Physics translated from ancient Greek - “nature”. Physics is a field of natural science, a science that studies the most fundamental patterns that determine the general structure and evolution of the material world. Being one of the three pillars on which the modern world order system is based, physics is the science of nature in the broadest sense of the word! In addition to the fact that she studies the material and energy parameters of the organization of the universe, she also sets herself the task of explaining and logical justification of the fundamental interactions in nature that control the movement of matter.
In fact, it is physics that is the main engine of technological progress of humanity as a whole. Without detracting from the merits of other branches of scientific thought, I would still like to mention such greatest geniuses of the human race as Isaac Newton, Albert Einstein, Nikola Tesla, etc., etc. It was physicists who allowed humanity to take more than just a step in the direction of its technical development , but take a giant leap!!!
Over the past 100 years, man has mastered the energy of the atom, introduced electricity everywhere into all spheres of life, created something without which you could not read these lines - the Internet, conquered the air, water, and began exploring the underwater space of our planet. He created super-strong materials with unprecedented properties, computers that perform billions of logical operations per second, penetrated the endless depths of the human brain, saw the smallest inhabitants of our planet, which we now call viruses, learned to artificially grow and transplant human organs and escaped beyond the atmosphere of planet earth. It’s impossible to count everything. But I think this is enough to fully understand what physical science is.
The question may arise: why do you need physics? Let us answer it again with the same question: why do centipedes need legs, birds need wings, and plants need the sun? That's right - yes, because they can't do without all this!!! :) We need physics today more than ever before. After all, you use the laws of physics every day, in your everyday life... - when you cook food, watch TV or just soak in the bath. The laws of Archimedes, the laws used in optics, or the physical laws from the section of hydro-gas dynamics have become something so commonplace for us that we simply don’t pay attention to them anymore, but in vain... Physics is, first of all, the opportunity for a person to understand the world around him as deeply as possible, to streamline the system of his worldview and to realize himself as an integral part of it!
Physical science is comprehensive in its desire to cover as much as possible and describe in as much detail as possible what falls into the field of view of its apologists, and therefore can rightfully claim the honorary title of Queen of Sciences!
In school physics lessons, teachers always say that physical phenomena are everywhere in our lives. Only we often forget about this. Meanwhile, amazing things are nearby! Don't think that you need anything extravagant to organize physical experiments at home. And here's some proof for you ;)
Magnetic pencil
What needs to be prepared?
- Battery.
- Thick pencil.
- Insulated copper wire with a diameter of 0.2–0.3 mm and a length of several meters (the longer, the better).
- Scotch.
Conducting the experiment
Wind the wire tightly, turn to turn, around the pencil, 1 cm short of its edges. When one row ends, wind another on top in the opposite direction. And so on until all the wire runs out. Don’t forget to leave two ends of the wire, 8–10 cm each, free. To prevent the turns from unwinding after winding, secure them with tape. Strip the free ends of the wire and connect them to the battery contacts.
What happened?
It turned out to be a magnet! Try bringing small iron objects to it - a paper clip, a hairpin. They are attracted!
Lord of Water
What needs to be prepared?
- A plexiglass stick (for example, a student’s ruler or a regular plastic comb).
- A dry cloth made of silk or wool (for example, a wool sweater).
Conducting the experiment
Open the tap so that a thin stream of water flows. Rub the stick or comb vigorously on the prepared cloth. Quickly bring the stick closer to the stream of water without touching it.
What will happen?
The stream of water will bend in an arc, being attracted to the stick. Try the same thing with two sticks and see what happens.
Top
What needs to be prepared?
- Paper, needle and eraser.
- A stick and a dry woolen cloth from previous experience.
Conducting the experiment
You can control more than just water! Cut a strip of paper 1–2 cm wide and 10–15 cm long, bend it along the edges and in the middle, as shown in the picture. Insert the sharp end of the needle into the eraser. Balance the top workpiece on the needle. Prepare a “magic wand”, rub it on a dry cloth and bring it to one of the ends of the paper strip from the side or top without touching it.
What will happen?
The strip will swing up and down like a swing, or spin like a carousel. And if you can cut a butterfly out of thin paper, the experience will be even more interesting.
