proceeds faster, the greater the potential difference between plants and the atmosphere. So, for example, if you hold a negative electrode near a plant and gradually increase the voltage (500, 1000, 1500, 2500 V), then the intensity of photosynthesis will increase. If the potentials of the plant and the atmosphere are close, then the plant stops absorbing carbon dioxide.

It should be noted that a lot of experiments have been carried out on soil electrification, both here and abroad. This exposure has been found to alter locomotion various types soil moisture, promotes the proliferation of a number of substances that are difficult for plants to digest, and provokes a wide variety of chemical reactions, in turn changing the reaction of the soil solution. When electrically applied to the soil with weak currents, microorganisms develop better in it. Electric current parameters that are optimal for a variety of soils have also been determined: from 0.02 to 0.6 mA/sq. cm for direct current and from 0.25 to 0.5 mA/sq. see for alternating current. However, in practice, the current parameters, even on similar soils, may not result in an increase in yield. This is explained by the variety of factors that arise when electricity interacts with the soil and the plants cultivated on it. In soil belonging to the same classification category, in each specific case there may be completely different concentrations of hydrogen, calcium, potassium, phosphorus, and other elements; there may be dissimilar aeration conditions, and, consequently, the passage of its own redox processes and etc. Finally, we must not forget about the constantly changing parameters of atmospheric electricity and terrestrial magnetism. Much also depends on the electrodes used and the method of electrical influence (permanent, short-term, etc.). In short, in each specific case you need to try and select, try and select...

Due to these and a number of other reasons, soil electrification, although it helps to increase the productivity of agricultural plants, and often quite significant, but broadly practical application I haven't purchased it yet. Understanding this, scientists are looking for new approaches to this problem. Thus, it has been proposed to treat the soil with an electric discharge to fix nitrogen in it - one of the main “dishes” for plants. To do this, a high-voltage, low-power continuous arc discharge of alternating current is created in the soil and atmosphere. And where it “works”, part of the atmospheric nitrogen turns into nitrate forms, assimilated by plants. However, this happens, of course, on small area fields and quite expensive.

Another method of increasing the amount of assimilable forms of nitrogen in the soil is more effective. It involves the use of a brush electric discharge created directly in the arable layer. A brush discharge is a form of gas discharge that occurs when atmospheric pressure on a metal tip to which a high potential is applied. The magnitude of the potential depends on the position of the other electrode and on the radius of curvature of the tip. But in any case, it should be measured in tens of kilovolts. Then a brush-shaped beam of intermittent and rapidly mixing electrical sparks appears at the tip of the tip. This discharge causes the formation in the soil large quantities channels into which it passes significant amount energy and, as laboratory and field experiments have shown, contributes to an increase in the forms of nitrogen absorbed by plants in the soil and, as a consequence, to an increase in yield.

Even more effective is the use of the electro-hydraulic effect when cultivating soil, which consists in creating an electric discharge (electric lightning) in water. If you place a portion of soil in a vessel with water and produce an electric discharge in this vessel, the soil particles will be crushed, releasing a large amount of elements necessary for plants and binding atmospheric nitrogen. This effect of electricity on the properties of soil and water has a very beneficial effect on plant growth and productivity. Considering the great prospects of this method of soil electrification, I will try to talk about it in more detail in a separate article.

Another very interesting way to electrify the soil is without an external current source. This direction is being developed by Kirovograd researcher I.P. Ivanko. He considers soil moisture as a kind of electrolyte under the influence of the Earth's electromagnetic field. At the metal-electrolyte interface, in this case a metal-soil solution, a galvanic-electric effect occurs. In particular, when a steel wire is in the soil, cathode and anodic zones are formed on its surface as a result of redox reactions, and the metal gradually dissolves. As a result, a potential difference appears at the interphase boundaries, reaching 40-50 mV. It also forms between two wires laid in the soil. If the wires are located, for example, at a distance of 4 m, then the potential difference is 20-40 mV, but varies greatly depending on the humidity and temperature of the soil, its mechanical composition, the amount of fertilizer and other factors.

