Around the axis. It is named after its inventor, French scientist Jean-Leon Foucault, who first demonstrated its action in 1851. At first glance, there is nothing complicated in the design of a pendulum. This is a simple ball suspended from a dome tall building on a long rope (67 meters during the first experiment). If you push the pendulum, then after a few minutes the ball will not move in a straight line but “write out figure eights.” This movement gives the ball the rotation of our planet.
Now the original device is kept in the Parisian Museum of Crafts in the Church of St. Martin in the Fields, and its copies are widely circulated and used in numerous natural history museums. In our native lands, for some reason, Foucault’s pendulum was used as an argument in favor of the non-existence of God. However, the innocent visual aid was destined for wider fame - literary. For it served as the title for a famous novel.
Umberto Eco's work “Foucault's Pendulum” is rightfully considered an example of postmodernism. The author - a very well-read and erudite person - literally bombards the reader with quotes, allusions and links to others literary works, historical facts and sources. Fans of this writer's work are advised to read his books with a large encyclopedic dictionary at hand. But Eco does not want to shock people with his knowledge and enlighten people - his plan is more grandiose.
The premise of the book seems quite realistic: student Casaubon writes a scientific work about the Knights Templar. He becomes friends with Belbo and Dtotallevi, employees of the Garamon publishing house. Further, the narrative slightly slides from the solid ground of reality into the foggy region of untested hypotheses, assumptions, esoteric fantasies and myths. Readers are bombarded with historical facts about the Knights Templar, as well as lengthy quotes from Kabbalah, the “Chemical Wedding” of the Rosicrucians, as well as Gnostic formulas and information about magical meaning numbers among the Pythagoreans. The main character of the novel “Foucault’s Pendulum” thinks about the posthumous fate of the Templar organization, especially after a certain colonel, coming to the publishing house, leaves them the “Plan of the Knights of the Order of the Temple,” which is written for centuries. The fact that the next day the military man disappears without a trace only strengthens Casaubon's confidence that the document is not a fake.
Gradually main character I have completely lost the solid ground of truth under my feet. Paulicians and Rosicrucians, Assassins, Jesuits, and Nestorians replace him real people. Casabon himself becomes an “obsessed”, completely believing in the Plan, although his friend Leah assures that the document is just the calculations of a seller from a flower shop. But it’s too late: the hero’s overheated imagination tells them that they should look for the tellurgical axis of the world in the Parisian Church of St. Martin, where the Museum of Crafts is now located and where Foucault’s pendulum swings under the dome. There they are attacked by a crowd of other “obsessed” people who want to take possession of the plane and open the key to absolute power - Hermeticists, Gnostics, Pythagoreans and alchemists. They kill Belbo and Leah.
What did Umberto Eco want to say in the novel “Foucault’s Pendulum”? That esotericism is an opium for intellectuals, like religion is for the people? Or what nav, as soon as you touch it, it crawls out real world like from Pandora's box? Or that the search for the golden key, with which one can control the whole world, turns out to be the seeker becoming a pawn in a game of unknown forces? The author leaves the answer to this question to the reader himself.
Foucault's pendulum - what is it and what is it eaten with?
For conducting an experiment with a pendulum, Jean Foucault was awarded the Legion of Honor, the highest award in France.
It gets its name from the name of a French physicist-astronomer and is used to experimentally demonstrate the daily rotation of the Earth. The first experiment with a pendulum was carried out by Jean Foucault in the basement of a house at night, in January 1851. He attached a two-meter long hardened steel wire to the top of the cellar vault and suspended a 5-kilogram brass ball from it. Taking the ball to the side, fixing it with a thread near one of the walls, Foucault burned the thread, giving the pendulum the opportunity to swing freely. And within half an hour he witnessed the rotation of the Earth. On next stage In his experiment, the scientist took a load already weighing 28 kg and suspended it from the top of the dome on a wire 67 m long. Jean Foucault attached a metal point to the end of the load. The pendulum oscillated over a round fence, along the edge of which sand was poured. With each swing of the pendulum, a sharp rod attached to the bottom of the weight dropped sand approximately 3 mm from the previous location. After a couple of hours, it became clear that the swing plane of the pendulum was turning clockwise relative to the floor. In an hour, the plane of oscillation rotated more than 11 degrees, and in about 32 hours it made a full revolution and returned to its previous position. Foucault thus proved that if the surface of the Earth did not rotate, the pendulum would not show a change in the plane of oscillation. After the experiment was repeated in a narrow circle of people, the future French Emperor Napoleon III invited Foucault to repeat the experiment publicly under the dome of the Pantheon in Paris.