Ice and fire
(the experiment is carried out on a sunny day)
What needs to be prepared?
- A small cup with a round bottom.
- A piece of dry paper.
Conducting the experiment
Pour water into a cup and place it in the freezer. When the water turns to ice, remove the cup and place it in a container of hot water. After some time, the ice will separate from the cup. Now go out onto the balcony, place a piece of paper on the stone floor of the balcony. Use a piece of ice to focus the sun on a piece of paper.
What will happen?
The paper should be charred, because it’s not just ice in your hands anymore... Did you guess that you made a magnifying glass?
Wrong mirror
What needs to be prepared?
- A transparent jar with a tight-fitting lid.
- Mirror.
Conducting the experiment
Fill the jar with excess water and close the lid to prevent air bubbles from getting inside. Place the jar with the lid facing up against the mirror. Now you can look in the “mirror”.
Bring your face closer and look inside. There will be a thumbnail image. Now start tilting the jar to the side without lifting it from the mirror.
What will happen?
The reflection of your head in the jar, of course, will also tilt until it turns upside down, and your legs will still not be visible. Lift the can and the reflection will turn over again.
Cocktail with bubbles
What needs to be prepared?
- A glass with a strong solution of table salt.
- A battery from a flashlight.
- Two pieces of copper wire approximately 10 cm long.
- Fine sandpaper.
Conducting the experiment
Clean the ends of the wire with fine sandpaper. Connect one end of the wire to each pole of the battery. Dip the free ends of the wires into a glass with the solution.
What happened?
Bubbles will rise near the lowered ends of the wire.
Lemon battery
What needs to be prepared?
- Lemon, thoroughly washed and wiped dry.
- Two pieces of insulated copper wire approximately 0.2–0.5 mm thick and 10 cm long.
- Steel paper clip.
- A light bulb from a flashlight.
Conducting the experiment
Strip the opposite ends of both wires at a distance of 2–3 cm. Insert a paper clip into the lemon and screw the end of one of the wires to it. Insert the end of the second wire into the lemon, 1–1.5 cm from the paperclip. To do this, first pierce the lemon in this place with a needle. Take the two free ends of the wires and apply them to the contacts of the light bulb.
What will happen?
The light will light up!
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 a 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 conduct 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, launched it into his eye and pressed it on the back side of the eyeball. The resulting 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. Because of this method, the plane cannot be refueled on the ground, because the fuel will leak out through those very cracks. Therefore, at first only a small amount of fuel is filled into the plane, and refueling takes place in the air.
Where can water freeze at +20 °C?
Water can freeze in a pipeline at a temperature of +20 °C if methane is present in this water (to be more precise, gas hydrate is formed from water and methane). Methane molecules “push apart” water molecules, as they occupy more volume. This leads to a decrease in internal water pressure and an increase in freezing temperature.
Whose Nobel medals were hidden from the Nazis in dissolved form?
In Nazi Germany, the Nobel Prize was banned after the Peace Prize was awarded to the opponent of National Socialism, Karl von Ossietzky, in 1935. German physicists Max von Laue and James Frank entrusted the custody of their gold medals to Niels Bohr. When the Germans occupied Copenhagen in 1940, the chemist de Hevesy dissolved these medals in aqua regia. After the end of the war, de Hevesy extracted the gold hidden in the aqua regia and donated it to the Royal Swedish Academy of Sciences. New medals were made there and re-presented to von Laue and Frank.
Which famous physicist was awarded the Nobel Prize in Chemistry?
Ernest Rutherford's research was primarily in the field of physics and once stated that "all sciences can be divided into two groups - physics and stamp collecting." However, he was awarded the Nobel Prize in chemistry, which came as a surprise to both him and other scientists. Subsequently, he noticed that of all the transformations that he was able to observe, “the most unexpected was his own transformation from a physicist to a chemist.”
Why do insects hit lamps?
Insects orient themselves in flight according to the light. They fix the source - the Sun or the Moon - and maintain a constant angle between it and their course, taking a position in which the rays always illuminate the same side. However, if the rays from celestial bodies are almost parallel, then from an artificial light source the rays diverge radially. And when an insect chooses a lamp for its course, it moves in a spiral, gradually approaching it.