The author called the electromotive force between two wires in the soil “agro-EMF”; he managed not only to measure it, but also to explain the general patterns by which it is formed. It is characteristic that at certain periods, as a rule, when the phases of the moon change and the weather changes, the needle of the galvanometer, with the help of which the current arising between the wires is measured, sharply changes position - the accompanying effects are affected. similar phenomena changes in the state of the Earth’s electromagnetic field, transmitted to the soil “electrolyte”.

Based on these ideas, the author proposed creating electrolyzed agronomic fields. For this purpose, a special tractor unit uses a slot-cutter-wire-layer to distribute a steel wire with a diameter of 2.5 mm unrolled from a drum along the bottom of the slot to a depth of 37 cm. Having passed the rut, the tractor driver turns on the hydraulic system for lifting, the working body is dug out of the soil, and the wire is cut off at a height of 25 cm from soil surface. After 12 m across the field width, the operation is repeated. Note that the wire placed in this way does not interfere with normal agricultural work. Well, if necessary, steel wires can be easily removed from the soil using a unit for unwinding and winding measuring wire.

Experiments have established that with this method, an “agro-EMF” of 23-35 mV is induced on the electrodes. Since the electrodes have different polarities, between them through wet soil a closed electrical circuit arises through which a direct current flows with a density of 4 to 6 μA/sq. see anode. Passing through the soil solution as through an electrolyte, this current supports the processes of electrophoresis and electrolysis in the fertile layer, due to which necessary for plants Soil chemicals change from difficult-to-digest to easily-digestible forms. In addition, under the influence of electric current, all plant residues, weed seeds, and dead animal organisms are humified faster, which leads to an increase in soil fertility.

As you can see, in this embodiment, soil electrification occurs without an artificial source of energy, only as a result of the action of the electromagnetic forces of our planet.

Meanwhile, due to this “free” energy, a very high increase in grain yield was obtained in experiments - up to 7 c/ha. Considering the simplicity, accessibility and good efficiency of the proposed electrification technology, amateur gardeners who are interested in this technology can read about it in more detail in the article by I. P. Ivanko “Use of the energy of geomagnetic fields”, published in the journal “Mechanization and Electrification of Agriculture” No. 7 for 1985. When introducing this technology, the author advises placing the wires in the direction from north to south, and the agricultural plants cultivated above them from west to east.

With this article, I tried to interest amateur gardeners in using electrotechnology in the process of cultivating various plants, in addition to the well-known soil care technologies. The relative simplicity of most methods of soil electrification, accessible to persons who have acquired knowledge of physics even within the scope of the program high school, makes it possible to use and test them on almost every garden plot when growing vegetables, fruits and berries, flower and ornamental, medicinal and other plants. I also experimented with soil electrification DC in the 60s of the last century when growing seedlings and seedlings of fruit and berry crops. In most experiments, growth stimulation was observed, sometimes very significant, especially when growing cherry and plum seedlings. So, dear amateur gardeners, try to test some method of electrifying the soil in the coming season on any crop. What if everything turns out well for you, and all this could turn out to be one of the gold mines?

V. N. Shalamov

Markevich V.V.

In this paper we turn to one of the most interesting and promising areas of research - the influence of physical conditions on plants.

Studying the literature on this issue, I learned that Professor P. P. Gulyaev, using highly sensitive equipment, managed to establish that a weak bioelectric field surrounds any living thing and it is also known for sure: every living cell has its own power plant. And cellular potentials are not so small.

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PHYSICS

BIOLOGY

Plants and their electrical potential.

Completed by: Markevich V.V.

GBOU secondary school No. 740 Moscow

9th grade

Head: Kozlova Violetta Vladimirovna

physics and mathematics teacher

Moscow 2013

1. Introduction

1. Relevance
2. Goals and objectives of the work
3. Research methods
4. Significance of the work

1. Analysis of the studied literature on the topic “Electricity in life

plants"

1. Ionization of indoor air

1. Research methodology and technology

1. Study of damage currents in various plants

1. Experiment No. 1 (with lemons)
2. Experiment No. 2 (with apple)
3. Experiment No. 3 (with a plant leaf)

1. Study of the influence of an electric field on seed germination

1. Experiments to observe the effect of ionized air on the germination of pea seeds
2. Experiments to observe the effect of ionized air on the germination of bean seeds

1. conclusions

1. Conclusion
2. Literature

1. Introduction

“No matter how amazing electrical phenomena are,

inherent in inorganic matter, they do not go

in no comparison with those associated with

life processes."

