© Erashov V.M.

According to the existing theory, it is believed that the Foucault pendulum performs a daily rotation of the oscillation plane due to the Coriolis force. Is this so?
There is a fundamental theorem: the work done by forces in a potential field along a closed loop is zero. From this it follows that changes in the speed of the system are equal to zero and the path traveled by the system is equal to zero. The gravitational field is the most potential field, and the Foucault pendulum, oscillating, moves along a closed loop. Consequently, the effect of the Coriolis force on it is zero. Thus, the existing theory fundamentally contradicts the fundamental principles of modern science.
Another point that we should note is if we install a Foucault pendulum at the North Pole and cock the pendulum. The pendulum ball will deviate from the Earth's rotation axis by the amount of the oscillation amplitude and acquire the kinetic energy of its rotation. Next, let’s release the ball into free oscillations; it should oscillate in the plane of minimum energy, that is, in a plane rigidly connected with the rotating Earth, and the plane of its oscillations will not rotate relative to the Earth, or rather, it will rotate together with the Earth. And in order for the pendulum to make a visible rotation (to a person on the Earth), some additional force must act on the Foucault pendulum, but not the centrifugal force of the Earth’s rotation, which, as we have determined, cannot serve as a source of rotation of the pendulum plane. Centrifugal force is only capable of shifting the equilibrium point of the pendulum away from the plumb line directed towards the center of gravity of the Earth, but it does not create rotational motion for the pendulum.
Next, we will consider one more point, if at the same North Pole we dig a mental deep well and lower a long plumb line into it. If the Earth were alone in Space, then despite the rotation of the Earth, the plumb line would always be directed strictly towards the center of mass and would not make any oscillations. This once again proves that the centrifugal force of the Foucault pendulum does not swing or rotate its plane of oscillation. But in space, in addition to the Earth, there are also other bodies, for example the Moon. Let's see how the Moon will act on the long hypothetical plumb line that we placed at the pole. Now the plumb line will be directed not strictly to the center of mass of the Earth, but to the point of attraction of the Earth-Moon system, which should always be on a straight line connecting the centers of mass of the Earth and the Moon, but at a distance proportional to the gravitational force of the Moon from the same center of mass of the Earth. In reality, such a point will be only a few tens of meters away from the Earth’s center of mass. And this point will perform a daily rotational movement relative to the center of the Earth. True, the length of the day in this case should be taken not solar, but lunar, which is equal to 24 hours 50 minutes. Thus, we have established that the presence of the Moon causes the end of the plumb line at the Earth's pole to rotate counterclockwise with a period of lunar days. And since the plumb line is the same Foucault pendulum, only not cocked, we have established that the end of any suspended pendulum at the pole performs a rotational movement with a period of a lunar day. Please note that, according to the accepted theory, the Foucault pendulum at the pole performs a rotational movement with a period of a solar day, and according to ours, a lunar day. We also note that no matter what theory we adhere to, the influence of the Moon on the rotation of the swing plane of the Foucault pendulum clearly exists, since the gravitational force of the Moon is a real thing. Another thing is how sensitive this force is for a Foucault pendulum; it may turn out that in practice it is tiny, we did not carry out calculations, and cannot be a real source of rotation of the plane of a Foucault pendulum (artificial). Why did we introduce the word artificial? The fact is that the Earth itself is a natural pendulum; the axis of rotation makes oscillatory movements relative to the center of gravity, like a metronome, including with a period of lunar days. The Earth feels exactly the lunar attraction and its main pendulum oscillates in time with the movement of the Moon, thereby performing forced oscillations. Let us recall that in addition to forced oscillations, there are also natural oscillations of the Earth’s poles with the Chandler frequency (428-430 days. ), but natural vibrations have a very high frequency to influence the speed of rotation of the plane of oscillation of artificial Foucault pendulums. For now, we will be interested only in forced oscillations with a frequency close to daily. We have established that the Earth performs forced oscillations (rotational) of the poles under the influence of the attraction of the Moon with a period of lunar days. If an artificial Foucault pendulum is installed on Earth, then its oscillations should be affected by the daily fluctuations of the Earth's poles, so they can make the plane of oscillation of the Foucault pendulum rotate. Moreover, the dependence of the rotation speed of the Foucault pendulum, both in the existing theory and in the proposed one, depends on the sine of the angle between the axis of rotation of the Earth and the location of the pendulum. That is, according to our theory, the Foucault pendulum will not rotate at the equator, but according to our theory it will receive a forced swing in the plane of the equator, that is, such a pendulum is capable of swinging without the supply of energy by a person, the energy will be supplied to the pendulum by the Moon.
We only took into account the influence of the Moon’s gravity; we also need to take into account the Sun’s gravity, although it affects terrestrial processes 2.3 times weaker than the Moon’s, but it is significant. The attraction of the Sun rotates the plane of oscillation of the Foucault pendulum with a period of a solar day. When the Earth, Moon and Sun line up, the period of solar oscillation coincides with the period of lunar oscillation, at such moments the Foucault pendulum can accelerate the speed of rotation of the oscillation plane. Isn't this the phenomenon discovered by Maurice Allais in 1954? Although we do not rule out that the Maurice Elle effect may involve other phenomena not yet known to science. For example, in the future we plan to consider the influence of a magnetic field on the rotation speed of the plane of oscillation of a Foucault pendulum, but this will be in other articles. For now we will limit ourselves to the material presented.
In this work we presented an alternative theory of rotation of the plane of oscillation of a Foucault pendulum. Let us highlight separately, we do not deny the presence of Coriolis acceleration and its influence on individual stages of swinging of the pendulum, but we assert that in general for the cycle (this is stated by the theorem about work in a potential field along a closed loop) the work of the Coriolis force is equal to zero. Let us also highlight that, according to the existing theory, the speed of rotation of the pendulum at the pole is equal to one revolution per solar day, that is, in 24 hours, and according to our theory it is equal to the lunar day of 24 hours 50 minutes. Let us also note one very interesting point: if we adhere to the traditional theory, then there should be a latitude on Earth where the speed of rotation of the pendulum by the Coriolis force coincides with the frequency of forced oscillations, that is, with the lunar day; let's call this zone the resonance zone. Calculations show that such a zone is not very far from the pole and has little effect on everyday life, since it is located in a sparsely inhabited zone, and under eternal ice, which prevents ocean waves from clearing up, if only internal ones, which can pose a danger to submarines . But according to the logic of things, there should be the next resonant zone, where the speed of rotation of the pendulum is equal to twice the lunar day, the natural oscillations coincide with the forced ones every other time. In such a zone, ocean oscillations (they are also, to some extent, a Foucault pendulum) can resonate with the circulation of the lunar gravity point. In this zone, seismic activity should be increased. Thus, this work gives scientists the right to choose, either accept an alternative theory, or adhere to the old one, but then look for resonance zones on Earth.
Primary sources
1. A.N. Matveev “Mechanics and theory of relativity”, M, 1976.
2. “Problems with the Foucault pendulum” http://qaxa.ru/zemla-luna/420-2010-02-03-16-41-48.html
06/11/2015