How to distinguish a boiled egg from a raw one?
If a boiled egg is spun on a smooth surface, it will quickly spin in a given direction and will spin for quite a long time, while a raw egg will stop much earlier. This happens because a hard-boiled egg rotates as a single whole, while a raw egg has liquid contents, loosely bound to the shell. Therefore, when rotation begins, the liquid contents, due to the inertia of rest, lag behind the rotation of the shell and slow down the movement. Also, during rotation, you can briefly stop the rotation with your finger. For the same reasons, a boiled egg will stop immediately, but a raw egg will continue to spin after you remove your finger.
Why does a rainbow have an arc shape?
Sun rays passing through raindrops in the air are decomposed into a spectrum, since different colors of the spectrum are refracted in the drops at different angles. As a result, a circle is formed - a rainbow, part of which we see from the ground in the form of an arc, and the center of the circle lies on the straight line “The Sun is the eye of the observer.” If the light in the drop is reflected twice, you can see a secondary rainbow.
How is ice able to flow?
Ice is subject to fluidity - the ability to deform under stress determines the movement of ice in huge glaciers. Some Himalayan glaciers move at a speed of 2-3 meters per day.
Why can Asians and Africans carry weights on their heads?
Residents of Africa and Asia easily carry heavy loads on their heads. This is explained by the laws of physics. When walking, the human body rises and falls, thus expending forces on lifting the load. At the same time, the head rises and falls with a smaller vertical amplitude than the whole body, and this feature was developed through evolution: the brain was protected from concussion, while the springy spine with a double bend served as a spring.
Why can you increase the rate of freezing of water by preheating it?
In 1963, Tanzanian schoolboy Erasto Mpemba discovered that hot water freezes faster in the freezer than cold water. In honor of him, this phenomenon was called the Mpemba effect. Until now, scientists have not been able to accurately explain the cause of the phenomenon, and the experiment is not always successful: it requires certain conditions.
Why doesn't ice sink in water?
Water is the only freely occurring substance on Earth whose density in the liquid state is greater than in the solid state. Therefore, ice does not sink in water. It is thanks to this that bodies of water usually do not freeze to the bottom, although this is possible at extreme air temperatures.
What influences the direction in which the water swirls?
The Coriolis force, caused by the rotation of the Earth around its own axis, does not in any way affect the torsion of the water funnel in the bathtub. Its effect can be seen in the twisting of air masses (clockwise in the southern hemisphere and counterclockwise in the northern), but this force is too small to spin a small and fast funnel. The direction in which the water rotates depends on other factors, such as the direction of the threads in the drain hole or the configuration of the pipes.
Who is considered the world's first programmer?
The world's first programmer was an Englishwoman, Ada Lovelace. In the mid-19th century, she drew up a plan of operations for the prototype of a modern computer - Charles Babbage's Analytical Engine, with the help of which it was possible to solve Bernoulli's equation, which expresses the law of conservation of energy of a moving fluid.
What particles can take a million years to rise from the Sun's core to its surface?
Light travels slower in a transparent medium than in a vacuum. For example, photons undergoing many collisions on their way from the solar core, which emits energy, can take about a million years to reach the surface of the Sun. However, moving in outer space, the same photons reach the Earth in just 8.3 minutes.
When was the Earth's gravitational field weakened?
On April 1, 1976, English astronomer Patrick Moore played a prank on BBC radio by announcing that at 9:47 a.m. a rare astronomical effect would occur: Pluto would pass behind Jupiter, enter into gravitational interaction with it, and slightly weaken the Earth’s gravitational field. If listeners jump at this moment, they should experience a strange feeling. Since 9.47am the BBC has received hundreds of calls reporting strange feelings, with one woman even saying she and her friends left their chairs and flew around the room.
Why are there 7 colors in the rainbow?
Although the multicolor spectrum of the rainbow is continuous, according to tradition, 7 colors are distinguished in it. It is believed that Isaac Newton was the first to choose this number. Moreover, initially he distinguished only five colors - red, yellow, green, blue and violet, which he wrote about in his “Optics”. But later, trying to create a correspondence between the number of colors in the spectrum and the number of fundamental tones of the musical scale, Newton added two more colors.
