Thomas Edison was undoubtedly a great man, and like every self-respecting great man, Thomas Edison had a dream. He dreamed that his name would go down in history and be entrenched in it for centuries. To achieve this goal, he was ready to do anything, even kill.
While Edison's design bureau was working tirelessly on all kinds of phonographs and kinetographs, trying to add his name to the list of the most famous inventors, electricity came into fashion. "Electricity! - Edison exclaimed. “This is what will glorify me!”
But Edison faced George Westinghouse on his path to fame and fortune. Westinghouse criticized Edison to smithereens - the whole point is that the latter relied on direct current, which is good for everyone, but it is almost impossible to transmit it over long distances, and proposed for use alternating current, ideal for driving it across wires without much loss even to the other side of the world.
Thus began the “War of the Currents,” a war between Thomas Edison and George Westinghouse that lasted more than a century.
| Thomas Edison | George Westinghouse |
As I already said, Edison was a great man, and, like every self-respecting great man, he did not back down. He saw the relative safety of direct current as the main trump card in the “War of Currents”: alternating current beat people to death, and Edison’s could spare them. And, without thinking twice, Edison began to popularize his vision of electrification, organizing public shows where he killed all kinds of animals with “evil” alternating current in front of a gullible public: mostly small and domestic, but sometimes large and wild. One of his victims was the obstinate Topsy.
Topsy the elephant was catastrophically unlucky. She worked at an amusement park on Coney Island and she did not like this job at all. True, no one was interested in her opinion, so she, defending her civil rights and freedoms, systematically killed the trainers one by one. When Topsy killed the third, the park management tried her and sentenced her to death. They fed her carrots laced with cyanide, but this did not give any result: the elephant ate the carrots with gusto and had no intention of dying. Then the management decided to hang her. Why are you surprised? A common practice, the century of Progress and Civilization is still not some kind of Middle Ages!
But it's not Topsy, it's Marie, another unfortunate animal. The Greens stood up for Topsy and the hanging had to be called off. It was then that Edison appeared, just looking for someone suitable for the role of a victim of alternating current. Topsy was the perfect fit, and in the presence of one and a half thousand onlookers, Edison electrocuted her.
But that didn't help either. And now it’s time to introduce a third character into the story - William Kemmler.
Kemmler, unlike Edison, did not consider himself a great man, but he also had his own dream - just as seemingly unattainable. He didn’t want much: just so that his own wife would stop bothering him. But the wife did not let up, she nagged Kemmler every single day and, in the end, she had to be killed. No, not electric shock. With an axe.
Kemmler was tried in 1890, right at the height of the ideological war between Edison and Westinghouse. By that time, Edison, having electrocuted more than one flock of innocent sheep, decided to switch to people: he sponsored the creation of a new instrument for carrying out executions - the electric chair. Of course, the gadget ran on alternating current. The electric chair appealed to the Americans, who always had a weakness for spectacle, and Kemmler was appointed to try out the exotic method of execution.
Westinghouse, having learned about Edison's idea, hired the best lawyers for Kemmler, but they could not do anything; he then refused to supply the equipment needed to generate alternating current to carry out the execution, but Edison obtained the necessary generator from somewhere.
Kemmler was executed on August 6, 1890. The next day, newspapers bribed by Edison came out with a scandalous headline: “George Westinghouse Killed a Man!” The electrocution made a very strong impression on the public. So strong that many Americans used Edison's ineffective current until 2007.
This seems to be a very good example of how the personal ambitions of one single person can influence the course of history and progress. However, no matter how hard Edison tried, he ultimately failed to win this war, but he managed to write his name in history as a tireless inventor and an equally tireless adventurer.
P.S. Edison killed Topsy in 1903, more than ten years after the events described, to achieve the same goals - a demonstration of the danger posed by alternating current, but the executions of animals carried out by Edison in the last decade of the 19th century were no different from the murder of Topsy, so I , without hesitation, I added this story to my story. Naturally, so that as many Americans as possible would know about this incident, Edison filmed it and showed it to everyone using a kinetoscope of his own production. I once showed one of Edison’s films - “
Investments in knowledge always give the greatest return.
Benjamin Franklin
BOX OF QUALITY PROBLEMS IN PHYSICS
ELECTRICITY
I bring to the attention of readers 50 high-quality physics problems on the topic: “Electricity”, as well as some interesting facts...
Atmospheric electricity:
Lightning over an erupting volcano.
Biological electricity:
Electric fish.
Physics and military technology:
Galvanic impact mine.
And according to tradition... a little painting :-)
The tasks are divided into three groups:
1) Electrification of bodies;
2) Conductors and dielectrics. Electricity;
3) .
Benjamin Franklin(01/17/1706–04/17/1790) - politician, diplomat, scientist, inventor, journalist, publisher. The first American to become a foreign member of the Russian Academy of Sciences.