Michael Faraday

In this work, we address one of the most interesting and promising areas of research – the influence of physical conditions on plants.

Studying the literature on this issue, I learned that Professor P. P. Gulyaev, using highly sensitive equipment, managed to establish that a weak bioelectric field surrounds any living thing and it is also known for sure: every living cell has its own power plant. And cellular potentials are not so small. For example, in some algae they reach 0.15 V.

“If 500 pairs of pea halves are collected in a certain order in a series, then the final electrical voltage will be 500 volts... It is good that the cook is not aware of the danger that threatens him when he prepares this special dish, and fortunately for him, the peas do not connect in an orderly series.This statement by Indian researcher J. Boss is based on a rigorous scientific experiment. He connected the inner and outer parts of the pea to a galvanometer and heated it to 60°C. The device showed a potential difference of 0.5 V.

How does this happen? On what principle do living generators and batteries work? Deputy Head of the Department of Living Systems, Moscow State University Institute of Physics and Technology Candidate of Physical and Mathematical Sciences Eduard Trukhan believes that one of the most important processes occurring in a plant cell is the process of assimilation of solar energy, the process of photosynthesis.

So, if at that moment scientists manage to “pull apart” positively and negatively charged particles into different sides, then, in theory, we will have at our disposal a wonderful living generator, the fuel for which would be water and sunlight, and in addition to energy, it would also produce pure oxygen.

Perhaps in the future such a generator will be created. But to realize this dream, scientists will have to work hard: they need to select the most suitable plants, and maybe even learn how to make chlorophyll grains artificially, create some kind of membranes that would allow the separation of charges. It turns out that a living cell, storing electrical energy in natural capacitors - intracellular membranes of special cellular formations, mitochondria, then uses it to carry out many works: building new molecules, drawing them into the cell nutrients, regulating your own temperature... And that's not all. With the help of electricity, the plant itself performs many operations: it breathes, moves, grows.

Relevance

Today it can be argued that the study of the electrical life of plants is beneficial to agriculture. I.V. Michurin also conducted experiments on the effect of electric current on the germination of hybrid seedlings.

Pre-sowing seed treatment – essential element agricultural technology, allowing to increase their germination, and ultimately the productivity of plants. And this is especially important in the conditions of our not very long and warm summer.

1. Goals and objectives of the work

The purpose of the work is to study the presence of bioelectric potentials in plants and to study the influence of the electric field on seed germination.

To achieve the purpose of the study, it is necessary to solve the following tasks :

1. Study of the basic principles concerning the doctrine of bioelectric potentials and the influence of the electric field on the life of plants.
2. Conducting experiments to detect and observe damage currents in various plants.
3. Conducting experiments to observe the influence of the electric field on seed germination.

1. Research methods

To accomplish the research objectives, theoretical and practical methods are used. Theoretical method: search, study and analysis of scientific and popular science literature on this issue. From practical methods research is used: observation, measurement, conducting experiments.

1. Significance of the work

The material in this work can be used in physics and biology lessons, since this important issue is not covered in textbooks. And the methodology for conducting experiments is like material for practical classes elective course.

1. Analysis of the studied literature

History of research into the electrical properties of plants

One of characteristic features living organisms – the ability to irritate.

Charles Darwin gave important irritability of plants. He studied in detail biological features insectivorous representatives flora, characterized by high sensitivity, and presented the research results in the wonderful book “On Insectivorous Plants,” published in 1875. In addition, the attention of the great naturalist was attracted by the various movements of plants. Taken together, all the studies suggested that the plant organism is surprisingly similar to the animal.

The widespread use of electrophysiological methods has allowed animal physiologists to make significant progress in this area of ​​knowledge. It was found that in animal organisms constantly arise electric currents(biocurrents), the spread of which leads to motor reactions. Charles Darwin suggested that similar electrical phenomena also take place in the leaves of insectivorous plants, which have a fairly pronounced ability to move. However, he himself did not test this hypothesis. At his request, experiments with the Venus flytrap plant were carried out in 1874 by a physiologist at Oxford UniversityBurdan Sanderson. Having connected a leaf of this plant to a galvanometer, the scientist noted that the needle immediately deviated. This means that electrical impulses arise in the living leaf of this insectivorous plant. When the researcher irritated the leaves by touching the bristles located on their surface, the galvanometer needle deflected the opposite side, as in the experiment with animal muscle.

