WHY are movies shot against a green background?
The green background is used in films in order to replace it with computer-generated visual effects: a single-color green canvas transforms into a panorama of the city, for instance, during the post-production phase.
Technically, the background color can be anything - gray, white, black or purple, but films are shot against a green background, as this color stands out the most (that is, it is easier to highlight and replace it with another color or image later on).
The green background is used in films in order to replace it with computer-generated visual effects: a single-color green canvas transforms into a panorama of the city, for instance, during the post-production phase.
Technically, the background color can be anything - gray, white, black or purple, but films are shot against a green background, as this color stands out the most (that is, it is easier to highlight and replace it with another color or image later on).
WHY do people grab their earlobe when their finger is burned?
The earlobe is the coldest part of the body (available), and it is normal to look for something colder when burned.
Moreover, the lobe has many different receptors, so they are projected to certain internal organs of our body and warming the burned fingers on the earlobe helps to reduce the pain.
The earlobe is the coldest part of the body (available), and it is normal to look for something colder when burned.
Moreover, the lobe has many different receptors, so they are projected to certain internal organs of our body and warming the burned fingers on the earlobe helps to reduce the pain.
WHY do wounds itch when they heal?
The injured tissue releases the neurotransmitter histamine abundantly. Immediately after injury, it triggers an inflammatory response and later prompts tissue stem cells to migrate to the damaged area and repair the tissue.
It turns out that histamine irritates the nerve endings in the skin, causing itching.
The injured tissue releases the neurotransmitter histamine abundantly. Immediately after injury, it triggers an inflammatory response and later prompts tissue stem cells to migrate to the damaged area and repair the tissue.
It turns out that histamine irritates the nerve endings in the skin, causing itching.
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WHY are there wooden planks on F1 cars?
Formula 1 cars have been continuously improved to increase downforce, which has been achieved, among other things, by minimizing ground clearance.
Since 1994, to combat accidents and improve safety, a simple 10mm thick beech wood composite board has been mandatory on the underside of all racing cars. After the race, the boards are always checked, and for wear and tear beyond the allotted limit, the driver's result may be invalidated.
Formula 1 cars have been continuously improved to increase downforce, which has been achieved, among other things, by minimizing ground clearance.
Since 1994, to combat accidents and improve safety, a simple 10mm thick beech wood composite board has been mandatory on the underside of all racing cars. After the race, the boards are always checked, and for wear and tear beyond the allotted limit, the driver's result may be invalidated.
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WHY is dieting incompatible with alcohol?
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It's not even so much that alcohol increases appetite and lowers self-control, but that the brain, having detected the presence of ethyl alcohol in the blood, stops the metabolism, including the process of turning fat into glucose, and concentrates on removing alcohol and its toxic derivatives from the body as quickly as possible.
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Since your body is capable of absorbing no more than 15 to 30 ml of pure alcohol per hour, the process of digesting a can of beer, for example, will stop fat burning for about an hour and a half.
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It's not even so much that alcohol increases appetite and lowers self-control, but that the brain, having detected the presence of ethyl alcohol in the blood, stops the metabolism, including the process of turning fat into glucose, and concentrates on removing alcohol and its toxic derivatives from the body as quickly as possible.
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Since your body is capable of absorbing no more than 15 to 30 ml of pure alcohol per hour, the process of digesting a can of beer, for example, will stop fat burning for about an hour and a half.
WHY are drinks carbonated?
Carbonated beverages are drinks saturated with carbon dioxide, characterized by a peculiar, beloved by many taste, refreshing properties and the so-called sparkling, i.e. intensive and prolonged release of gas bubbles.
In addition to the special taste, the main commercial property of carbon dioxide - preservative (disinfecting, disinfectant, antimicrobial) - is intensively exploited in the production of beverages today.
Carbonated beverages are drinks saturated with carbon dioxide, characterized by a peculiar, beloved by many taste, refreshing properties and the so-called sparkling, i.e. intensive and prolonged release of gas bubbles.
In addition to the special taste, the main commercial property of carbon dioxide - preservative (disinfecting, disinfectant, antimicrobial) - is intensively exploited in the production of beverages today.
