If you think physics is a boring and unnecessary subject, then you are deeply mistaken. Our entertaining physics will tell you why a bird sitting on a power line does not die from electric shock, and a person caught in quicksand cannot drown in it. You will find out whether there really are no two identical snowflakes in nature and whether Einstein was a poor student at school.
10 interesting facts from the world of physics
Now we will answer questions that concern many people.
Why does a train driver back up before moving off?
This is all due to the force of static friction, under the influence of which the train cars are standing motionless. If the locomotive simply moves forward, it may not move the train. Therefore, it slightly pushes them back, reducing the static friction force to zero, and then accelerates them, but in a different direction.
Are there identical snowflakes?
Most sources claim that there are no identical snowflakes in nature, since their formation is influenced by several factors: air humidity and temperature, as well as the flight path of the snow. However, interesting physics says: it is possible to create two snowflakes of the same configuration.
This was experimentally confirmed by researcher Karl Libbrecht. Having created absolutely identical conditions in the laboratory, he obtained two externally identical snow crystals. True, it should be noted: their crystal lattice was still different.
Where in the Solar System are the largest reserves of water?
You'll never guess! The largest reservoir of water resources in our system is the Sun. The water there is in the form of steam. Its highest concentration is found in places we call “sunspots.” Scientists even calculated: in these areas the temperature is one and a half thousand degrees lower than in other areas of our hot star.
What invention of Pythagoras was created to combat alcoholism?
According to legend, Pythagoras, in order to limit the consumption of wine, made a mug that could be filled with an intoxicating drink only to a certain level. As soon as you exceeded the norm by even a drop, the entire contents of the mug flowed out. This invention is based on the law of communicating vessels. The curved channel in the center of the mug does not allow it to be filled to the brim, “riding” the container of all contents when the liquid level is above the bend of the channel.
Is it possible to turn water from a conductor into a dielectric?
Interesting physics says: it’s possible. Current conductors are not the water molecules themselves, but the salts contained in it, or rather their ions. If they are removed, the liquid will lose its ability to conduct electricity and become an insulator. In other words, distilled water is a dielectric.
How to survive a falling elevator?
Many people think that you need to jump when the cabin hits the ground. However, this opinion is incorrect, since it is impossible to predict when the landing will occur. Therefore, entertaining physics gives another advice: lie with your back on the floor of the elevator, trying to maximize the area of contact with it. In this case, the force of the impact will not be directed to one area of the body, but will be evenly distributed over the entire surface - this will significantly increase your chances of survival.
Why doesn't a bird sitting on a high voltage wire die from electric shock?
Birds' bodies do not conduct electricity well. By touching the wire with its paws, the bird creates a parallel connection, but since it is not the best conductor, charged particles do not move through it, but along the cable conductors. But if the bird comes into contact with a grounded object, it will die.
The mountains are closer to the heat source than the plains, but at their peaks it is much colder. Why?
This phenomenon has a very simple explanation. The transparent atmosphere allows the sun's rays to pass through without hindrance, without absorbing their energy. But the soil absorbs heat well. It is from this that the air then warms up. Moreover, the higher its density, the better it retains the thermal energy received from the earth. But high in the mountains the atmosphere becomes rarefied, and therefore less heat is retained in it.
Can quicksand suck you in?
There are often scenes in films where people “drown” in quicksand. In real life, says entertaining physics, this is impossible. You won’t be able to get out of a sandy swamp on your own, because to pull out just one leg, you’ll have to put in as much effort as it takes to lift a medium-weight passenger car. But you won’t be able to drown either, since you’re dealing with a non-Newtonian fluid.
Rescuers advise in such cases not to make sudden movements, lie down with your back down, spread your arms to the sides and wait for help.
Does nothing exist in nature, watch the video:
Amazing incidents from the lives of famous physicists
Outstanding scientists are mostly fanatics of their field, capable of anything for the sake of science. For example, Isaac Newton, trying to explain the mechanism of perception of light by the human eye, was not afraid to experiment on himself. He inserted a thin ivory probe into the eye while pressing on the back of the eyeball. As a result, the scientist saw rainbow circles in front of him and thus proved: the world we see is nothing more than the result of light pressure on the retina.
Russian physicist Vasily Petrov, who lived in the early 19th century and studied electricity, cut off the top layer of skin on his fingers to increase their sensitivity. At that time, there were no ammeters and voltmeters that made it possible to measure the strength and power of current, and the scientist had to do it by touch.
The reporter asked A. Einstein whether he writes down his great thoughts, and if he writes them down, where - in a notebook, a notebook or a special card index. Einstein looked at the reporter’s voluminous notebook and said: “My dear! Real thoughts come to mind so rarely that it is not difficult to remember them.”