Benjamin Franklin named one type of charge positive"+" and the other negative"–"; explained the principle of operation Leyden jar, having established that the main role in it is played by the dielectric separating the conductive plates; established the identity of atmospheric and friction-generated electricity and provided proof electrical nature of lightning; established that metal points connected to the ground remove electrical charges from charged bodies even without contact with them and proposed in 1752 lightning rod project.
Proposed an idea electric motor and demonstrated an “electric wheel” rotating under the influence of electrostatic forces; first used electric spark for the explosion of gunpowder...
David Martin(David Martin; 04/01/1737–12/30/1797) - British painter and engraver.
Electrification of bodies
Task No. 1
Why does a spark occasionally jump between the belt and the pulley on which it is worn during operation?
Task No. 2
For what purpose in explosive production should drive belts be treated with antistatic (conductive) paste and the pulleys grounded?
Task No. 3
In a belt drive, can only the belt be electrified and the pulley remain uncharged? Why? Assume that the pulley is not grounded.
Task No. 4
In textile factories, threads often stick to the combs of carding machines, become tangled and break. To combat this phenomenon, high humidity is artificially created in workshops. Explain the physical essence of this measure.
Problem #5
Why do two oppositely charged balls suspended on threads attract each other, but immediately repel each other after contact?
ATMOSPHERIC ELECTRICITY
Lightning over an erupting volcano
The occurrence of lightning over an erupting volcano is caused by: seismological processes, as well as the processes occurring in the clouds during ordinary thunderstorms. Electric charges can arise due to piezoelectric, triboelectric and similar phenomena during faults and movements of rock layers accompanying a volcanic eruption.
Charges also arise during friction between ash particles flying out of the crater of a volcano.. In ordinary thunderstorms, the potential difference, which is then discharged into lightning, occurs because heavier droplets or pieces of ice, due to their weight, accumulate in the lower layers of the thundercloud, and small, light ones are lifted by rising air currents to the upper part. They accumulate opposite charges, which, after a certain voltage, penetrate the air layer. The sum of these not yet fully studied “earthly” and “heavenly” phenomena and summons lightning over an erupting volcano.
Vesuvius opened its mouth - smoke poured out in a cloud - flames
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It has been known for almost 2000 years that volcanic eruptions are sometimes accompanied by lightning strikes. In 79 AD Pliny the Younger, watching eruption of Vesuvius, recorded that dark clouds gathered over the crater and lightning flashed.
Bryullov Karl Pavlovich(12/23/1799–06/23/1852) - Russian painter, monumentalist, prominent representative of academicism.
Pompeii- an ancient Roman city near Naples, buried under a layer of volcanic ash as a result Vesuvius eruption August 24, 79 AD.
Problem #6
Why do electricians, when working to repair electrical networks and installations, wear rubber gloves, rubber shoes, stand on rubber mats, and use tools with plastic handles?
Problem No. 7
Printing shop workers rolling rolls of paper wear rubber gloves and rubber boots. Explain why.
Problem No. 8
We cannot see, hear, touch, etc. the electric field, since it does not directly affect the senses. How can one detect the existence of an electric field?
For the curious: Term electricity(“amber”: ancient Greek ηλεκτρον – electron, "amber", English electron) was introduced in 1600 by an English naturalist William Gilbert in his essay “On the Magnet, Magnetic Bodies and the Great Magnet – the Earth,” which explains the action of a magnetic compass and describes some experiments with electrified bodies.
Problem No. 9
When stroking the cat's fur with your palm, you can notice in the dark small sparks appearing between the hand and the fur. What is the cause of sparks?
Problem No. 10
Apply a friction-electrified comb to a thin stream of water. Record what you observe in the form of a drawing and accompany it with a comment.
Problem No. 11
A question for neat and attentive housewives;-) Where does dust accumulate the fastest in your home? Why?
Problem No. 12
Why, when combing your hair with a plastic comb, does your hair seem to “stick” to it (sometimes you can hear a slight crackling sound; small sparks appear in the dark)?
Problem No. 14
Why do the smallest droplets that make up the fragrant stream of cologne, perfume, or hairspray, obtained using a spray bottle, become electrified?
Problem No. 15
Raindrops and snowflakes are almost always electrically charged. Why?
Conductors and dielectrics. Electricity
Problem No. 16
Why is it possible to electrify a glass rod by friction while holding it in your hand, but not a metal rod?
Problem No. 17
What should you do to electrify a metal object, such as a spoon?
Problem No. 18
Why can connecting to a water tap serve as a method of grounding?
Problem No. 19
Why is wet hair not electrified when combed?
Problem No. 20
Why do electrical experiments most often fail in damp weather or when indoor humidity is high?
One experience I value more than a thousand opinions,
born only from imagination...
Mikhail Vasilievich Lomonosov
Fedorov Ivan Kuzmich(1853–1915?) – Russian historical painter, genre painter.