German physiologist Hermann Munch , who continued his experiments, came to the conclusion in 1876 that the leaves of the Venus flytrap are electrically similar to the nerves, muscles and electrical organs of some animals.

In Russia, electrophysiological methods were usedN. K. Levakovskyto study the phenomena of irritability in bashful mimosa. In 1867, he published a book entitled “On the Movement of Stimulated Organs of Plants.” In the experiments of N.K. Levakovsky, the strongest electrical signals were observed in those specimens mimosas who responded most energetically to external stimuli. If a mimosa is quickly killed by heat, the dead parts of the plant do not produce electrical signals. The author also observed the appearance of electrical impulses in stamensthistle and thistle, in the petioles of sundew leaves.Subsequently it was found that

Bioelectric potentials in plant cells

Plant life is related to moisture. Therefore, electrical processes in them are most fully manifested under normal humidification conditions and fade away when they wither. This is due to the exchange of charges between the liquid and the walls of capillary vessels during the flow of nutrient solutions through the capillaries of plants, as well as with the processes of ion exchange between cells and environment. The most important electric fields for life are excited in cells.

So, we know that...

1. Wind-blown pollen has a negative charge.‚ approaching in magnitude the charge of dust grains during dust storms. Near plants losing pollen, the ratio between positive and negative light ions changes sharply, which has a beneficial effect on further development plants.
2. In the practice of spraying pesticides in agriculture, it has been found thatchemicals with a positive charge are deposited to a greater extent on beets and apple trees, while chemicals with a negative charge are deposited on lilacs.
3. One-sided illumination of a leaf excites an electrical potential difference between its illuminated and unlit areas and the petiole, stem and root.This potential difference expresses the plant’s response to changes in its body associated with the beginning or cessation of the process of photosynthesis.
4. Seed germination in strong electric field (for example, near the discharge electrode)leads to changeheight and thickness of the stem and crown density of developing plants. This occurs mainly due to the redistribution of space charge in the plant body under the influence of an external electric field.
5. The damaged area in plant tissue is always negatively chargedrelatively undamaged areas, and dying areas of plants acquire a negative charge in relation to areas growing under normal conditions.
6. Charged Seeds cultivated plants have relatively high electrical conductivity and therefore quickly lose charge.Weed seeds are closer in properties to dielectrics and can retain a charge for a long time. This is used to separate crop seeds from weeds on a conveyor belt.
7. Significant potential differences in the plant body cannot be excited‚ because plants do not have a specialized electrical organ. Therefore, among plants there is no “tree of death” that could kill living beings with its electrical power.

The effect of atmospheric electricity on plants

One of characteristic features our planet - the presence of a constant electric field in the atmosphere. The person doesn't notice him. But the electrical state of the atmosphere is not indifferent to him and other living creatures inhabiting our planet, including plants. Above the Earth at an altitude of 100-200 km, there is a layer of positively charged particles - the ionosphere.
This means that when you walk along a field, street, square, you move in an electric field, inhale electric charges.

The influence of atmospheric electricity on plants has been studied since 1748 by many authors. This year Abbe Nolet reported experiments in which he electrified plants by placing them under charged electrodes. He observed an acceleration in germination and growth. Grandieu (1879) observed that plants that were not exposed to atmospheric electricity by being placed in a wire mesh grounded box showed a 30 to 50% reduction in weight compared to control plants.

Lemström (1902) exposed plants to air ions by placing them under a wire equipped with points and connected to a high voltage source (1 m above ground level, ion current 10-11 – 10 -12 A/cm 2 ), and he found an increase in weight and length of greater than 45% (eg carrots, peas, cabbage).

The fact that plant growth was accelerated in an atmosphere with artificially increased concentrations of positive and negative small ions was recently confirmed by Krueger and his co-workers. They found that oat seeds responded to positive as well as negative ions (concentration of about 10 4 ions/cm 3 ) an increase of 60% in total length and an increase in fresh and dry weight of 25-73%. Chemical analysis above-ground parts of plants found an increase in the content of protein, nitrogen and sugar. In the case of barley there was an even greater increase (approximately 100%) in total elongation; the increase in fresh weight was not great, but there was a marked increase in dry weight, which was accompanied by a corresponding increase in protein, nitrogen and sugar content.