But the Frenchman Jean-Antoine Nollet preferred to experiment on others. Conducting an experiment in the mid-18th century to calculate the speed of transmission of electric current, he connected 200 monks with metal wires and passed voltage through them. All participants in the experiment twitched almost simultaneously, and Nolle concluded: the current runs through the wires very, very quickly.
Almost every schoolchild knows the story that the great Einstein was a poor student in his childhood. However, in fact, Albert studied very well, and his knowledge of mathematics was much deeper than what the school curriculum required.
When the young talent tried to enter the Higher Polytechnic School, he scored the highest score in the core subjects - mathematics and physics, but in other disciplines he had a slight deficiency. On this basis he was refused admission. The next year, Albert showed excellent results in all subjects, and at the age of 17 he became a student.
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Most people are sure that physics is boring and has little to do with life. Even knowing that many phenomena in it have a scientific explanation, they consider understanding the nature of each of them accessible only to specialists.
In fact, physics is not only equations, formulas and diagrams. And the people studying it are by no means creatures covered in book dust. and scientists involved in this science are proof of this.
Is physics ever interesting?
Everything that exists on Earth and beyond is subject to physical laws. People don't think about it, but they use it in everyday life. For example, everyone knows that you should not swim in a river during a thunderstorm, because you need to be afraid of being struck by lightning. But it is also dangerous in an open, dry space. What's scary about water? And the fact that it conducts electricity perfectly, but only thanks to the impurities it contains, ions of mineral salts. Water molecules themselves do not perceive current, but ignorant people have no idea about this. Although it is unlikely that knowledge of such interesting facts about physics would encourage them to fill swimming pools with distilled liquid and swim in a thunderstorm.
Anyone has ridden in an elevator at least once in their life. And many people thought about what to do if he started falling from a height. Most would conclude that there was no chance of survival under such circumstances. Or that at the moment of impact you need to jump. In fact, it is impossible to calculate this time. But if you make sure that the impact force falls on as large a surface area of the body as possible, perhaps everything will work out. That is, you simply need to lie on the floor. As seen, interesting facts about physics can save lives. 
Sometimes the laws of science look like miracles. For example, when opening a bottle sealed with a cork against a wall. If you cover the latter with folded paper and hit it with the bottom of the vessel at a strictly 90-degree angle, the plug will come out so much that it can be removed without a corkscrew. This is possible due to a sharp change in the speed of liquid flow in the bottle due to a collision with a wall. The impact falls right on the traffic jam.
Why does the train go backwards before moving forward?
If the driver of a heavy freight train tries to start moving it sharply forward, the train may not move, since the total static friction force acting from the rails on the wheels of the cars will exceed the sliding force of the driving wheels of the locomotive. Often the driver must first back up to release the tension on the couplers. And only then drive forward, setting the carriages in motion one after another.
Which physicist failed to win the Nobel Prize despite being nominated 84 times?
German physicist Arnold Sommerfeld, noted for his achievements in quantum theory, electronic theory, electrodynamics and many other scientific fields, was nominated for the Nobel Prize 84 times from 1917 to 1951, but never received it. Sommerfeld still holds the record for this indicator. But seven of his students became Nobel laureates: Werner Heisenberg, Wolfgang Pauli, Peter Debye, Hans Albrecht Bethe, Linus Pauling, Isidor Isaac Rabi and Max von Laue.
Can two identical snowflakes exist?
The formation of snowflakes depends on the temperature and humidity of the air inside the ice cloud, as well as the trajectory of their movement, in which the outlines of their rays constantly change. Therefore, many sources claim that identical snowflakes do not exist in nature. However, targeted searches by the US Center for Atmospheric Research in 1988 refuted this hypothesis - specialists managed to discover two identical snow crystals. And in 2015, physicist Kenneth Libbrecht obtained them in the laboratory, providing them with identical initial growth conditions. It is worth noting that in both cases, despite the external similarity, the atomic structure of the crystals was still different.
What physical law helped to convict stock exchange players of illegal insider trading?
In 2013, US authorities began investigating some players on the Chicago Stock Exchange. They were caught insider trading when they began trading futures on completely different terms than before within 2 milliseconds of a major announcement from the Federal Reserve. However, a simple calculation showed that it would take 7 milliseconds for information to travel between Washington and Chicago even at the speed of light.
Under what conditions can a liquid flow, “ignoring” the forces of friction and gravity?
In a state of superfluidity, a liquid has zero viscosity and can move with the effect of ignoring the forces of friction and attraction. This phenomenon has been best studied using the example of liquid helium at temperatures close to absolute zero. If you place such a liquid in a container, providing a microscopic layer of helium on the walls, it will rise along them and flow out over the edge.
Which famous scientist liked to work on his theories in a strip club?