In June 1764, Catherine II visited the house Mikhail Lomonosov and for two hours looked at “works of mosaic art, newly invented physical instruments by Lomonosov and some physical and chemical experiments».
In the picture Ivan Kuzmich Fedorov standing in front of Empress Catherine II electrostatic machine with a glass cylinder rotated by a pedal mechanism and rubbed with leather pads pressed against the glass using springs. The pads were trimmed with horsehair and connected to the ground with wire. The machine produced sparks so strong that they could ignite the ether.
Problem No. 21
Experiments have shown that black cotton thread conducts current better than white! How can you comment on this fact?
...Thunder struck. The cup of heaven is split.
The dense clouds were torn apart.
On light gold pendants
The heavenly lamps began to sway...
"Heroic whistle." Sergei Alexandrovich Yesenin
Problem No. 22
Is lightning occurring between a cloud and the Earth an electric current? between the clouds? Why can lightning cause a fire?
Problem No. 23
Lightning most often strikes trees that have large roots that penetrate deep into the soil. Why?
George Morland(George Morland; 06/26/1763–10/29/1804) - English artist.
Problem No. 24
Explain why when lightning strikes sandy soil, so-called fulgurites are formed - irregularly shaped pieces of fused quartz (sand).
For the curious: The current in a lightning discharge reaches 10–500 thousand amperes, the voltage ranges from tens of millions to billions of volts. The channel temperature during the main discharge can exceed 20000–30000°C. Lightning has also been recorded on Venus, Jupiter, Saturn and Uranus...
...You recently hugged the sky,
And lightning wrapped around you menacingly;
And you made mysterious thunder
And watered the greedy land with rain...
"Cloud". Alexander Sergeevich Pushkin
For the curious: Thunder arises as a result sudden expansion of air with a rapid increase in temperature in the lightning discharge channel. Flash of lightning we see almost as an instantaneous flash and at the same moment when the discharge occurs; after all light travels at speed 3 10 8 m/s. As for sound, it travels much slower. In the air the speed of sound is 330 m/s. That's why we hear thunder after lightning has flashed. The farther the lightning is from us, the longer the pause between the flash of light and the thunder, and, in addition, the weaker the thunder. By measuring the duration of these pauses, we can roughly estimate how far is the thunderstorm from us at the moment? how quickly it approaches us, or, on the contrary, moves away from us. Thunder from very distant lightning does not reach at all - the sound energy is dissipated and absorbed along the way. Such lightning is called lightning. Note also that the reflection of sound from the clouds explains the sometimes increased sound volume at the end of thunderclaps. However, not only the reflection of sound from clouds is explained thunderclaps ;-)
Alexander Column(Alexandrian Pillar) is one of the most famous monuments in St. Petersburg. Erected in the Empire style in 1834 in the center of Palace Square by the architect Auguste Montferrand by order of Emperor Nicholas I in memory of the victory of his elder brother Alexander I over Napoleon.
Raev Vasily Egorovich(1808–1871) – Russian painter, teacher.
Problem No. 26
The appearance of thunderstorms in the atmosphere makes it difficult to use a magnetic compass. Explain this.
Problem No. 27
During a thunderstorm, the antennas of radios and televisions should be grounded, especially those that are installed high above the ground (for example, the roofs of high-rise buildings). How, and for what purpose, is this done?
For the curious: In 1785, the Dutch physicist Van Marum Martin by the characteristic smell of freshness, as well as the oxidative properties that air acquires after passing through it electrical sparks, discovered ozone– O 3 (from ancient Greek οζω - I smell) However, it was not described as a new substance; Van Marum believed that it was formed special "electric matter". Term ozone, for its odor :-) was proposed by the German chemist Christian Friedrich Schönbein in 1840.
Problem No. 28
"Terrible revenge, 1832,
Nikolai Vasilyevich Gogol
“...When blue clouds roll across the sky like mountains, the black forest staggers to its roots, the oak trees crack and lightning, breaking between the clouds, illuminates the whole world at once - then the Dnieper is terrible!”
Observations show that lightning most often strikes wet ground near the shores of lakes, rivers, and swamps. How to explain this?
Vasnetsov Apollinariy Mikhailovich(06.08.1856–23.01.1933) – Russian artist, master of historical painting, art critic.
Problem No. 29
Why does lightning rarely strike open oil storage facilities (“oil lakes”)?
Problem #30
Why does the lower end of the lightning rod need to be buried deeper, where the layers of the earth are always wet?
Perun(Old Russian Perun) – thunder god in Slavic mythology, the patron saint of the prince and squad in the ancient Russian pagan pantheon. After the spread of Christianity in Rus', many elements of the image of Perun were transferred to the image of Elijah the Prophet ( Ilya Gromovnik). The name of Perun heads the list of gods in the pantheon of Prince Vladimir in The Tale of Bygone Years.