Warden also conducted experiments with plant seeds. He found that the germination of green beans and green peas became earlier as the level of ions of either polarity increased. The final percentage of germinated seeds was lower with negative ionization compared to the control group; germination in the positively ionized group and the control group was the same. As the seedlings grew, control and positively ionized plants continued to grow, while plants exposed to negative ionization mostly withered and died.

Influence in last years there was a strong change in the electrical state of the atmosphere; different regions of the Earth began to differ from each other in the ionized state of the air, which is due to its dustiness, gas contamination, etc. The electrical conductivity of air is a sensitive indicator of its purity: the more foreign particles in the air, the larger number ions settle on them and, therefore, the electrical conductivity of the air becomes less.
So, in Moscow 1 cm 3 air contains 4 negative charges, in St. Petersburg - 9 such charges, in Kislovodsk, where the standard of air purity is 1.5 thousand particles, and in the south of Kuzbass in the mixed forests of the foothills the number of these particles reaches 6 thousand. So where is there more? negative particles, it is easier to breathe there, and where there is dust, a person gets less of them, since dust particles settle on them.
It is well known that near fast-flowing water the air is refreshing and invigorating. It contains many negative ions. Back in the 19th century, it was determined that larger droplets in splashes of water are positively charged, and smaller droplets are negatively charged. Because larger droplets settle faster, negatively charged small droplets remain in the air.
On the contrary, the air in cramped rooms with an abundance of various kinds electromagnetic devices are saturated with positive ions. Even a relatively short stay in such a room leads to lethargy, drowsiness, dizziness and headaches.

1. Research methodology

Study of damage currents in various plants.

1. LITERATURE

1. Bogdanov K. Yu. Physicist visiting a biologist. - M.: Nauka, 1986. 144 p.
2. Vorotnikov A.A. Physics for young people. – M: Harvest, 1995-121p.
3. Katz Ts.B. Biophysics in physics lessons. – M: Enlightenment, 1971-158s.
4. Perelman Ya.I. Entertaining physics. – M: Nauka, 1976-432s.
5. Artamonov V.I. Interesting plant physiology. – M.: Agropromizdat, 1991.
6. Arabadzhi V.I. Mysteries of simple water. - M.: “Knowledge”, 1973.
7. http://www.pereplet.ru/obrazovanie/stsoros/163.html
8. http://www.npl-rez.ru/litra/bios.htm
9. http://www.ionization.ru

The biological influence of electric and magnetic fields on the body of people and animals has been studied quite a lot. The effects observed in this case, if they occur, are still unclear and difficult to determine, so this topic remains relevant.

Magnetic fields on our planet have a dual origin - natural and anthropogenic. Natural magnetic fields, so-called magnetic storms, originate in the Earth's magnetosphere. Anthropogenic magnetic disturbances cover a smaller area than natural ones, but their manifestation is much more intense, and therefore causes more significant damage. As a result of technical activities, humans create artificial electromagnetic fields that are hundreds of times stronger than the natural magnetic field of the Earth. Sources of anthropogenic radiation are: powerful radio transmitting devices, electrified vehicles, power lines (Fig. 2.1).

One of the most powerful exciters of electromagnetic waves-currents of industrial frequency (50 Hz). Thus, the electric field intensity directly under a power transmission line can reach several thousand volts per meter of soil, although due to the property of soil reducing the intensity, even when moving 100 m from the line, the intensity drops sharply to several tens of volts per meter.

Studies of the biological effects of the electric field have found that even at a voltage of 1 kV/m it has an adverse effect on the human nervous system, which in turn leads to disruption of the endocrine system and metabolism in the body (copper, zinc, iron and cobalt), disrupts physiological functions: heart rate, blood pressure, brain activity, metabolic processes and immune activity.

Since 1972, publications have appeared that examine the effect on people and animals of electric fields with intensity values ​​greater than 10 kV/m.