Geography of pendulums
The plane of rotation of the pendulum is affected by geographic latitude places where it is installed. If, for example, it is placed on the Northern or South Pole, then it will make a revolution in 24 hours. And a pendulum mounted on the equator will not rotate at all. Another factor is the length of the suspension. Long pendulums rotate faster.
After the experiment of the French astronomer, the Foucault pendulum began to be used all over the world. Existing devices are designed according to the same principle and differ from each other only in technical parameters and the design of the sites on which they are installed.
From 1931 to 1986, the 98 m long Foucault pendulum could be seen in St. Isaac's Cathedral in St. Petersburg. During the excursion, visitors could observe the experiment: the plane of rotation of a pendulum suspended under the dome was rotated, and the rod was knocked down Matchbox on the floor away from the plane of rotation. In 1986, the pendulum was removed and placed in the basement of St. Isaac's Cathedral due to a malfunction suspension mechanism. A dove, the original inhabitant of this place, was placed on a hook under the dome. For 30 years, the Foucault pendulum was in storage, but last year it was taken out again. A single demonstration of his work was planned for Cosmonautics Day, and then it became part of the museum exhibition. Director of the St. Isaac's Cathedral State Municipal Enterprise Nikolai Burov suggested that the city authorities display the pendulum on the square in front of the cathedral, but this initiative did not find support. By the way, the pendulum hanging in St. Isaac's Cathedral was the largest in the world. The length of its thread is 98 m, and the bronze pendulum weighs 54 kg.
Today in our country, in addition to the Novosibirsk planetarium, the operating Foucault pendulum can also be viewed in the Moscow planetarium (there is a pendulum with a thread length of 16 m and a ball mass of 50 kg), the Siberian Federal University(thread length – 20 m). Right now, pendulums are swinging in the St. Petersburg (string length - 8 m) and Volgograd (weighing 12 kg and string length 8.5 m) planetariums, as well as in the atrium of the seventh floor of the Fundamental Library of Moscow State University, at the Volga Federal University in Kazan. Another Foucault pendulum is located in Barnaul at Altai State Technical University. I.I. Polzunov at the Department of Experimental Physics. The length of its thread is 5.5 m.
The largest Foucault pendulum in the CIS and one of the largest in Europe was installed at the Kiev Polytechnic Institute. The bronze ball weighs 43 kg and the length of the thread is 22 m.
There are about 20 models of Foucault pendulums in the world, including in the USA, France, Romania, Australia, Kuwait and other countries. Giant pendulums of this kind are now common exhibits in some major museums, including the Smithsonian Museum in Washington and the Science Museum in London. The headquarters of the United Nations in New York also has its own pendulum, and the tallest active Foucault pendulum in the world is located in the Oregon Convention Center, its thread is 27.4 m long.
It’s possible to repeat the astronomer’s experience at home
The editors of the magazine “All about New Buildings” studied ways to make a Foucault pendulum at home. The above options can be useful, for example, for visually demonstrating to children the daily rotation of the Earth.
Option 1. Tie a string to a pencil with a small round weight, such as a nut. Place a ruler on the table and, holding the pencil horizontally, push the pendulum so that it swings along the ruler. Next, you need to gradually rotate the pencil in a horizontal plane. Turning the pencil will not affect the pendulum; it will still swing along the ruler. During this experiment there should be no wind or draft that could affect the pendulum.
Option 2. You can turn the stool upside down and attach a wooden stick or metal tube at the ends of its two legs, diagonally, and tie a pendulum exactly in the middle of this structure. Make it move so that the plane of its swing passes between the legs of the stool. Slowly rotate the stool around its vertical axis. Now the pendulum is swinging in a different direction. In fact, it still swings the same way, and the change occurred due to the rotation of the stool itself, which in this experiment plays the role of the planet Earth.
Option 3. Take wooden board 50–60 cm long, 12–15 cm wide and 2–3 centimeters thick. Attach a U-shaped stand made of narrow wooden slats. The height of the stand should be about 30–40 cm. Drill a vertical hole in the middle of the top crossbar and insert a piece of wire into it, bending the upper end to hold it in the hole. Bend the lower end of the wire with a hook, the pendulum will be suspended from it. This hook should rotate freely in its socket. Using a thin cord, hang some heavy weight (a large nut or a ball from a bearing, wrapped in fabric) from the hook. Swing the pendulum so that its swing does not exceed the length of the stand. By rotating the stand around its vertical axis counterclockwise, you will thereby repeat in miniature the rotation of the Earth from west to east. Thus, the model of the Earth rotates, and the pendulum continues to oscillate in the plane in which it was launched.