American physicist Richard Feynman, Nobel Prize winner, sometimes went to work in a strip club. When tired from calculating yet another theory, he looked at naked girls, which helped clear his head.
What famous physical theory received its name from its critic?
The term “Big Bang” to characterize the early development of the Universe was first used by British astronomer Fred Hoyle in a lecture that was devoted to criticism of this model. Nevertheless, the term caught on, coming into use among supporters of the Big Bang theory. By the way, from English “Big Bang” is more appropriately translated as “Big Cotton”, which more accurately conveys the negative connotation implied by Hoyle.
In what region of space can a person see his back without the help of instruments?
Light consists of elementary particles of photons, which have no mass or charge. Near black holes there are so-called photon spheres - areas where gravity is so strong that photons begin to rotate in orbits. If an observer falls into the photon sphere, he can theoretically see his own back.
Which scientists begged Kustodiev to paint their portrait just when they were planning to become famous?
In 1921, two young scientists approached the artist Boris Kustodiev with a request to paint their portrait. Their argument was that Kustodiev only paints celebrities, and they are sure that they will also become famous, even if they are not particularly known to anyone now. These scientists were Pyotr Kapitsa and Nikolai Semenov, future Nobel laureates in physics and chemistry, respectively. As a fee, they gave the artist a bag of millet and a rooster received for repairing the mill.
Where are the largest reserves of water in the solar system?
The largest reserves of water in the Solar System are, strange as it may seem at first glance, in the Sun. Water molecules in the form of vapor are concentrated in sunspots, the temperature of which is one and a half thousand degrees lower than in the surrounding areas, as well as in the region of temperature minimum - a narrow layer under the surface of the star.
What special state of matter is found in a chicken eye?
There is a special state of matter called “disordered superhomogeneity,” in which the substance has the properties of a crystal and a liquid at the same time. It was first discovered by physicists in liquid helium and simple plasmas, but recently biologists also encountered it when studying the chicken eye. Like other diurnal birds, chickens have five types of photoreceptors: red, blue, green, violet and those responsible for the perception of light. All of them are located on the retina in one layer, at first glance, randomly, but upon detailed study of the patterns, it turned out that around each cone there is a so-called forbidden zone, in which the appearance of other cones of the same type is excluded. As a result, the system cannot take on a single ordered form, but strives to be as homogeneous as possible.
Under what conditions does unwinding a roll of tape produce x-rays?
When a roll of tape is unwound in a vacuum, both visible light and x-rays are produced. Scientists believe that the reason for this is an effect similar to triboluminescence - the appearance of electromagnetic radiation when asymmetric bonds in a crystal are destroyed. However, the adhesive mass does not have a crystalline structure, so another theoretical model is required to explain the glow created by the tape. The power of the emerging X-ray radiation is sufficient to obtain images of body parts, but this is only in a vacuum, and unwinding the tape in the air is absolutely safe.
Under what conditions in water can sound be converted into light?
In an aquatic environment, sonoluminescence can be observed, that is, the transformation of sound into light. To do this, you need to lower a resonator into the water, creating a standing spherical ultrasonic wave. In the rarefaction phase of the wave, due to the very low pressure, a cavitation bubble appears, which grows for some time, and then quickly collapses in the compression phase. At this moment, a flash of light appears in the center of the bubble, and the observer sees a constant bluish glow, as the bubbles originate and collapse at a very high speed. According to the prevailing point of view in scientific circles, this radiation is of thermal nature.
Is Newton's discovery of the theory of gravity related to the falling of an apple?
Popular legend attributes Newton's discovery of the theory of gravity to an incident where an apple fell on his head. However, if a blow to the head can really be considered only a caricatured myth, the very fact of seeing an apple falling is described by at least two different authors. William Stukeley's biography of Newton tells of their conversation in an apple orchard in 1726 over a cup of tea - when the famous scientist recalled his thoughts about gravity, which arose in a similar environment. Newton's assistant John Conduit clarifies in his book that the incident with the falling apple took place in 1666, when the scientist was vacationing on his mother's estate. It is worth noting that the book “Mathematical Principles of Natural Philosophy,” in which the law of universal gravitation is proved, was published not immediately after this, but twenty years later.
What mug was invented by Pythagoras, wanting to protect people from excessive passion for wine?
The so-called Pythagorean mug is very popular in Greek souvenir shops. This is a vessel into which you can pour liquid only up to a certain level, but if you pour it higher, everything will leak out. This effect is achieved using a doubly curved channel in the center of the mug, one end of which is open at the bottom and the other goes inward. The pouring of liquid occurs in accordance with Pascal's law of communicating vessels. According to legend, Pythagoras invented this mug for moderate consumption of wine and punishment for those who are too greedy.