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WHY can some fungi turn ants into zombies?
Some parasites are capable of dramatically altering their host's behavior to achieve their goals, turning it into a zombie.
These include the cordyceps lopsided fungus, which penetrates the ant's body and then somehow forces the insect to follow a place optimal for the parasite's development.
The ant seeks out the plant, climbs to a height of 20-30 cm, finds a leaf with a certain temperature and humidity, and bites into the central vein on the underside of the leaf. The ant then dies and the fungus sprouts from its body.
Some parasites are capable of dramatically altering their host's behavior to achieve their goals, turning it into a zombie.
These include the cordyceps lopsided fungus, which penetrates the ant's body and then somehow forces the insect to follow a place optimal for the parasite's development.
The ant seeks out the plant, climbs to a height of 20-30 cm, finds a leaf with a certain temperature and humidity, and bites into the central vein on the underside of the leaf. The ant then dies and the fungus sprouts from its body.
π±7π2
WHY does a person need privacy?
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A person should be alone for at least two hours a day staying in a state of peace. It is just as vital for mental health as communication.
The smooth flow of thoughts, self-knowledge and reflection, sometimes just emptiness and silence - we tend to do this unknowingly, but we need the solitude.
On the way to and from work, disconnecting from the world in public transportation, idly looking at storefronts, not planning to shop, etc. We need solitude to balance our souls.
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A person should be alone for at least two hours a day staying in a state of peace. It is just as vital for mental health as communication.
The smooth flow of thoughts, self-knowledge and reflection, sometimes just emptiness and silence - we tend to do this unknowingly, but we need the solitude.
On the way to and from work, disconnecting from the world in public transportation, idly looking at storefronts, not planning to shop, etc. We need solitude to balance our souls.
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WHY is it quiet outside when it's snowing?
Sound is a mechanical oscillation of a certain frequency that propagates in solid, liquid, and gaseous media. As the layer of freshly fallen snow grows, more and more empty cells containing air appear between the snowflakes.
Sound waves hitting the snow layer are not reflected from it as well as, for example, from a solid homogeneous surface, and some of them are absorbed by the snow cover. But if the snow settles, the number of air cells will immediately decrease, and the sound can be better reflected from the surface.
That's why it's quietest outside when the snow is still soft and freshly fallen. After a few hours, the snow cover thickens, and the amazing silence and charm of the snowfall dissipates.
Sound is a mechanical oscillation of a certain frequency that propagates in solid, liquid, and gaseous media. As the layer of freshly fallen snow grows, more and more empty cells containing air appear between the snowflakes.
Sound waves hitting the snow layer are not reflected from it as well as, for example, from a solid homogeneous surface, and some of them are absorbed by the snow cover. But if the snow settles, the number of air cells will immediately decrease, and the sound can be better reflected from the surface.
That's why it's quietest outside when the snow is still soft and freshly fallen. After a few hours, the snow cover thickens, and the amazing silence and charm of the snowfall dissipates.
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WHY do champions adore to bite their medals?
Athletes first decided to bite their medals in 1991. The British steeplechase team did it. As the athletes admitted, the photographers asked them to do something weird and amusing for the frame, as the traditional posing with the award was no longer so interesting.
According to some historians, metal biting began back in the Middle Ages. Allegedly thatβs how pirates tested gold coins for authenticity. Gold is soft enough, so the dent marks caused by the teeth must have remained on the precious metal. For comparison, gold has a hardness of 2.5, silver 2.7, and platinum 4.3.
Athletes first decided to bite their medals in 1991. The British steeplechase team did it. As the athletes admitted, the photographers asked them to do something weird and amusing for the frame, as the traditional posing with the award was no longer so interesting.
According to some historians, metal biting began back in the Middle Ages. Allegedly thatβs how pirates tested gold coins for authenticity. Gold is soft enough, so the dent marks caused by the teeth must have remained on the precious metal. For comparison, gold has a hardness of 2.5, silver 2.7, and platinum 4.3.