Why did Dirac want to refuse the Nobel Prize?
When the English physicist Paul Dirac was awarded the Nobel Prize in 1933, he wanted to refuse it because he hated advertising. However, Rutherford nevertheless persuaded his colleague to receive the award, since refusal would have become even more advertising.
What did the inventor of radar say when he was speeding?
Scottish physicist Robert Watson-Watt was once stopped by a policeman for speeding, after which he said: “If I had known what you would do with it, I would never have invented radar!”
What makes snowflakes unique?
Due to the enormous variety of snowflake shapes, it is believed that no two snowflakes have the same crystal structure. According to some physicists, there are more variants of such forms than there are atoms in the observable Universe.
How did maritime smugglers hide alcohol from American customs officers during Prohibition?
During Prohibition in the United States, most smuggled alcohol came by sea. Smugglers prepared in advance for sudden customs inspections at sea. They tied a bag of salt or sugar to each box, and when danger approached, they threw it into the water. After a certain time, the contents of the bags dissolved with water, and the loads floated to the surface.
What did the Celsius scale originally look like?
In the original Celsius scale, the freezing point of water was taken as 100 degrees, and the boiling point of water as 0. This scale was inverted by Carl Linnaeus, and in this form it is used to this day.
Which discovery of Einstein was awarded the Nobel Prize?
The archives of the Nobel Committee preserved about 60 nominations for Einstein in connection with the formulation of the theory of relativity, but the prize was awarded only for his explanation of the photoelectric effect.
As a rule, few students like school science about the properties and structure of matter. And indeed - tedious problem solving, complex formulas, incomprehensible combinations of special characters, etc. In general, sheer gloom and melancholy. If you think so, then this material is definitely for you.
In this article we will tell you the most interesting facts about physics, which will make even an indifferent person look at natural science differently. Without a doubt, physics is a very useful and interesting science, and there are a lot of interesting facts about the Universe related to it.
1. Why is the sun red in the morning and evening? A wonderful example of a fact from physical phenomena in nature. Actually, the light of a hot celestial body is white. White glow, with its spectral change, tends to acquire all the colors of the rainbow.
In the mornings and evenings, the sun's rays pass through numerous layers of the atmosphere. Air molecules and tiny dry dust particles can block the passage of sunlight, best allowing only red rays to pass through.
2. Why does time tend to stop at the speed of light? If you believe the general theory of relativity proposed by, the absolute value of the speed of propagation of electromagnetic waves in a vacuum medium is constant and equal to three hundred million meters per second. This is actually a unique phenomenon, given that nothing in our universe can exceed the speed of light, but this is still a theoretical opinion.
In one of the theories, authored by Einstein, there is an interesting section that says that the more you gain speed, the slower time begins to move in comparison with surrounding objects. For example, if you drive a car for an hour, you will age slightly less than if you just lay on your bed at home watching television. Nanoseconds are unlikely to have a noticeable impact on your life, but the proven fact remains a fact.
3. Why doesn’t a bird sitting on an electric wire die from electric shock? A bird sitting on a power line is not shocked because its body is not conductive enough. In places where the bird comes into contact with the wire, a so-called parallel connection is created, and since high-voltage wire is the best conductor of current; only a minimum current flows through the body of the bird itself, which is not able to cause significant harm to the health of the bird.
But as soon as a feathered and downy vertebrate animal standing on a wire comes into contact with a grounded object, for example, a metal part of a high-voltage power line, it instantly burns out, because the resistance in this case becomes too great, and the entire electric current pierces the body of the unfortunate bird.
4. How much dark matter is there in the Universe? We live in a material world, and all that we can see around us is matter. We have the opportunity to touch it, sell it, buy it, we can dispose of the material at our discretion. However, in the Universe there is not only objective reality in the form of matter, but also dark matter (physicists often call it “dark horse”) - this is a type of matter that does not tend to emit electromagnetic waves and interact with them.
For obvious reasons, no one has been able to see or touch dark matter. Scientists have come to the conclusion that it is present in the Universe, having repeatedly observed indirect evidence of its existence. It is generally accepted that its share in the composition of the Universe occupies 22%, while matter familiar to us occupies only 5%.