What causes the faint glow of water at depths where sunlight does not reach?
At depths of several hundred meters and beyond, there is no complete darkness, as one might assume. Sunlight does not reach here, but isotopes of calcium and other elements dissolved in water emit fast electrons, which cause a faint glow due to the Vavilov-Cherenkov effect. Apparently, this circumstance is the reason why deep-sea fish did not lose their eyes during evolution.
Which father and son received Nobel Prizes for different studies of the same particles?
The electron as a particle was discovered in 1897 by the English physicist Joseph John Thomson. Nine years later he was given the Nobel Prize with the wording “for research into the conductivity of electricity by gases.” His son, George Paget Thomson, discovered the wave properties of the electron in 1927 and subsequently also received a Nobel Prize “for the experimental discovery of electron diffraction by crystals.”
How can icicles appear under thick sea ice and reach the bottom of the sea?
Sometimes large icicles, similar to stalactites, can appear under the sea ice. When ice forms, there is no salt left in its crystal lattice, and at some points, downdrafts of very cold and very salty water form. Under certain conditions, a layer of ice begins to grow downward around such a flow. If the sea is shallow in a given place, the icicle reaches the bottom and continues to grow in some horizontal direction.
How can water be used as a dielectric?
Many people know that water is a good conductor of electricity - that is why, for example, you should not swim during a thunderstorm, as you can become a victim of lightning striking a pond. However, it is not the water molecules themselves that conduct the current, but the impurities contained in it, ions of various mineral salts. Distilled water, which contains almost no salts, is a dielectric.
Which planet has an almost regular hexagon at its north pole?
At the north pole of Saturn there is a vortex of clouds in the shape of an almost regular hexagon. There is no strict scientific explanation for this phenomenon, but scientists at Oxford University were able to create similar vortices in a laboratory experiment. Small rings were lowered into a bottle of water standing on a rotating table, which rotated even faster. The resulting vortices created fluid flows of various shapes - not only hexagonal, but also square, triangular and oval.
Which scientist measured the speed of electric current on living people connected in a circuit?
The speed of electric current is almost equal to the speed of light. In 1746, when this was not yet known, the French priest and physicist Jean-Antoine Nollet wanted to measure the speed of current experimentally. He placed 200 monks, connected to each other by iron wires, in a circle over one and a half kilometers long, and then discharged a battery of Leyden jars, invented a year earlier, into this circuit. All the monks reacted to the current in an instant, which convinced Nolle of the very high value of the desired value.
How can you use a wall and a newspaper to open a bottle of wine without a corkscrew?
To open a bottle of wine without a corkscrew, you will need a hard surface, such as a wall, as well as a softening object - a book, newspaper or just a shoe. Leaning the newspaper against the wall, you need to take the bottle and hit it with the bottom strictly perpendicular to the wall one or more times until the cork comes out far enough to remove the remainder by hand. This phenomenon is explained by the fact that during a collision, the speed of the liquid flow inside the bottle changes sharply, causing a water hammer to occur on the stopper. It is worth noting that if handled improperly, the bottle may break, so it is better to carry out the experiment by wrapping it in a towel.
Where and when did a spontaneous natural nuclear reactor operate?
On the territory of the Oklo uranium deposit in Gabon, ore bodies were discovered in which a spontaneous chain reaction of fission of uranium nuclei occurred almost 2 billion years ago. In other words, there was a natural nuclear reactor here, and it worked for several hundred thousand years. This discovery was made in 1972, when a mass spectrometric analysis of rock was carried out at a French enrichment plant in Gabon and revealed a lower than usual concentration of the uranium isotope 235U, which indicated the presence of spent nuclear fuel.
What grades did Einstein get in mathematics at school?
In many sources, often with the purpose of encouraging poorly performing students, there is a statement that Einstein failed mathematics at school or, moreover, generally studied very poorly in all subjects. In fact, everything was not like that: Albert began to show talent in mathematics at an early age and knew it far beyond the school curriculum. Later, Einstein was unable to enter the Swiss Higher Polytechnic School of Zurich, showing the highest results in physics and mathematics, but not achieving the required number of points in other disciplines. Having mastered these subjects, a year later, at the age of 17, he became a student at this institution.
How can you turn headphones into a microphone?
If you connect regular headphones to the microphone input, they can be used as a microphone. In a simplified way, the design of the headphones and microphone is the same: the membrane is connected to a coil of wire located in the magnetic field of a permanent magnet. In headphones, during normal use, the current supplied to the coil is converted into vibrations of the membrane, and in a microphone, vice versa.
What can you do to maximize your chances of surviving a falling elevator?