Yesterday, while posting the work, I was torn by doubts, based on the FUNDAMENTAL theorem of the work of forces in a potential field along a closed loop of rotation of the plane of oscillation of a Foucault pendulum, there should not be a Coriolis force, but they seem to exist, and for the Northern Hemisphere this rotation is anticyclonic. Let us recall that in an anticyclone, air masses descend and their Coriolis acceleration spins them clockwise, while in a cyclone, air masses rise and their Coriolis acceleration spins them counterclockwise (we are talking about the Northern Hemisphere). When air masses do not rise or fall, but simply move in some direction, no matter which, Cooriolis acceleration does not manifest itself, and according to theory it should not exist. The Foucault pendulum rises and falls, which means that its Coriolis acceleration twists it in one direction and then in the other. As a result, if there is no change in height, then the overall effect should be zero, that is, the pendulum should not rotate due to Coriolis acceleration (as we found out above, it can be rotated by other forces, although the period will then be proportional to the lunar day, not the solar one) . But if, in spite of everything, Coriolis acceleration rotates the pendulum with anticyclonic twist (the pendulum goes down), then the conclusion is the following - the Earth at this historical stage is COMPRESSING (!).
06/12/2015

Reviews

“When air masses do not rise or fall, but simply move in some direction, no matter which, Coriolis acceleration does not manifest itself, and according to theory it should not exist” - this is not true.
If there is a non-zero speed of movement, the Coriolis force also acts.