The magnetic field strength is proportional to the current and inversely proportional to the distance; The electric field strength is proportional to voltage (charge) and inversely proportional to distance. The parameters of these fields depend on the voltage class, design features and geometric dimensions of the high-voltage power line. The emergence of a powerful and extended source of electromagnetic field leads to a change in the natural factors under which the ecosystem was formed. Electric and magnetic fields can induce surface charges and currents in the human body (Fig. 2.2). Research has shown,

that the maximum current in the human body induced by the electric field is much higher than the current induced by the magnetic field. So, harmful effects The magnetic field appears only when its intensity is about 200 A/m. It occurs at a distance of 1-1.5 m from the line phase wires and is only dangerous for operating personnel when working under voltage. This circumstance allowed us to conclude that there is no biological influence of industrial frequency magnetic fields on people and animals located under power lines. Thus, the electric field of power lines is the main biologically effective factor in long-distance power transmission, which can be a barrier to the migration of different types of water and land fauna.

Based on the design features of power transmission (wire sag), the greatest influence of the field is manifested in the middle of the span, where the tension for ultra- and ultra-high voltage lines at the level of human height is 5-20 kV/m and higher, depending on the voltage class and line design (Fig. 1.2). At the supports, where the height of the wire suspension is greatest and the shielding effect of the supports is felt, the field strength is the lowest. Since there may be people, animals, and vehicles under power transmission line wires, there is a need to assess the possible consequences of long-term and short-term stay of living beings in electric fields of varying strengths. The most sensitive to electric fields are ungulates and humans wearing shoes that insulate them from the ground. Animal hoofs are also good insulators. The induced potential in this case can reach 10 kV, and the current pulse through the body when touching a grounded object (bush branch, blade of grass) is 100-200 μA. Such current pulses are safe for the body, but unpleasant sensations force ungulates to avoid the route high-voltage power lines in summer time .

In the action of an electric field on a person, the dominant role is played by the currents flowing through his body. This is determined by the high conductivity of the human body, where organs with blood and lymph circulating in them predominate. Currently, experiments on animals and human volunteers have established that a current density with a conductivity of 0.1 μA/cm 2 and below does not affect the functioning of the brain, since the pulsed biocurrents that usually flow in the brain significantly exceed the density of such a conduction current. At />1 μA/cm2, flickering circles of light are observed in a person’s eyes; higher current densities already capture the threshold values ​​of stimulation of sensory receptors, as well as nerve and muscle cells, which leads to the appearance of fear and involuntary motor reactions. If a person touches objects isolated from the ground in a zone of an electric field of significant intensity, the current density in the heart zone strongly depends on the state of the “underlying” conditions (type of shoes, soil condition, etc.), but can already reach these values. At the maximum current corresponding to Etah==l5 kV/m (6.225 mA); known fraction of this current flowing through the head area (about 1/3), and the head area (about 100 cm 2) current density j<0,1 мкА/см 2 , что и под­тверждает допустимость принятой в СССР напряженности 15 кВ/м под проводами воздушной линии.

For human health, the problem is to determine the relationship between the current density induced in tissues and the magnetic induction of the external field, IN. Current Density Calculation

complicated by the fact that its exact path depends on the distribution of conductivity in the tissues of the body.

Thus, the specific conductivity of the brain is determined by =0.2 cm/m, and that of the heart muscle by ==0.25 cm/m. If we take the radius of the head to be 7.5 cm and the radius of the heart to be 6 cm, then the product  R turns out the same in both cases. Therefore, one representation can be given for the current density at the periphery of the heart and brain.

It has been determined that magnetic induction, safe for health, is about 0.4 mT at a frequency of 50 or 60 Hz. In magnetic fields (from 3 to 10 mT; f=10-60 Hz) the appearance of light flickers, similar to those that occur when pressing on the eyeball, was observed.