If you find yourself in a falling elevator, the best strategy to increase your chances of survival is to lie on your back and try to take up as much floor space as possible. In this case, the impact force will be distributed as much as possible over the surface of the body. A common belief is that you just need to jump during the impact, but this is a misconception - it is unlikely that anyone is able to accurately guess the time of the collision and jump at the same speed as the elevator falls.
What explains the motionlessness of some clouds even in very strong winds?
In mountainous areas you can see clouds that can hang motionless even in very strong winds - they are called lenticular. This is explained by the fact that the wind moves air masses in certain currents, or waves, flowing around various obstacles. Lenticular clouds form on the crests of such waves or between two layers of air. Their stability is due to the simultaneous processes of condensation of water vapor at the height of the dew point and evaporation of water droplets during downward air movement. These clouds are usually round in shape, which is why they are often mistaken for UFOs.
Why are human eyes blue and green even though they have no such pigments?
There are no blue or green pigments in the iris of the human eye. The only coloring pigment in the eye is melanin: at certain concentrations, the eye color changes from light brown to almost black. However, with a low melanin content, short waves of the light spectrum are not absorbed by the membrane, but are reflected, as a result of which we record blue, cyan, green or gray eye color. This effect is due to Rayleigh scattering of light, which similarly explains the blue or gray color of the sky we see.
Which of the inhabitants of our planet holds the record for time travel?
Russian cosmonaut Gennady Padalka spent a total of 878 days in orbit, which is a world record. At the same time, he can be considered the owner of another record - the longest time travel among the inhabitants of our planet. According to the theory of relativity, the greater the speed at which an object moves, the more time slows down for it. It is calculated that thanks to space flights, Padalka is 1/45 of a second younger than if he had remained on Earth all the time. In other words, the astronaut returned from orbit to a time point 1/45 of a second later than expected under normal conditions.
Why don't mosquitoes die in the rain?
The mass of a raindrop is many times greater than the mass of a mosquito. This factor, as well as the hairs on the entire surface of the body, lead to very little transfer of impulse from the drop to the mosquito, which gives the insects the ability to survive in the rain. Another important factor is that the collision occurs in the air and not on a fixed surface. When a drop hits a mosquito, two scenarios are possible: if the impact is off-center, the insect rotates a little and flies further; otherwise, the drop briefly carries the mosquito along with it, but it quickly frees itself.
What familiar object helps you look through opaque frosted glass?
To look through glass with a matte surface, just stick a piece of transparent tape on it. Due to the unevenness of the frosted glass, the light is scattered, but the adhesive side of the tape smoothes out these unevenness, and as a result, the light passes through as if through ordinary glass. It should be added that if the surface is matte on both sides, this trick will no longer work.
To what temperature below zero can water remain liquid?
In its normal state, water begins to turn into ice at a temperature of 0 °C. The process of water freezing occurs near crystallization centers, which form near places of microscopic disturbances. However, if these disturbances are removed, water can remain liquid down to −43 °C, a state called supercooled water. One commercial application of this effect is introduced by beverage manufacturers. Special batches of soda are delivered with supercooled water, and when the bottle is opened, a mixture of drink and ice immediately forms inside.
Under what conditions does an inverted rainbow occur?
There is an optical phenomenon that can be called an inverted rainbow, although it happens very rarely. Such a rainbow appears only when several conditions are met. In the sky at an altitude of 7-8 km there should be a thin curtain of cirrus clouds consisting of ice crystals, and sunlight should fall on them at a certain angle in order to be decomposed into a spectrum and reflected into the atmosphere. The colors in an upside down rainbow are also arranged in reverse: purple is at the top and red is at the bottom.
Why are the mountains colder than the lowlands, even though they are closer to the sun?
The sun does not heat the earth's air directly. Its radiation passes through the layers of the atmosphere and is absorbed by land and water on the surface of the planet, and only then the air receives thermal energy from them. Therefore, although the mountains are closer to the sun, they are colder than on the plains, since on average, with every kilometer rise, the temperature decreases by 6 °C due to the adiabatic expansion of air. But even at the highest altitudes there can be valleys that, due to the special topography and the reflection of the sun's rays from the snow, can be well heated. For example, in the so-called Western Circus, which is located on one of the routes to the peak of Everest at an altitude of more than 6,000 meters, on sunny, windless days the temperature can rise to 35 °C.
What is being studied in the longest continuous laboratory experiment in history?
In 1927, Thomas Parnell, a professor at the Australian University of Queensland, conducted an experiment to demonstrate to students the liquid properties of bitumen tar, a substance that is solid in its normal state. After heating the resin, he poured it into a sealed glass funnel and closed the top, and three years later he cut off the bottom of the funnel, allowing droplets to form. The first drop fell in 1938, the next ones fell at approximately the same interval - a total of 9 drops have been recorded to date. This experiment is considered the longest continuous laboratory experiment in history.