Coriolis acceleration acts when a moving body moves along a variable radius of rotation of the Earth, there is no change in the radius of rotation, and there is no Coriolis acceleration.

Absolutely not true. Let's say a river flows along a parallel - the radius of rotation of the Earth is constant, and the Coriolis force washes away the right bank.

I checked the university textbook “Mechanics and Theory of Relativity” by A.N. Matveeva. The answer is not in your favor, and let's stop the demagoguery here.

Why did you start swearing with “demagoguery”? This is just a scientific question, you can clarify it without swearing.
Haven't you heard that ALL rivers in the northern hemisphere, no matter where they flow, wash away the right bank due to the Coriolis force?

We are tired of our abundant knowledge, because we are pounding water in a mortar. Regarding rivers, this is a truism, but it should not be understood that the right bank is completely washed away. Have you walked along rivers yourself? The banks are washed away mainly at turns, and this is primarily a centrifugal current. The effect of Coriolis acceleration is revealed only through careful examination and collection of a mass of data. Period, we’ll stop the discussion, I wasn’t hired as your teacher. I will erase all your subsequent opuses.

You can do the laundry, Vladimir, but it’s stupid. We are not talking about the rivers themselves, but about the presence or absence of the Coriolis force. And you are wrong in the above case.
I will give a second example: the right rail in the direction of train movement (movement in one direction) in any case wears out more. And also because of the Coriolis force.

If you don’t understand this force, then how can you discuss the Foucault pendulum?

Which of us is wrong?
Your arguments are not used correctly. I do not deny the presence of Coriolis forces in Nature. Yes, the shore is being washed away and the rails are wearing out, but this does not prevent the Coriolis forces from acting when the body moves along the meridian, but not when moving along the parallel.
If you don’t believe me, then argue with the scientists who write the textbooks. Here is a quote from the textbook for universities by A.N. Matveev “Mechanics and Theory of Relativity”, M, 1976. (p. 405):
If the speed is directed parallel to the axis of rotation, then no Coriolis acceleration occurs, since in this case neighboring points of the trajectory have the same transfer speed."
End of quote.
Goodbye!

Matveev is absolutely right! like any mechanics textbook. Only the parallels are not parallel to the Earth’s rotation axis, but perpendicular. Finally, draw a three-dimensional diagram of the globe, and you will see for yourself!

If you are so meticulous and do not want to recognize motion along a constant radius as parallel to the axis of rotation, then look at the derivation of the formula for Coriolis acceleration in the same textbook. By the way, there the case of motion of a body with a constant radius of rotation is considered separately. No formulas are written here, otherwise I would give this conclusion; it is quite simple. There, centrifugal acceleration is written as the square of the sum of the relative and portable angular velocities per radius of rotation. When the square of the sum is revealed, three terms are formed (school course): the square of the first term plus the double product of the first term by the second plus the square of the second term. So, the double product of the portable angular velocity of the velocity by the relative velocity and by the radius of rotation is also called Coriolis acceleration by Matveev. It seems to formally exist when a body moves along a parallel, but Matveev also says that all three accelerations (relative, translational and Coriolis) when a body moves along a circle of constant radius are directed towards the center of rotation. If this same expression is written through absolute acceleration, then it will be reduced only to centrifugal acceleration, without any Coriolis acceleration. The physical essence of all this fuss is that when a body moves along a parallel, no accelerations that wash away the right bank or rail occur, even if one of the terms of the expansion is formally called Coriolis acceleration (the true Coriolis acceleration is always directed perpendicular to the relative speed, it is this that washes away the bank and rail. But this is only in the case of body motion along a meridian. In an arbitrary case, the motion must be decomposed into components. Vershtein?

You have confused yourself with complex cases, the presence of relative and portable accelerations. What is this for? Consider the simplest motion with constant speed. Here is the Coriolis force:

Where v is the speed of relative motion; ω is the vector of the Earth's angular velocity.

Note that the force is maximum when the vectors v and ω are perpendicular. This exactly corresponds to the case of movement along a parallel.

We have no discrepancies regarding the Coriolis value (in the broad sense). The only discrepancy is that in the case of a body moving along a parallel, for me and Matveev, I emphasize that Matveev specifically stipulates this, all accelerations are directed towards the center of rotation, and in your case the perpendicular component is taken from somewhere. The perpendicular component is present only when moving along the meridian (in the general case, a projection onto the meridian) and only in this case.