Shishkin Ivan Ivanovich(01/25/1832–03/20/1898) - Russian landscape painter, one of the founding members of the Association of Itinerants.
Savrasov Alexey Kondratievich(05/12/1830–09/26/1897) - Russian landscape painter, one of the founding members of the Partnership of the Wanderers.
For the curious:
Is it true that lightning prefers to strike oak trees?
If the tree is wet, the lightning current passes through the water and the tree remains unharmed. In a dry tree, current can pass into the trunk and flow through the tree sap into the ground. In this case, the sap can heat up, evaporate and, expanding, “explode” the tree. Oak suffers from lightning more often than other trees because its bark is very uneven. If lightning strikes an oak tree at the beginning of a thunderstorm, it may be that only the top of the tree gets wet, whereas a tree with smooth bark quickly becomes wet from top to bottom. Therefore, when struck by lightning, an oak tree can “explode”, but a tree with smooth bark can remain intact. A forest fire occurs in cases where several discharges occur in the lightning channel, but in the intervals between the main discharges, current continues to flow in the channel.
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Vasiliev Fedor Alexandrovich(02/22/1850–10/06/1873) - Russian landscape painter.
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For the curious: Thunderstorm - an atmospheric phenomenon, in which inside the clouds or between the cloud and the earth's surface there are electrical discharges - lightning accompanied by thunder. Typically, a thunderstorm forms in powerful cumulonimbus clouds and is associated with heavy rain, hail and strong winds. At the same time, about one and a half thousand thunderstorms are active on Earth, the average intensity of discharges is estimated as 46 lightning per second.
Thunderstorms are distributed unevenly across the planet's surface. There are approximately ten times fewer thunderstorms over the ocean than over the continents.
The intensity of thunderstorms follows the sun: Maximum thunderstorms (in mid-latitudes) occur during summer time and afternoon daylight hours. The minimum of recorded thunderstorms occurs before sunrise. Thunderstorms are also influenced by geographic features of the area: strong thunderstorm centers are located in the mountainous regions of the Himalayas and Cordilleras.
Makovsky Konstantin Egorovich(06/20/1839–09/30/1915) - Russian painter, one of the early participants in the Association of Itinerants.
Problem No. 31
Will we get a galvanic cell if we put two plates of the same metal (for example, zinc) into an aqueous solution of some acid or salt?
Problem No. 32
Why does a galvanometer indicate the presence of current if steel and aluminum wires are connected to its terminals, the other ends of which are stuck into a lemon or a fresh apple?
For the curious: Italian physicist, chemist and physiologist - Alexandro Volta, during the study "animal electricity", repeating and developing experiments Luigi Galvani, found that electric current can be “tasted” - when electric current flows through a copper wire, the tongue feels a sour taste, and the greater the current, the stronger the feeling of acid; it turns out that our language can act as a very unique ammeter;-) In 1800, Volta built the first electric current generator - “voltaic pole”. This invention brought him worldwide fame.
Problem No. 33
They say that in the Arctic in winter, when the air temperature is -50°C, the world there becomes “terribly electric.” Explain or refute this.
Problem No. 34
Why is it possible for a person to get an electric shock in very damp rooms even when touching the glass container of a light bulb?
Problem No. 35
Using the chemical action of current, it is possible to coat with a metal layer a product not only made of conductive materials, but also of dielectrics - wax, plastic, plaster, wood, plasticine, etc. How to do this?
BIOLOGICAL ELECTRICITY
Electric fish
More to the ancient Greeks it was known that stingrays have an amazing ability to hit small fish, crabs, and octopuses swimming nearby at a distance. Having accidentally found themselves close to a stingray, they suddenly began to twitch convulsively and immediately froze. They were killed electrical discharges, which generated special organs of stingrays. U common stingrays these organs are located in the tail, and in those living in warm seas electric stingrays- in the area of the head and gills. Common stingrays create voltage near 5 V, electric before 50 V. Ancient Greeks used electrogenic properties of electric stingrays for pain relief during operations and childbirth.
IN 1775 British physicist and chemist Henry Cavendish invited seven eminent scientists to demonstrate the artificial electric stingray, and let everyone feel electrical discharge, absolutely identical to what real stingray paralyzes its victims. Electric stingray model, was “powered” by battery Leyden jars and immersed in salted water. At the end of the show Henry Cavendish, ahead of his contemporaries Galvani And Volta, solemnly announced to the invitees that it was this, demonstrated by him new power some day revolutionizes the whole world!
Electric ramps(lat. Torpediniformes) - a detachment of cartilaginous fish with kidney-shaped electrical organs. They do not, however, have the weak electrical organs present on either side of the tail in the rhomboid family. sea fox, or spiny stingray (lat. Raja clavata) is the most common European species of stingrays (family: Diamondback; genus: Diamondback).
Pierre Moulin du Coudray La Blanchere(1821–1880) – French naturalist, illustrator.