In what environment can light be stopped completely?
The maximum possible speed of particles is called the speed of light in a vacuum and is a constant. However, outside a vacuum, light can travel at speeds much lower than this constant value. There is a special state of matter, the Bose-Einstein condensate, in which light slows down most strongly. Experimentally, light was even completely stopped in the Bose-Einstein condensate of rubidium by the formation of stationary, non-shifting solitons.
Why do the bubbles in Guinness beer move down, not up?
In Guinness beer, you can clearly see how the bubbles go down the walls of the glass instead of going up. This is explained by the fact that in the central part of the glass the bubbles quickly rise, pushing the liquid down at the edges with stronger viscous friction. But this effect is characteristic not only of Guinness, but of any liquid in general, it’s just more noticeable in this beer. This is primarily due to the fact that instead of carbon dioxide, Guinness is filled with nitrogen, which is less soluble in water. Secondly, light bubbles are simply more visible against the background of very dark beer.
Which scientist cut off the skin from his fingers and for what purpose?
The Russian scientist Vasily Petrov, who was the first in the world to describe the phenomenon of an electric arc in 1802, did not spare himself when conducting experiments. At that time there were no instruments such as an ammeter or a voltmeter, and Petrov checked the quality of the batteries by the sensation of electric current in his fingers. And in order to feel very weak currents, the scientist specially cut off the top layer of skin from the tips of his fingers.
Can a person drown in quicksand?
To pull your foot out of quicksand at a speed of 0.1 m/s, you need to apply a force similar to the force of lifting a medium-sized car. However, being a non-Newtonian fluid, quicksand cannot swallow a person entirely. The death of those stuck is caused by other causes, such as dehydration, high tide or solar radiation. If you get into quicksand, it is better not to make sudden movements, but try to lie on your back and, with your arms outstretched, wait for help.
What physical effect has been proven in practice by musicians who played the same note for two days in a row?
Austrian physicist Christian Doppler theoretically substantiated in 1842 that the frequency of vibrations perceived by an observer depends on the speed and direction of movement of the wave source and the observer relative to each other. Three years later, the Dutch meteorologist Christopher Bays-Ballot set out to prove this statement in practice. He hired a steam locomotive with a platform for a couple of days, placing two trumpeters on it holding the note G, and placed several musicians with absolute pitch on the platform. In the second stage of the experiment, the listeners moved while the musicians played motionless. All this time, observers noted that they heard different notes, as a result of which the truth of the Doppler effect was confirmed.
What human invention was the first to break the sound barrier?
The characteristic click after swinging the whip is due to the fact that its tip moves at supersonic speed. A similar effect occurs when an airplane flies at a speed greater than the speed of sound: from the shock wave it creates, the observer can hear a loud sound, similar to an explosion. However, it is the whip that can be recognized as the first human invention to overcome the sound barrier.
Why doesn't a bird sitting on a wire die from electric shock?
A bird sitting on a high-voltage power line does not suffer from current, because its body is a poor conductor of current. Where the bird's paws touch the wire, a parallel connection is created, and since the wire conducts electricity much better, a very small current flows through the bird itself, which cannot cause harm. However, as soon as the bird on the wire touches another grounded object, for example, a metal part of a support, it immediately dies, because then the air resistance is too great compared to the resistance of the body, and all the current flows through the bird.
What kind of memory can metal alloys have?
Some metal alloys, such as nitinol (55% nickel and 45% titanium), have a shape memory effect. It lies in the fact that a deformed product made of such material, when heated to a certain temperature, returns to its original shape. This is due to the fact that these alloys have a special internal structure called martensite, which has the property of thermoelasticity. In the deformed parts of the structure, internal stresses arise, which tend to return the structure to its original state. Shape memory materials have found wide application in manufacturing - for example, for connecting bushings, which compress at very low temperatures and straighten at room temperature, forming a connection much more reliable than welding.
How did the Pauli effect prevent Pauli's hoax?
Scientists call the Pauli effect the failure of instruments and the unplanned course of experiments when famous theoretical physicists appear - for example, Nobel laureate Wolfgang Pauli. One day they decided to play a prank on him by connecting the wall clock in the hall where he was to give a lecture with the front door using a relay so that when the door was opened, the clock would stop. However, this did not happen - when Pauli entered, the relay suddenly failed.
What colored noises exist besides white noise?
The concept of “white noise” is widely known - this is what they say about a signal with uniform spectral density at all frequencies and dispersion equal to infinity. An example of white noise is the sound of a waterfall. However, in addition to white, there are a large number of other colored noises. Pink noise is a signal whose density is inversely proportional to frequency, and red noise has a density inversely proportional to the square of the frequency - they are perceived by ear as “warmer” than white noise. There are also concepts of blue, violet, gray noise and many others.