The Coriolis force is directed towards the axis of rotation when the body moves from east to west. If the movement is directed from west to east, the force acts from the center (coincides in direction with the centrifugal force).

Quote:
I don't have any "perpendicular component".
End of quote.
So we figured it out. The fact that “towards the center” or “from the center” is a tenth matter. The red thread of our dispute is whether there is a component of Coriolis acceleration when moving along a parallel, directed perpendicular to the transfer speed, because it is this that washes away the banks, wears out the rails and rotates the swing plane of the pendulum.
It turns out they were arguing in vain, there is no such component.
Thanks for the training.

Firstly, not transfer speed, but relative speed. The Coriolis force is ALWAYS perpendicular to the speed of movement. And there is such a force when moving along a parallel.
It was not in vain that they argued, and it seems that you still continue to resist :-) This is in vain!

Firstly, about terminalology. When moving along a parallel, the portable and relative speeds coincide in direction; your correction in this case does not make sense. And if we talk about the meaning, then we are talking specifically about portable speed, that is, about the speed from the rotation of the Earth (transportable), and not about the speed of the body relative to the Earth (relative).
Secondly, on account, the Coriolis acceleration is ALWAYS directed perpendicular to the relative velocity. Yes, it’s hard to argue with this, that’s how it is, but in this case the Coriolis acceleration is directed towards the center of rotation (and not somewhere to the side, Matveev also talks about this), that is, the directions of the Coriolis acceleration and the centrifugal one are either the same or opposite , depending on how the body moves (in the direction of the Earth’s rotation, or against it). You are right in only one thing, the center of rotation (for an arbitrary latitude) does not coincide with the center of gravity of the Earth, therefore there is always some kind of horizontal projection for both centrifugal and Coriolis acceleration. But this is very little consolation for you, because in the example being analyzed, the centrifugal acceleration is more than 200 times greater than the Coriolis acceleration. It turns out that for practical calculations when moving along a parallel-Coriolis acceleration, one can safely neglect it.
Total:
I am 99.5% right, and you are 0.5%.

The daily audience of the Proza.ru portal is about 100 thousand visitors, who in total view more than half a million pages according to the traffic counter, which is located to the right of this text. Each column contains two numbers: the number of views and the number of visitors.

The fact that the Earth rotates around its axis is known to every schoolchild today. However, people were not always convinced of this: it is quite difficult to detect the rotation of the Earth while on its surface. Of course, one can guess that the daily movement of celestial bodies across the celestial sphere is a manifestation of the Earth’s rotation. But we see this phenomenon precisely as the movement of the Sun and stars across the sky.

In the middle of the 19th century, Jean Bernard Leon Foucault was able to conduct an experiment that demonstrates the rotation of the Earth quite clearly. This experiment was carried out several times, and the experimenter himself presented it publicly in 1851 in the Pantheon building in Paris.

The building of the Paris Pantheon in the center is crowned with a huge dome, to which a 67 m long steel wire was attached. A massive metal ball was suspended from this wire. According to various sources, the mass of the ball ranged from 25 to 28 kg. The wire was attached to the dome in such a way that the resulting pendulum could swing in any plane.

The pendulum oscillated over a round pedestal with a diameter of 6 m, along the edge of which a roller of sand was poured. With each swing of the pendulum, a sharp rod mounted on the ball from below left a mark on the roller, sweeping away sand from the fence.

In order to eliminate the influence of the suspension on the Foucault pendulum, special suspensions are used (Fig. 4). And in order to avoid a side push (that is, so that the pendulum swings strictly in the plane), the ball is taken to the side, tied to the wall, and then the rope is burned out.

The period of oscillation of a pendulum, as is known, can be calculated by the formula:

Substituting into this formula the length of the pendulum l = 67 m and the value of the acceleration of free fall g = 9.8 m/s 2, we find that the period of oscillation of the pendulum in Foucault’s experiment was T ≈ 16.4 s.

After each period, a new mark made by the tip of the rod in the sand was approximately 3 mm from the previous one. During the first hour of observation, the plane of the pendulum's swing rotated through an angle of about 11° clockwise. The plane of the pendulum completed a full revolution in approximately 32 hours.