Wilhelm Richard Paul Flanderky(1872–1937) – German illustrator.
Electric catfish(lat. Malapterurus electricus) is a species of bottom-dwelling freshwater fish that lives in tropical and subtropical waters of Africa. The electric catfish electrical organs located over the entire surface of the body, directly under the skin. They make up 1/4 of the catfish's body weight. Depending on the size, electric catfish capable of producing voltage, reaching 350–450 V, at current strength 0.1–0.5 A.
In many electric fish (electric eel; gymnarchus; gnatonemus - elephant fish; apteronotus - knife fish), the tail is charged negatively, the head is positively charged, but in electric catfish, on the contrary, the tail is charged positively, head negative.
Electric catfish(Malapterurus electricus),
Nile multi-feather, or bishir(Polypterus bichir),
Electric pike(Mormyrus oxyrhynchus).
Friedrich Wilhelm Kunert(Friedrich Wilhelm Kuhnert; 1865–1926) – German painter, writer and illustrator.
Fish with electrical properties They use these properties not only for attack, but also to find potential prey, identify dangerous opponents, and navigate unlit or murky water. Electric field around the electric fish also leads to electrolysis of water, which results in enrichment of water with oxygen, which attracts fish and frogs, thereby making it easier for electric fish to find prey.
Not all fish have electrical properties. The number of living beings that have special organs for generation and perception of electric fields, not that big. Nevertheless, in any living organism and even in individual living cells, electrical voltages; they are called biopotentials. "Biological electricity" is an integral property of all living matter. It occurs during the functioning of the nervous system, during the work of glands and muscles. So, working heart muscle creates on the surface of the body rhythmically changing electrical potentials. The change in these potentials over time can be recorded in the form electrocardiograms, allowing the specialist to judge the work of the heart.
We continue to solve problems ;-)
Current strength. Voltage. Resistance
Problem No. 36
Two dissimilar metal plates immersed in an aqueous solution of salt, alkali or acid always form a galvanic cell. Is it possible to obtain a galvanic cell from two identical metal plates, but immersed in different solutions?
Problem No. 37
A lamp and an ammeter were connected in series with the battery and this circuit was closed with the ends of conductors dipped in a solution of copper sulfate. Will the ammeter reading change if the solution is heated?
Problem No. 38
When zinc is dissolved in an aqueous solution of sulfuric acid, the solution becomes very hot. Why is the dissolution of zinc in a Volta galvanic cell closed in an external circuit not accompanied by strong heating of the electrolyte?
Problem No. 39
Is it possible to make an electric current source using mercury, an aqueous solution of sulfuric acid, a knife and a piece of insulated aluminum wire?
Problem No. 40
At your disposal are: table salt, a bar of soap, water, pieces of insulated copper wire, a knife, a wooden stick, an aluminum pan and a large glass vessel. The length of the stick is slightly larger than the diameter of the vessel. Show how using these materials you can make a source of electric current (galvanic cell). Avoid direct contact between copper and aluminum.
PHYSICS AND MILITARY EQUIPMENT
Galvanic impact mine model 1908
“Under Water”, 1915, Alexey Nikolaevich Tolstoy
“...Andrei Nikolaevich drummed his fingers on the glass. It was impossible to remain under water; appearing on the surface meant giving yourself away and being subject to fire. Still, this was the only way to determine the exact location. He commanded a slow rise and returned to the porthole. The shadows went down. The water became noticeably brighter. And suddenly a dark ball began to descend from above, towards me. “Mina... Now let’s touch...” thought Andrei Nikolaevich and, overcoming the numbness that was pressing on his brain, he shouted: “To the left, as far to the left as possible!” The ball moved away, and a second one was approaching from the left. Without getting up, we moved forward. But even there, in the greenish twilight, cast iron balls appeared, waiting for the steel plating of the boat to touch them. "Kat" got lost in the minefields..."
How does a naval galvanic impact mine work?
In the minds of the vast majority of people, a sea mine is a large and scary horned black ball, floating freely on the waves or attached to an anchor cable under water. If a passing ship touches one of the “horns” of such a mine, an explosion will occur and the ship, along with its entire crew, will go to the bottom of the sea. Horned black balls are the most common mines are anchored galvanic impact mines.
1 – heating device; 2 – galvanic shock cap; 3 – ignition cartridge; 4 – ignition glass; 5 – anchor foot; 6 – rollers; 7 – view with minrep; 8 BB charge; 9 – weight with pin; 10 – safety device.
How does a naval galvanic impact mine work?
This mine was a further development of the galvanic impact mines of the 1898 and 1906 models. In a galvanic impact mine, the fuse was located in the cover of the only mounting neck on top of the mine, a spring buffer softened the jerks of the mine, five galvanic lead caps - the “horns” of the mine - were placed around the perimeter of its body. Each horn-cap contained a dry carbon-zinc battery with an electrolyte in a glass ampoule - a “flask”.