Let us recall that the Foucault pendulum is an experimental device with which you can visually observe the daily rotation of the Earth. It is a fairly long (in original design Jean Foucault's length was 67 m) steel wire on which a load is suspended. Over time, the plane of oscillation of the pendulum changes, slowly turning in the direction opposite to the direction of rotation of the Earth, and geographical position The (latitude) of the instrument affects the rate of change.
It is very difficult to imagine a plane stationary relative to the stars and, accordingly, rotating relative to the Earth. The Earth is too large, its apparent “flatness” is too familiar to us, and it is completely impossible to feel the rotation on ourselves. The Foucault pendulum clearly demonstrates to us the effect of daily rotation, but even looking at it, it is not always easy to understand and accept its “indications”.
Plate; three forks; wine stopper; lime or any other item of similar parameters that can be easily pierced with a needle; two sewing needles; spool of thread; salt.
Imagine a situation: your son comes up to you and asks: Dad, I read about some kind of Foucault pendulum, which proves that the Earth rotates, and I didn’t understand anything. Can you explain it to me in a simpler way? Of course, you answer and build a model of a pendulum right in the kitchen.
Limes and needles
You can build a model from almost anything, you can make it more beautiful, larger, more photogenic. We preferred to use simple objects, which can be found in almost any kitchen in a matter of minutes. You don't even need to go to the store.
If we rotate the plate evenly (for example, by placing it on a spinning disk), the tip of our pendulum will describe a figure on the salt similar to the figure described by a real Foucault pendulum.
So, a plate, three forks, two needles, a cork, some kind of weight (lime, potato, small apple), a spool of thread, salt. The plate plays the role of the Earth, and the table on which it stands acts as a fixed coordinate system in which the Earth rotates (in other words, stars). From all this it is not difficult to build the structure shown in the first photo. The most difficult thing is to choose the length of the thread so that the tip of the needle barely touches the surface of the plate. It is very important to maintain alignment, that is, to ensure that the tip of the needle comes out from the very center of the fruit, which is used as a load.
Then we start the system - it's best to pull the load to the side and let go. The pendulum begins to oscillate. If we rotate the plate around its axis, we will find that the pendulum does not rotate with it, but continues to oscillate in a constant plane! Salt in in this case used for clarity - when the plate is turned, the tip of the needle draws a new trajectory.
The longer the thread, the longer the pendulum will oscillate with sufficient amplitude to make the experiment interesting to observe from the outside.
Now it is enough to imagine that the plate is very large - with a diameter of the Earth. And it rotates, as Galileo said according to legend, on its own, just as we rotate a plate with our hands. And the Foucault pendulum, descending from the dome of the Moscow Planetarium or the Parisian Pantheon, draws an intricate figure, constantly changing the plane of oscillation relative to the Earth. More precisely, it is the Earth that changes its position relative to the pendulum. Like a plate.
After the October Revolution of 1917, St. Isaac's Cathedral ceased to exist as a temple: all church valuables were confiscated, the rector was arrested and services were stopped. On April 12, 1931, one of the first in the cathedral was opened Soviet Russia anti-religious museums. The day before, on the night of April 11-12, an experiment with a Foucault pendulum was shown for the first time inside in the presence of seven thousand spectators.
What is a Foucault pendulum?
The Foucault pendulum is used to experimentally demonstrate the daily rotation of the Earth. The first experiment with a pendulum was carried out on the night of January 8, 1851 by French physicist and astronomer Jean Foucault in the basement of a house. After the experiment was repeated in a narrow circle of people, the future French Emperor Napoleon III invited Foucault to repeat the experiment publicly under the dome of the Pantheon in Paris.
During the experiment, the scientist took a weight weighing 28 kilograms and suspended it from the top of the dome on a wire 67 meters long. The scientist attached a metal point to the end of the weight. The pendulum oscillated over a round fence, along the edge of which sand was poured. With each swing of the pendulum, a sharp rod attached to the bottom of the load dropped sand approximately three millimeters from the previous place. After about two and a half hours, it became clear that the swing plane of the pendulum was turning clockwise relative to the floor. In an hour, the plane of oscillation rotated more than 11 degrees, and in about 32 hours it made a full revolution and returned to its previous position. Foucault thus proved that if the surface of the Earth did not rotate, Foucault's pendulum would not show a change in the plane of oscillation.
By the way, the plane of rotation of the pendulum is affected by both the latitude of the place where it is installed and the length of the suspension (long pendulums rotate faster). For example, a pendulum placed at the North or South Pole will rotate every 24 hours. And a pendulum mounted on the equator will not rotate at all, the plane will remain motionless.