Foucault's experience made a huge impression on the people who observed it, who seemed to directly feel the movement of the globe. Among the spectators who observed the experiment was L. Bonaparte, who a year later was proclaimed Emperor of France by Napoleon III. For conducting an experiment with a pendulum, Foucault was awarded the Legion of Honor, the highest award in France.

In Russia, a 98 m long Foucault pendulum was installed in St. Isaac's Cathedral in Leningrad. Usually such an amazing experiment was shown - a matchbox was placed on the floor a little away from the plane of rotation of the pendulum. While the guide was talking about the pendulum, the plane of its rotation was turning and the rod mounted on the ball was knocking down the box.

The experiment was based on an experimental fact already known at that time: the plane of swing of a pendulum on a thread is preserved regardless of the rotation of the base to which the pendulum is suspended. The pendulum strives to preserve the parameters of motion in an inertial reference system, the plane of which is motionless relative to the stars. If you place a Foucault pendulum at a pole, then as the Earth rotates, the plane of the pendulum will remain unchanged, and observers rotating with the planet should see how the plane of the pendulum swings without any forces acting on it. Thus, the period of rotation of the pendulum at the pole is equal to the period of rotation of the Earth around its axis - 24 hours. At other latitudes, the period will be slightly longer, since the pendulum is affected by inertial forces that arise in rotating systems - Coriolis forces. At the equator, the plane of the pendulum will not rotate - the period is equal to infinity.

To experimentally demonstrate the daily rotation of the Earth, many universities, planetariums and libraries use a Foucault pendulum. I will tell about the temples in which this experience was demonstrated or is currently being demonstrated.

Pantheon, Paris
French physicist Jean Bernard Leon Foucault (1819-1868) first demonstrated his experiment on January 8, 1851. In the cellar of his house in Paris, the physicist performed an experiment with a pendulum 2 meters long. The experiment aroused increased interest and already in March of the same year it was carried out publicly under the dome of the Pantheon in Paris.

In the Pantheon building, the scientist suspended a metal ball weighing 28 kilograms on a steel wire 67 meters long. A point was attached to the lower part of the metal ball. The mount allowed the pendulum to swing freely in all directions. Before launching, the pendulum was moved to the side and tied with a rope, which was then burned out - this made it possible to avoid a side push. The pendulum swung over a fenced area with a diameter of 6 m. A sandy path was poured along the diameter of the area, and as the pendulum moved, its tip made marks in the sand. After a few minutes, one could notice that the plane of the pendulum's swing had changed.

In about 32 hours, the pendulum made a full revolution and outlined the trajectory of its rotation on the sand. With the help of this experiment, the daily rotation of the Earth was clearly demonstrated. The experiment can be made even more spectacular if you place some object at the edge of the pendulum’s trajectory, which will be knocked down after some time.

How does a change in the plane of oscillation of a pendulum prove the rotation of the Earth? According to the laws of physics, a pendulum does not change the plane of its swing. But the sand or objects placed for the experiment rotate along with the Earth’s surface during its daily circular motion and at some point end up in the plane of the pendulum’s swing.

The longer the thread on which the metal ball is suspended, the greater the rotation made in one period. Accordingly, when demonstrating the operation of a Foucault pendulum in very tall buildings, for example, in churches, the rotation of the Earth will be more noticeable, and the experiment itself will be more spectacular.

The photo shows a modern copy of a Foucault pendulum and a stone statue of an Egyptian cat. (Photo)

Fukusaiji, Nagasaki
In the Japanese city of Nagasaki on the island of Kyushu there is an unusual Buddhist temple complex. Fukusaiji was founded by Chinese monks from Fujian province in 1628, but was destroyed during an atomic explosion on August 9, 1945. The monastery was restored in memory of those killed in 1979. Every day at exactly 11-02, during the explosion of the atomic bomb, the temple bell rings.

The shape of the temple-mausoleum is similar to a giant turtle, on whose shell there is a large white statue of the goddess of mercy Kannon. The sculpture, 18 meters high and weighing 35 tons, is made of aluminum alloy.

In the temple, a Foucault pendulum is suspended above the remains of 16,500 people killed during World War II. A 25-meter cable is located inside the statue.