5. Are there Earth-like planets in the Universe? Undoubtedly they exist! Taking into account the scale of the Universe, the probability of this is estimated by scientists to be quite high.
However, only recently scientists from NASA began to actively discover such planets located no further than 50 light years from the Sun, called exoplanets. Exoplanets are Earth-like planets that orbit the axis of other stars. To date, more than 3,500 Earth-like planets have been found, and scientists are increasingly discovering alternative places for people to live.
6. All objects fall at the same speed. It may seem to some that heavy objects fall down much faster than light objects - this is a completely logical assumption. Surely a hockey puck falls at a much higher speed than a bird feather. In fact, this is so, but not due to the fault of universal gravity - the main reason why we can observe this is that the gas shell surrounding the planet provides powerful resistance.
400 years have passed since I first realized that universal gravity applies to all objects equally, regardless of their gravity. If you could repeat the experiment with a hockey puck and a bird feather in space (where there is no atmospheric pressure), they would fall down at the same speed.
7. How do the northern lights appear on Earth? Throughout their existence, people have observed one of the natural wonders of our planet - the northern lights, but at the same time they could not understand what it is and where it comes from. Ancient people, for example, had their own idea: a group of indigenous Eskimo peoples believed that this was a sacred light that was emitted by the souls of deceased people, and in ancient European countries they assumed that these were military actions that the defenders of their state who died in wars were forever doomed to wage .
The first scientists came a little closer to solving the mysterious phenomenon - they put forward for worldwide discussion the theory that the glow occurs as a result of the reflection of light rays from ice blocks. Modern researchers believe that the multi-colored light is caused by the collision of millions of atoms and dust particles from our atmospheric shell. The fact that the phenomenon is widespread mainly at the poles is explained by the fact that in these areas the power of the Earth's magnetic field is especially strong.
8. Quicksand sucking deep. The force of pulling a stuck foot out of the sand, supersaturated with air and moisture from rising sources, at a speed of 0.1 m/s is equal to the force of lifting an average passenger car. A remarkable fact: quicksand is a non-Newtonian fluid that is not able to completely absorb the human body.
Therefore, people mired in quicksand die from exhaustion or dehydration, excessive ultraviolet radiation or other reasons. God forbid, you find yourself in such a situation; it is worth remembering that it is strictly forbidden to make sudden movements. Try to tilt your body back as high as possible, spread your arms wide and wait for the rescue team to help.
9. Why is the unit of measurement for the strength of alcoholic drinks and temperature called the same - degree? In the 17th-18th centuries, the generally accepted scientific principle of caloric was in effect - the so-called weightless matter, which was located in physical bodies and was the cause of thermal phenomena.
According to this principle, more heated physical bodies contain many times more concentrated caloric than less heated ones, therefore the strength of alcoholic beverages was determined as the temperature of the mixture of substance and caloric.
10. Why doesn't a drop of rain kill a mosquito? Physicists have managed to figure out how mosquitoes manage to fly in rainy weather and why raindrops do not kill bloodsuckers. The insects are the same size as a raindrop, but one droplet weighs 50 times more than a mosquito. The impact of a drop can be compared to a car or even a bus crashing into a person’s body.
Despite this, the rain does not disturb the insects. The question arises - why? The flight speed of a raindrop is about 9 meters per second. When an insect gets inside the shell of a drop, enormous pressure is applied to it. For example, if a person were subjected to such pressure, his body would not be able to withstand it, but a mosquito is able to safely withstand such stress due to the specific structure of the skeleton. And in order to continue flying in a given direction, the mosquito simply needs to shake off its hairs from a drop of rain.
Scientists say that the volume of the drop is quite enough to kill a mosquito if it is on the ground. And the absence of consequences after a drop of rain hits a mosquito is attributed to the fact that the movement associated with the drop allows one to minimize the transfer of energy to the insect.
There is still an unlimited number of facts in this science. And if today’s famous scientists were not interested in physics, we would not know all the interesting things that are happening around us. The achievements of famous physicists allowed us to understand the importance of substantiating laws-prohibitions, laws-statements and absolute laws for the life of mankind.
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 setting. 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 irregularities of the frosted glass, the light is scattered, but the adhesive side of the tape smooths out these irregularities, 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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