When the ship hit a mine, the lead cap was crushed, the “flask” broke and the electrolyte activated the battery. Current from the battery was supplied to the ignition device and ignited the detonator.
TNT was used as an explosive instead of pyroxylin, the anchor was installed on 4 rollers, and rail grips were provided to hold the mine while rolling. The mine was equipped with anti-mine cartridges - mine protectors designed by P.P. Kitkina.
To place the mine on a given recess, an automatic rod-load method was used. The procedure for preparing the mine for placement consisted of two stages. Preliminary stage: installation of galvanic shock caps, “flasks” with electrolyte, a safety device, extension of conductors and checking of all electrical circuits. The final stage involved only the installation of the ignition accessory.
Design of galvanic shock mine turned out to be so successful that, after minor modernization in 1939, under the code “model 1908/39.” it remained in service with the Russian fleet until the mid-60s.
Bordachev Ivan Vasilievich(08/13/1920...) Member of the Union of Artists of the USSR since 1957. Participant of the Great Patriotic War. Awarded the Order of the Red Star, the Order of the Patriotic War, II degree, and the medal “For the victory over Germany in the Great Patriotic War of 1941–1945.” and other medals of the USSR.
From the first days of its existence, the Russian fleet became a real forge of all kinds of new products and advanced innovations. This was most clearly manifested in the field of mine weapons. Russian sailors have priority in the creation of a sea mine, an anti-mine trawl, surface and underwater mine layers and a minesweeper. The first experiments in this area in Russia began at the beginning of the 19th century, and already on June 20, 1855, four ships of the Anglo-French squadron were blown up by sea mines placed near Kronstadt. In memory of this event, June 20 has been celebrated since 1997 as Day of specialists of the mine and torpedo service of the Russian Navy.
We continue to solve problems ;-)
Current strength. Voltage. Resistance
Problem No. 41
A student mistakenly turned on a voltmeter instead of an ammeter when measuring the current in a lamp. What will happen to the glow of the lamp filament?
Problem No. 42
It is required to halve the current in this conductor. What do I need to do?
Problem No. 43
A piece of wire was torn in half and the halves were twisted together, how did the resistance of the conductor change?
Problem No. 44
The wire was passed through a drawing machine, as a result of which its cross-section was halved (the volume did not change). How did the resistance of the wire change?
Problem No. 45
Why are copper wires not used to make rheostats?
Problem No. 46
Why is copper or aluminum wire usually used to make electrical wires?
Problem No. 47
For what purpose are wires covered with a layer of rubber, plastic, varnish, etc.? or wrapped with paper yarn soaked in paraffin?
Problem No. 48
How can you determine the length of a copper wire in plastic insulation, rolled into a large coil, without unwinding it?
Problem No. 49
Why doesn't it electrocute a bird that lands on one of the high voltage wires?
Problem #50
Why is painting small objects by spraying paint economically profitable and also harmless to the health of the worker if high voltage is created between the spray gun and the object?
An important and completely logical step on the path to studying electrical phenomena there was a transition from qualitative observations towards establishing quantitative connections and patterns, to the development basic theory of electricity. The most significant contribution to the solution of these problems was made by St. Petersburg academicians Mikhail Vasilievich Lomonosov, Georg Wilhelm Richman and American scientist Benjamin Franklin.
§ Virtual physical laboratory “Principles of Electronics”: Issue No. 1
Solving calculation problems in physics.
+ Program installation file "Virtual laboratory of the BEGINNING OF ELECTRONICS"(with file verification Dr.WEB antivirus)
+ Exciting experiments on the virtual editing table;-)
…
§ Virtual physical laboratory “Principles of Electronics”: Group C
I wish you success in making your own decision
quality problems in physics!
Literature:
§ Lukashik V.I. Physics Olympiad
Moscow: Prosveshchenie Publishing House, 1987
§ Tarasov L.V. Physics in nature
Moscow: Prosveshchenie Publishing House, 1988
§ Perelman Ya.I. Do you know physics?
Domodedovo: publishing house "VAP", 1994
§ Zolotov V.A. Questions and tasks in physics grades 6-7
Moscow: Prosveshchenie Publishing House, 1971
§ Tulchinsky M.E. Qualitative problems in physics
Moscow: Prosveshchenie Publishing House, 1972
§ Kirillova I.G. Reading book on physics grades 6-7
Moscow: Prosveshchenie Publishing House, 1978
§ Erdavletov S.R., Rutkovsky O.O. Interesting geography of Kazakhstan
Alma-Ata: Mektep Publishing House, 1989.
January 8th, 2014
A cruel and tragic topic, so the impressionable should consider reading it...
Until the 1920s, court-ordered executions of animals in the United States were commonplace. As a rule, dogs and horses were killed when their actions led to the death of people.