The photo shows the interior of the temple. The cable of the Foucault pendulum emerges from a golden hole in the vault and descends behind a metal railing on the floor.

Photos: +

Basilica of San Petronio, Bologna
Perhaps the most suitable place to demonstrate Foucault’s pendulum was the Italian “city of sciences,” where the oldest university in Europe was founded (1088). The Cathedral of Bologna, dedicated to the patron saint of the city, Saint Bishop Petronius, was built over several centuries, starting in 1390. The basilica is striking in its size: the length of the building is 132 meters, the width is 60 meters, the height of the vaults is 45 meters.

The cathedral demonstrates not only Foucault’s experience (in the photograph in the background). Professor of astronomy at the University of Bologna Giovanni Domenico Cassini (1625-1712) in 1665 marked inside the cathedral, on the floor, a meridian 66.8 m long, on which one can observe the movement of the sun's ray through a hole in the roof of the temple and mark the days and months.

Photos: +

Church of St. John, Vilnius
The only Foucault pendulum in Lithuania is located in a Catholic church. Named after St. John the Baptist and St. John the Evangelist, the church was built in the 18th century according to the design of Johann Christoph Glaubitz (1700-1767). You can see the pendulum at the Science Museum by going up to the second floor of the 68-meter bell tower.

Photos: +

St. Sophia Cathedral, Vologda.
In Russia during Soviet times, the first display of Foucault's experience was prepared by the State Museum, the Union of Militant Atheists and the Society of Local History. The demonstration took place during the anti-Easter campaign of 1929 in the St. Sophia Cathedral of Vologda. An anti-religious exhibition was organized in the building, and the pendulum became one of its exhibits. The 18-meter long thread was suspended from metal connections in the interior. (Photograph 1917-1950)

St. Isaac's Cathedral, St. Petersburg
On Easter night from April 11 to 12, 1931, Jean Foucault's pendulum was demonstrated in St. Isaac's Cathedral. Thousands of spectators witnessed the scientific triumph. A bronze ball suspended from the dome was activated to visually demonstrate the rotation of the Earth. The length of the thread was 98 m - the longest in the entire history of the demonstration of the experiment.

The pendulum was removed in 1986, and the sculpture of a dove, a symbol of the Holy Spirit, was returned to the center of the dome, where the cable had previously been attached. Now Foucault’s pendulum is kept in the basement of St. Isaac’s Cathedral, in the memorial exhibition “To Be Remembered.”

The magazine “Museum World” (No. 10, 2016) says that back in 1901, in the Cathedral of St. Isaac of Dalmatia demonstrated the experience of Jean Foucault. But not in the center, under the dome, but in the vault of the side arch.

View of Decembrists Square and St. Isaac's Cathedral. 1930-1936

Exposition of the State Anti-Religious Museum in the building of St. Isaac's Cathedral. Leningrad, 1931
Schoolchildren at a model explaining the experiment with a Foucault pendulum. State Anti-Religious Museum. 1930s
Exposition of the State Anti-Religious Museum. 1930s A model that helped understand the essence of the experience.

In the same article, the location of the experiment is also indicated as being demolished during Soviet times. St. Andrew's Cathedral in Kronstadt. Experience in it was demonstrated at the end of the first decade of the 20th century.

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.

Adam Maloof of Princeton and Galen Halverson of Paul Sabatier University say they have found evidence of our planet rebalancing 800 million years ago. At this time, the geographic poles changed their position.

During an hour of observation, the plane of the pendulum's swing rotated through an angle of 11° clockwise. The plane of the pendulum completed a full revolution in 32 hours.

In the mid-20th century, a similar Foucault pendulum 98 m long was installed in Russia in St. Isaac's Cathedral in Leningrad. The public was incredibly surprised by the experiment with a matchbox, which was installed slightly away from the plane of rotation of the pendulum. After some time, the rod attached to the ball approached the box and knocked it down.

The plane of swing of the pendulum on the thread is maintained regardless of the rotation of the base to which the pendulum is suspended. If you place a Foucault pendulum at a pole, then the period of rotation of the pendulum there will be equal to the period of rotation of the Earth around its axis - 24 hours. The period of rotation of the pendulum axis depends on the latitude of the area. At the equator, the plane of the pendulum will not rotate - the period is equal to infinity.