Which elementary particles are named after the sounds of ducks?
Murray Gell-Mann, who hypothesized that hadrons were made of even smaller particles, decided to call these particles the sound that ducks make. James Joyce’s novel “Finnegans Wake” helped him formulate this sound into a suitable word, namely the line: “Three quarks for Muster Mark!” Hence the particles received the name quarks, although it is not at all clear what meaning this previously non-existent word had for Joyce.
Why is the sky blue during the day and red during sunset?
Short-wave components of the solar spectrum are scattered in the air more strongly than long-wave components. This is why we see the sky as blue - because blue is at the short wavelength end of the visible spectrum. For a similar reason, during sunset or dawn, the sky on the horizon turns red. At this time, the light travels tangentially to the earth's surface, and its path through the atmosphere is much longer, as a result of which a significant part of the blue and green color leaves direct sunlight due to scattering.
What is the difference between the mechanism of lapping water in cats and dogs?
During the process of lapping, cats do not plunge their tongue into the water, but, lightly touching the surface with the curved tip, immediately pull it back up. In this case, a column of liquid is formed due to the subtle balance of gravity, which pulls the water down, and the force of inertia, which forces the water to continue moving upward. Dogs use a similar lapping mechanism - although it may seem to an observer that the dog is scooping up liquid with its tongue folded into a paddle, x-ray analysis has shown that this “spatula” unfolds inside the mouth, and the column of water created by the dog is similar to that of a cat.
Who holds both the Nobel and Ig Nobel Prizes?
Dutch physicist of Russian origin Andre Geim received the Nobel Prize in 2010 for experiments that helped study the properties of graphene. And 10 years earlier, he received an ironic Ig Nobel Prize for an experiment on diamagnetic levitation of frogs. Thus, Game became the first person in the world to hold both the Nobel and Ig Nobel Prizes.
Why are ordinary city streets dangerous for racing cars?
When a racing car is driven on a track, very low pressure can build up between the bottom of the car and the road, enough to lift a manhole cover. This happened, for example, in Montreal in 1990 at the sports prototype race - a lid raised by one of the cars hit the car behind it, which started a fire and the race was stopped. Therefore, now in all races of cars on city streets, the covers are welded to the rim of the hatch.
Why did Newton throw a foreign object into his eye?
Isaac Newton was interested in many aspects of physics and other sciences and was not afraid to perform some experiments on himself. He tested his guess that we see the world around us due to the pressure of light on the retina of the eye in the following way: he cut out a thin curved probe from ivory, inserted it into his eye and pressed on the back side of the eyeball. The emerging colored flashes and circles confirmed his hypothesis.
Why is the unit of measurement for both temperature and strength of alcoholic drinks called the same - degree?
In the 17th and 18th centuries, there was a physical theory about caloric - weightless matter found in bodies and causing thermal phenomena. According to this theory, more heated bodies contain more caloric than less heated ones, therefore temperature was defined as the strength of the mixture of body matter and caloric. That is why the unit of measurement for both temperature and strength of alcoholic drinks is called the same - degree.
Why were two German-American satellites named Tom and Jerry?
In 2002, Germany, together with the United States, launched a system of two space satellites to measure Earth's gravity called GRACE. They fly in the same orbit at an altitude of about 450 kilometers, one after another, with an interval of 220 kilometers. When the first satellite approaches an area of high gravity, such as a large mountain range, it accelerates and moves away from the second satellite. And after some time, the second device flies here, also accelerates and thereby restores the original distance. For such a game of “catch-up,” the companions were given the names Tom and Jerry.
Why can't the American SR-71 Blackbird spy plane be fully refueled on the ground?
The American reconnaissance aircraft SR-71 Blackbird at normal temperatures has gaps in its skin. During flight, the skin heats up due to friction with the air, and the gaps disappear, and the fuel cools the skin. But in its normal state on the ground, the plane loses, albeit in small quantities, fuel through these cracks. For this reason (and also to reduce take-off speed by saving weight), first only a small amount of fuel is filled into the plane, and refueling occurs in the air.
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Issue 6In the sixth physics video lesson from the Academy of Entertaining Sciences, Professor Quark will talk about the law of gravity, as well as another law - the law of universal attraction. These laws influence many phenomena in the world, for example, the shape of our planet, the movement and interaction of bodies. You will learn about the manifestations of these forces and what they depend on by watching a physics video lesson from the Academy of Entertaining Sciences.