But elephants also suffered several executions. The elephant Topsy is considered to be the first to be executed.
The history of elephant execution in the United States is closely connected with the history of the invention of the electric chair. Thomas Edison and George Westinghouse fought to ensure that their current systems were not used in the invention of the electric chair, otherwise their names would be associated with death. Thomas Edison advocated that his direct current system be used for lighting cities, not for executions. In turn, Westinghouse did not want his AC system to be associated with death. This would have hurt their companies, both inventors believed. The execution of the elephant took place after the introduction of the electric chair as a method of execution.
Thus, the confrontation between the two inventors continued for many years.
Thomas Alva Edison. GEORGE WESTINGHOUSE
Topsy, an elephant from India, was 10 feet tall, 19 feet and 11 inches long. Topsy was brought in for the circus 28 years before her execution, and was taken to shows all over the country, working on the construction of a park in Coney Island, New York. 2 years before the event described, Topsy changed, became more aggressive and sometimes uncontrollable. Several times both spectators and circus staff had to run away from an angry elephant. Finally, at one performance in New York, she crushed 3 people to death, and for this she was sentenced to death by hanging.
On Sunday, January 4, 1903, an elephant was executed in Luna Park, Coney Island. One and a half thousand people watched the experiment.
This was a great opportunity for Edison to demonstrate the dangers of alternating current, which could be fatal even to an elephant. A cable was tied around the elephant's neck, one end of which was attached to a donkey engine and the other to a pole.
Attached to her feet were wooden sandals lined with copper. These were electrodes. They were connected via copper wire to a generator at one of Edison's power stations. A current of 6600 volts was applied! The elephant died 22 seconds after the current began, without making a sound.
Spectators were disappointed by such a speedy execution, and suspected that the elephant was given a cyanide solution a few minutes before the shock was applied (one of the police actually gave the elephant something to drink before the execution).
The experiments of Edison and Brown impressed the New York Society of Forensic Medicine, which was responsible for developing recommendations for the use of a new method of execution. The experiments were carried out in the presence of the press. Messages about the painlessness of death filled the pages of newspapers. The New York Times wrote: "Alternating current will certainly put the executioner out of work."
Although Thomas Edison emerged victorious from this confrontation, both inventors are the main characters in the history of the invention of the electric chair.
And a monument was erected to the elephant Topsy next to the place where she was executed.
Here's a video by the way:
This 1903 film by Thomas Edison records the lethal execution of elephant Topsy.
One of the most notorious cases of elephant executions in US history is the execution that occurred in Tennessee on September thirteen, 1916.
On September 12, 1916, the Sparks Brothers circus group came to perform in Kingsport, Tennessee. They brought with them a 30-year-old elephant, Mary, who was watched during breaks between performances by a certain Red Eldridge, who had just been adopted and had no experience in handling animals. At that time, the elephant was a curiosity, few people had even seen it in a picture, but here it was so huge, and besides, it could play 25 melodies on musical horns.
Before one of the performances, Eldridge pierced her sensitive ear with a hook - in this way he tried to take her on stage. Mary was furious. She grabbed him with her trunk, threw him to the ground and began to trample him, beating him to death.
Panic ensued. They opened fire on the elephant, but medium-caliber bullets were useless. Then Sheriff Hickman “arrested” Mary and locked her in a cage next to the city jail so that everyone could see how true Charlie Sparks’ assurances were that the animal would not harm anyone. Residents of neighboring towns said they would not accept the circus as long as the deadly elephant was alive. It is unknown how many people she is responsible for the death of (according to some sources, 3, according to others, 8).
It is said that the condemned elephant was shot 5 times with a .32 caliber rifle (12.40-13.10 mm bullet diameter), but could not be killed. It was also proposed to tear the elephant into pieces by tying it to two locomotives. Then, in order not to torture the animal, it was proposed to kill the elephant with an electric shock. A kind of electric chair for an elephant. But under public pressure, the Sparks brothers made a terrible decision - the next day Mary was hanged from a crane in front of a crowd of spectators.
About 5,000 people gathered. However, the execution did not go as planned. The chain by which the elephant was hanged could not bear the weight and broke. Mary fell and broke her hip.
But she was hanged again, this time successfully. Mary was buried near the place of execution.
And later, the name of Charlie Spark, despite the events of September 13, 1916, adorned the circus corridor of fame and is still the hallmark of the circus.
On June 28, 1970, a year before I was born, the elephant Vova ran away from the Yerevan Zoo: first he came out of the enclosure and a group of zoo workers tried to bring him back, and then a real drama unfolded. And even today, many years later, it is not known for certain what caused it.