Current density induced in the human body by an electric field with the intensity E, is calculated this way:

with different coefficients k for the brain and heart area. Meaning k=3  10 -3 cm/Hzm. According to German scientists, the field strength at which hair vibration is felt by 5% of the men tested is 3 kV/m and for 50% of the men tested it is 20 kV/m. There is currently no evidence that the sensations caused by the field cause any adverse effects. As for the relationship between current density and biological influence, four areas can be distinguished, presented in Table. 2.1

The last range of current density values ​​relates to exposure times of the order of one cardiac cycle, i.e. approximately 1 s for a person. For shorter exposures, the threshold values ​​are higher. To determine the threshold field strength, physiological studies were performed on humans in laboratory conditions at field strengths ranging from 10 to 32 kV/m. It has been established that at a voltage of 5 kV/m 80%

Table 2.1

people do not experience pain during discharges when touching grounded objects. It is this value that was adopted as a standard value when working in electrical installations without the use of protective equipment. Dependence of the permissible time of a person’s stay in an electric field with intensity E more than threshold is approximated by the equation

Fulfillment of this condition ensures self-healing of the physiological state of the body during the day without residual reactions and functional or pathological changes.

Let's get acquainted with the main results of studies of the biological effects of electric and magnetic fields conducted by Soviet and foreign scientists.

The celestial body called planet Earth has an electrical charge that creates the Earth's natural electric field. One of the characteristics of an electric field is potential, and the Earth's electric field is also characterized by potential. We can also say that in addition to the natural electric field, there is also a natural direct electric current (DC) of the planet Earth. The Earth's potential gradient is distributed from its surface to the ionosphere. In good weather for static electricity, the atmospheric electric field is approximately 150 volts per meter (V/m) near the Earth's surface, but this value drops exponentially with increasing altitude to 1 V/m or less (at 30 km altitude). The reason for the decrease in the gradient is, among other things, the increase in atmospheric conductivity.

If you wear clothes made of a good insulator, which is an excellent dielectric, for example clothes made of nylon, and use exclusively rubber shoes, and do not have any metal objects on the surface of the clothes, then the potential difference can be measured between the surface of the earth and the top of the head. Since each meter is 150 Volts, then with a height of 170 cm, at the top of the head there will be a potential difference of 1.7 x 150 = 255 Volts relative to the surface. If you put a metal pan on your head, a surface charge will collect on it. The reason for this charge collection is that nylon clothing is a good insulator and shoes are rubber. Grounding, that is, there is no conductive contact with the surface of the earth. In order not to accumulate electrical charges on yourself, you need to “ground yourself.” In the same way, objects, things, buildings and structures, especially high-rise ones, are capable of accumulating atmospheric electricity. This can lead to unpleasant consequences, since any accumulated charge can cause electric current and spark breakdown in gases. Such electrostatic discharges can damage electronics and cause fires, especially for flammable materials.

In order not to accumulate charges of atmospheric electricity, it is enough to connect the upper point to the lower (ground) with an electrical conductor, and if the area is large, then the grounding is done in the form of a cage, a circuit, but, in fact, they use what is called a “Faraday cage.”

Characteristics of atmospheric electricity

The earth is negatively charged and has a charge equal to 500,000 Coulombs (C) of electrical charge. The potential difference ranges from 300,000 Volts (300 kV), if we consider the voltage between the positively charged ionosphere and the Earth's surface. There is also a direct current of electricity of about 1350 Amperes (A), and the resistance of the Earth's atmosphere is about 220 ohms. This gives a power output of approximately 400 megawatts (MW), which is regenerated by solar activity. This power affects the Earth's ionosphere as well as lower layers, causing thunderstorms. The electrical energy that is stored and stored in the earth's atmosphere is about 150 gigajoules (GJ).

The Earth-Ionosphere system acts like a giant capacitor with a capacity of 1.8 Farads. Considering the enormous size of the Earth's surface area, there is only 1 nC of electrical charge per 1 square meter of surface.

The Earth's electrosphere extends from sea level to a height of about 60 km. In the upper layers, where there are many free ions and this part of the sphere is called the ionosphere, the conductivity is maximum, since there are free charge carriers. The potential in the ionosphere can be said to be leveled, since this sphere is essentially considered a conductor of electric current; there are currents in gases and a transfer current in it. The source of free ions is the radioactivity of the Sun. The flow of charged particles coming from the Sun and from space “knocks” electrons out of gas molecules, which leads to ionization. The higher you are from the sea surface, the lower the conductivity of the atmosphere. At the sea surface, the electrical conductivity of air is about 10 -14 Siemens/m (S/m), but it increases rapidly with increasing altitude, and at an altitude of 35 km it is already 10 -11 S/m. At this altitude, the air density is only 1% of that at the surface of the sea. Further, with increasing altitude, the conductivity changes non-uniformly, because the Earth’s magnetic field and photon fluxes from the Sun influence. This means that the conductivity of the electrosphere above 35 km from sea level is non-uniform and depends on the time of day (photon flux) and on the geographical location (Earth’s magnetic field).