Law of gravity
The law of gravity acts on all bodies located on our planet. We owe the discovery of this law to Sir Isaac Newton, a world famous English scientist who lived in the 17th century. According to legend, the idea of the law of gravity came to Newton's mind when he saw an apple falling from a branch. The law of gravity is a special case of another law - the law of the universal attraction of objects to each other. According to this law, everything is attracted to everyone. The heavier a thing is, the more strongly it attracts surrounding objects. Also, the force of attraction depends on the distance between objects. But why do some objects fall to the ground faster than others? It's about air resistance. So, a sheet of paper falls slower than a small pebble because its surface rests on the air. Oddly enough, the force of gravity is the same for both light objects and heavy ones. Thanks to the law of universal gravitation, people anywhere in the world walk on their feet, and not upside down. After all, the force of gravity acts in the direction of the center of the Earth and it does not matter at what point on the earth’s surface we are. By the way, the Earth, other planets and stars owe their shape to the force of gravity. This force gives them the shape of a ball, because each planet has a center to which all the matter of which it consists is attracted. Moreover, it is attracted with the same force. This force depends on the strength of the gravitational field of the planet or star. So, on the Moon the force of gravity is less and people can move along its surface in huge jumps. This is because the Moon's gravitational field is much weaker than Earth's. The strength of the gravitational field depends on the mass of the planet or star: the greater the mass, the stronger the gravitational field. Thanks to the force of gravity, the planets take their places, rotating in orbits around the Sun.
If you think physics is boring, then this article is for you. We will tell you fun facts that will help you take a fresh look at your least favorite subject.
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No. 1: why is the Sun red in the evenings?
Actually, the sun's light is white. White light, in its spectral decomposition, is the sum of all the colors of the rainbow. In the evening and morning, the rays pass through the low surface and dense layers of the atmosphere. Dust particles and air molecules thus act as a red filter, best transmitting the red component of the spectrum.
#2: Where do atoms come from?
When the Universe formed, there were no atoms. There were only elementary particles, and even then not all of them. The atoms of the elements of almost the entire periodic table were formed during nuclear reactions in the interior of stars, when lighter nuclei turn into heavier ones. We ourselves are made up of atoms formed in deep space.
No. 3: How much “dark” matter is there in the world?
We live in a material world and everything that is around is matter. You can touch it, sell it, buy it, you can build something. But there is not only matter in the world, but also dark matter. It does not emit electromagnetic radiation and does not interact with it.
Dark matter, for obvious reasons, has not been touched or seen by anyone. Scientists decided that it exists by observing some indirect signs. It is believed that dark matter makes up about 22% of the Universe. For comparison: the good old matter we are used to takes up only 5%.
No. 4: what is the temperature of lightning?
And it’s clear that it’s very high. According to science, it can reach 25,000 degrees Celsius. This is many times more than on the surface of the Sun (there are only about 5000). We strongly do not recommend trying to check what the temperature of the lightning is. There are specially trained people in the world for this.
Eat! Considering the scale of the Universe, the probability of this had previously been assessed quite high. But it was only relatively recently that people began to discover exoplanets.
Exoplanets orbit their stars in what is called the “life zone.” More than 3,500 exoplanets are now known, and they are being discovered more and more often.
#6: How old is the Earth?
The earth is about four billion years old. In the context of this, one fact is interesting: the largest unit of time is the kalpa. Kalpa (otherwise the day of Brahma) is a concept from Hinduism. According to him, day gives way to night, equal in duration. At the same time, the length of Brahma’s day coincides with the age of the Earth to within 5%.
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#7: Where do the aurora come from?
The polar or northern lights are the result of the interaction of the solar wind (cosmic radiation) with the upper layers of the Earth's atmosphere.
Charged particles coming from space collide with atoms in the atmosphere, causing them to become excited and emit light. This phenomenon is observed at the poles, as the Earth's magnetic field "captures" particles, protecting the planet from "bombardment" by cosmic rays.
#8: Is it true that the water in the sink swirls in different directions in the northern and southern hemispheres?
Actually this is not true. Indeed, there is a Coriolis force acting on the flow of fluid in a rotating reference frame. On the scale of the Earth, the effect of this force is so small that it is possible to observe the swirling of water as it flows in different directions only under very carefully selected conditions.
No. 9: how is water different from other substances?
One of the fundamental properties of water is its density in solid and liquid states. Thus, ice is always lighter than liquid water, so it is always on the surface and does not sink. Also, hot water freezes faster than cold water. This paradox, called the Mpemba effect, has not yet been fully explained.
#10: How does speed affect time?
The faster an object moves, the slower time will pass for it. Here we can recall the paradox of twins, one of whom traveled on an ultra-fast spaceship, and the second remained on earth. When the space traveler returned home, he found his brother an old man. The answer to the question of why this happens is given by the theory of relativity and relativistic mechanics.
We hope our 10 facts about physics helped convince us that these are not just boring formulas, but the whole world around us.
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