The elephant Vova was brought to the USSR from India at the age of one: he lived in Russia, and then in one of the zoos in Ukraine. Here he even took part in circus performances and went on tour with his trainer Ivan Shcherban. When the Great Patriotic War began, the animals were urgently evacuated. Only Vova remained in Ukraine: transporting such a giant required an equally huge vehicle, which was in short supply during the outbreak of the war. And even before animals, when the enemy was invading the territory of our homeland deeper and deeper every day? The trainer and the elephant walked south. Together they experienced many hungry and cold days and sleepless nights. At one of the stations they even came under fire from the Messers, and Elephant covered Ivan with his body. Years later, Ivan told one of the Russian prose writers about this incident, and he included this story in his memoirs. But I think that the plot of the old Soviet film “The Soldier and the Elephant” with Frunzik Mkrtchyan was copied specifically from Vova and Ivan, and only then remade in a more ideologically necessary way. In the fall of 1941, the trainer and the elephant reached Yerevan, and Vova was placed in a zoo that was just under construction.
Soon Ivan was sent to the front, but before he could reach Rostov, he was called back: the elephant refused to obey anyone else. Ivan returned, and since then they have never been apart. The elephant calmly walked around the zoo, followed its owner everywhere and was very nervous when he disappeared from his field of vision. Vova helped with the housework when his new enclosure was being built, helping the workers drag building materials. He also looked after Ivan’s daughters, and put children from the surrounding area on his back and carried them around the zoo. But when the war ended and the zoo was opened to visitors, Vova was locked in an enclosure. He lived in the Yerevan Zoo for 30 years: over the years he grew even more, and his food needs also increased. But the maintenance standards and daily diet of the elephant remained the same. Once, getting hungry, the Elephant tore down one of the borders of the enclosure, climbed out and climbed the mountainside, and began to greedily eat the grass. Zoo workers realized that he was living from hand to mouth, but there was no way to increase the ration - the zoo was supplied with a strictly limited amount of food. And then, by unspoken agreement, they decided not to restore the border of the enclosure so that the animal could sometimes go free.
But on June 28, 1970, Vova again destroyed the enclosure and headed towards the exit of the zoo. They say that when Vova was still allowed to walk freely around the territory, he developed a favorite pastime: pushing stalled cars. We have a very steep climb there and cars driving along the highway often stopped near the zoo. So, like Vova, he learned to help them. Sometimes he spent the whole day pushing Willys and Studebakers with his forehead, regardless of whether there was a need for it or not. So that day, leaving the zoo, he began to run up to cars, which caused people to panic.
I don’t really believe in this, because if people knew that the Elephant has the ability to push cars, why did they panic when he jumped out again? I don’t know... My father was there and said that the Elephant attacked the trolleybus and began to push it: the people sitting in the cabin were screaming in fear. Fortunately, the driver suddenly pulled away and drove away. Vova then switched to passenger cars and damaged his tusk. He was in great pain and became even more furious.
The Yerevan City Council began to take emergency measures - blocking the streets, and the elephant, surrounded by a huge crowd, ran down Myasnikyan Avenue. The authorities called in soldiers and military equipment, but they refused to shoot at everyone’s favorite. Ivan, to whom the elephant no longer obeyed, could not help. Then an order came from Moscow and the soldiers opened fire: a couple of bullets hit the elephant in the head, which made him even more brutal. But the bullets also hit rocks and could ricochet into people, so the shooting was stopped almost immediately.
Now it was possible to return Vova to the zoo only with the help of a tank.
Seeing the approaching car, the elephant ran towards the zoo. It seemed that there was hope that everything would be resolved well. But having reached the gate, the elephant refused to enter it. They tried to push the wounded animal into the zoo territory with a tank, and then the machine began to knock him down and iron him. As my father said, his most terrible memory is of a still breathing elephant, onto which a tank had climbed, which was moving rhythmically in time with the last rhythms of the elephant’s life. As other sources already testify, Ivan also fell unconscious there, and then lay in the hospital for a long time, experiencing shock. A year later, he brought a new elephant from Brest to Yerevan for the zoo. But several years after the events described, he killed Ivan in a fit of rage... Disputes about why Vova went mad continue to this day. They say that after an autopsy it turned out that the elephant had stones in its kidneys, which that day made themselves felt and caused terrible pain. According to another version, and my dad insists on it, the elephant was worried about the death of his girlfriend Tikki, with whom he lived for 15 years. By the way, he always relives this story when he tells it. Maybe also because he is the namesake of an elephant?
Finally, I will say that the next day after the tragedy, our central newspapers reported that the elephant that had escaped from the zoo was safely returned to its enclosure. The country's leadership and Moscow could not allow information to get out that in the USSR its army was shooting at everyone's favorite, even if he was enraged. But this real story has become one of the legends of Yerevan, which its residents have been retelling to their children and grandchildren for decades. Each time with new details. But one thing was and remains unchanged in these stories - a touching love for the elephant and the feeling of guilt that never left us that this happened in our city.
I can also show you who he is, but here are the gifs. That’s so interesting The original article is on the website InfoGlaz.rf Link to the article from which this copy was made -