In order for an electrical breakdown to occur between two flat parallel electrodes (the distance between which is 1 meter), which are located at sea surface level, in dry air, a field strength of 3000 kV/m is required. If these electrodes are raised to a height of 10 km from sea level, then only 3% of this voltage will be required, that is, 90 kV/m is sufficient. If the electrodes are brought together so that the distance between them is 1 mm, then a breakdown voltage will be required 1000 times less, that is, 3 kV (sea level) and 9 V (at an altitude of 10 km).

The natural value of the Earth's electric field strength at its surface (sea level) is about 150 V/m, which is much less than the values ​​required for a breakdown between the electrodes even in a gap of 1 mm (3 kV/m required).

Where does the Earth's electric field potential come from?

As mentioned above, the Earth is a capacitor, one plate of which is the surface of the Earth, and the other plate of the supercapacitor is the region of the ionosphere. On the surface of the Earth the charge is negative, and behind the ionosphere it is positive. Just like the surface of the Earth, the ionosphere is also a conductor, and the layer of atmosphere between them is an inhomogeneous gas dielectric. The positive charge of the ionosphere is formed due to cosmic radiation, but what charges the Earth's surface with a negative charge?

For clarity, it is necessary to remember how a conventional electrical capacitor is charged. It is included in an electrical circuit to a current source, and it is charged to the maximum voltage value on the plates. For a capacitor like the Earth, something similar happens. In the same way, a certain source must turn on, current must flow, and opposite charges are formed on the plates. Think about lightning, which is usually accompanied by thunderstorms. These lightning bolts are the very electrical circuit that charges the Earth.

It is lightning striking the surface of the Earth that is the source that charges the surface of the Earth with a negative charge. Lightning has a current of about 1800 Amperes, and the number of thunderstorms and lightning per day is more than 300. A thundercloud has polarity. Its upper part at an altitude of approximately 6-7 km at an air temperature of about -20°C is positively charged, and its lower part at an altitude of 3-4 km at an air temperature of 0° to -10°C is negatively charged. The charge at the bottom of a thundercloud is enough to create a potential difference with the Earth's surface of 20-100 million volts. The charge of lightning is usually on the order of 20-30 Coulombs (C) of electricity. Lightning strikes in discharges between clouds and between clouds and the surface of the Earth. Each recharge requires about 5 seconds, so lightning discharges can occur in this order, but this does not mean that a discharge will necessarily occur after 5 seconds.

Lightning

An atmospheric discharge in the form of lightning has a rather complex structure. In any case, this is a phenomenon of electric current in gases, which occurs when the necessary conditions for gas breakdown are achieved, that is, the ionization of air molecules. The most curious thing is that the Earth's atmosphere acts like a continuous dynamo that charges the Earth's surface negatively. Each lightning discharge strikes under the condition that the Earth's surface is devoid of negative charges, which provides the necessary potential difference for the discharge (gas ionization).

As soon as lightning strikes the ground, the negative charge flows to the surface, but after that the lower part of the thundercloud is discharged and its potential changes, it becomes positive. Next, a reverse current occurs and the excess charge that reaches the surface of the Earth moves upward, charging the thundercloud again. After this, the process can be repeated again, but with lower values ​​of electrical voltage and current. This happens as long as there are conditions for the ionization of gases, the necessary potential difference and an excess of negative electric charge.

To summarize, we can say that lightning strikes in steps, thereby creating an electrical circuit through which current flows in gases, alternating in direction. Each lightning recharge lasts about 5 seconds and strikes only when the necessary conditions exist for this (breakdown voltage and gas ionization). The voltage between the beginning and end of lightning can be on the order of 100 million volts, and the average current value is about 1800 Amperes. The peak current reaches more than 10,000 Amperes, and the transferred charge is equal to 20-30 Coulombs of electricity.