Foucault's pendulum subsequently became widespread in many countries. Existing devices are basically designed according to the same principle and differ from each other in technical parameters and the design of the sites on which they are installed.
In Russia, an active Foucault pendulum can be viewed in the Moscow Planetarium, Siberian Federal University, in the atrium of the seventh floor of the Fundamental Library of Moscow State University, the St. Petersburg and Volgograd Planetariums, and at the Volga Federal University in Kazan.
From 1931 to 1986, a 98-meter-long Foucault pendulum could be seen in St. Isaac's Cathedral in St. Petersburg. During the excursion, visitors to the cathedral could observe the experiment: the plane of rotation of the pendulum suspended under the dome was turned - and the rod knocked down a matchbox on the floor away from the plane of rotation of the pendulum.
About the fate of the St. Petersburg Foucault pendulum
In 1986, the pendulum was removed and placed in the basement of St. Isaac's Cathedral due to a malfunction of the suspension mechanism. A dove, the original inhabitant of this place, was placed on a hook under the dome. For 30 years, the Foucault pendulum was in storage, but last year it was taken out again. A single demonstration of his work was planned for Cosmonautics Day, and then it became part of the museum exhibition. Director of the St. Isaac's Cathedral State Municipal Enterprise Nikolai Burov suggested that the city authorities display the pendulum on the square in front of the cathedral, but this initiative did not find support. In connection with the current controversial situation in the fate of the cathedral and the possible relocation of the museum, Burov said that the Foucault pendulum as a museum exhibit would move along with the rest of the collection.
Photo: rewizor.ru, krugosvet.ru, pikabu.ru, realigion.me, gazeta.ru, img-fotki.yandex.ru
Jean Bernard Leon Foucault - French physicist, member of the Paris Academy of Sciences, was born in Paris on September 18, 1819. In addition to the Foucault pendulum, the scientist designed a gyroscope, developed a method for measuring the speed of light in air and water, and also created a method for silvering mirrors.
Jean Bernard Leon Foucault. No later than 1868. Photo: Commons.wikimedia.org / Léon Foucault
What is a Foucault pendulum?
In the mid-19th century, Jean Foucault invented a device that clearly demonstrates the rotation of the Earth. First, the scientist conducted an experiment in a narrow circle. Louis Bonaparte later learned about this experience. In 1851, the future French Emperor Napoleon III invited Foucault to repeat the experiment publicly under the dome of the Pantheon in Paris.
During the experiment, Foucault took a weight weighing 28 kg and suspended it from the top of the dome on a wire 67 m long. The scientist attached a metal point to the end of the weight. The pendulum oscillated over a round fence, along the edge of which sand was poured. With each swing of the pendulum, a sharp rod attached to the bottom of the load dropped sand approximately three millimeters from the previous place. After about two and a half hours, it became clear that the swing plane of the pendulum was turning clockwise relative to the floor. In an hour, the plane of oscillation rotated by more than 11°, and in about 32 hours it made a full revolution and returned to its previous position. Foucault thus proved that if the surface of the Earth did not rotate, Foucault's pendulum would not show a change in the plane of oscillation.
For conducting this experiment, Foucault was awarded the Legion of Honor, France's highest award. Foucault's pendulum subsequently became widespread in many countries. Existing devices are basically designed according to the same principle and differ from each other in technical parameters and design of the sites on which they are installed.
How can the plane of rotation of a pendulum change?
The plane of rotation of the pendulum is affected by both the latitude of the place where it is installed and the length of the suspension (long pendulums rotate faster).
A pendulum placed at the North or South Pole will rotate every 24 hours. A pendulum mounted on the equator will not rotate at all, the plane will remain motionless.
Foucault pendulum in the Paris Pantheon. Photo: Commons.wikimedia.org / Arnaud 25
Where can you see a Foucault pendulum?
In Russia, the operating Foucault pendulum can be viewed in the Moscow Planetarium, Siberian Federal University, in the atrium of the 7th floor of the Fundamental Library of Moscow State University, the St. Petersburg and Volgograd Planetariums, and at the Volga Federal University in Kazan.
Foucault pendulum in the Interactive Museum "Lunarium" of the Moscow Planetarium
Until 1986, a 98 m long Foucault pendulum could be seen in St. Isaac's Cathedral in St. Petersburg. During the excursion, visitors to the cathedral could observe the experiment - the plane of rotation of the pendulum was rotated, and the rod knocked down a matchbox on the floor away from the plane of rotation of the pendulum.
The largest Foucault pendulum in the CIS and one of the largest in Europe was installed at the Kiev Polytechnic Institute. The bronze ball weighs 43 kilograms, and the length of the thread is 22 meters.