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WHY are the buttons on men's shirts sewn on the right but the ones on women's shirts stitched on the left?
High society women used to dress with the help of maids. It was easier for the helpers to button the buttons, so they were placed on the left side.
Men, on the other hand, preferred to dress themselves, so it was more convenient for them to have the buttons on the right.
Men used to carry weapons on the left side, so the left shelf was on top of the right, so the hand wouldn't cling to the clothes. It was also easier to reach for a weapon that was under his clothes with this option. If a man was already holding a weapon, it was easier for him to unbuckle his clothes with his left hand. In cold weather, men could keep their right hand, which held the weapon, warm under the left hem.
High society women used to dress with the help of maids. It was easier for the helpers to button the buttons, so they were placed on the left side.
Men, on the other hand, preferred to dress themselves, so it was more convenient for them to have the buttons on the right.
Men used to carry weapons on the left side, so the left shelf was on top of the right, so the hand wouldn't cling to the clothes. It was also easier to reach for a weapon that was under his clothes with this option. If a man was already holding a weapon, it was easier for him to unbuckle his clothes with his left hand. In cold weather, men could keep their right hand, which held the weapon, warm under the left hem.
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WHY do mirrors change left to right, but not up to down?
The mirror is not aware of your position; it simply reflects the light that hits it. Then why, when the reflected light hits your eye's photoreceptors, does your image change from left to right?
Actually, the question of what makes the horizontal axis so special in the context of a mirror is itself incorrect. The fact is that the mirror does not reflect from left to right or top to bottom, but it does reflect backwards.
In other words, your mirror reflection is not reversed, but inverted into the third dimension, like a glove being turned inside out.
The mirror is not aware of your position; it simply reflects the light that hits it. Then why, when the reflected light hits your eye's photoreceptors, does your image change from left to right?
Actually, the question of what makes the horizontal axis so special in the context of a mirror is itself incorrect. The fact is that the mirror does not reflect from left to right or top to bottom, but it does reflect backwards.
In other words, your mirror reflection is not reversed, but inverted into the third dimension, like a glove being turned inside out.
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WHY does metal ring?
When deformed slightly, forces arise in the metal, tending to restore its original shape. However, these forces "bend the stick": the metal skips the equilibrium position and deforms in the opposite direction with acceleration. Then the elastic forces change direction, and everything repeats.
Sound vibrations arise, which pass from the metal to the air. The frequencies of the vibrations depend on the elastic properties of the material as well as the mass and shape of the object made of it. Predicting how a particular object will ring is not easy.
When deformed slightly, forces arise in the metal, tending to restore its original shape. However, these forces "bend the stick": the metal skips the equilibrium position and deforms in the opposite direction with acceleration. Then the elastic forces change direction, and everything repeats.
Sound vibrations arise, which pass from the metal to the air. The frequencies of the vibrations depend on the elastic properties of the material as well as the mass and shape of the object made of it. Predicting how a particular object will ring is not easy.
π3
WHY does hot metal glow?
When quanta of light move chaotically in space, physicists speak of a photon gas with a certain temperature. Every object tends to equalize its temperature with the surrounding photon gas: a cold object is heated by this gas, and a hot object gives energy to the gas in the form of radiation.
At room temperature, this radiation is invisible photons of the infrared range. But when heated to 400-500 Β°C, visible red light appears; at higher temperatures, yellow, white, and blue light emerges.
When quanta of light move chaotically in space, physicists speak of a photon gas with a certain temperature. Every object tends to equalize its temperature with the surrounding photon gas: a cold object is heated by this gas, and a hot object gives energy to the gas in the form of radiation.
At room temperature, this radiation is invisible photons of the infrared range. But when heated to 400-500 Β°C, visible red light appears; at higher temperatures, yellow, white, and blue light emerges.
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WHY does a drunk driver fog up his car windows?
Cause the dew point for water vapor rises if there is alcohol vapor in the air
The dew point is the temperature to which air containing a certain amount of water vapor must be cooled before the vapor begins to condense. The temperature of the glass is approximately the same as the outside temperature. If it is lower than the dew point for the cabin air, the windows will fog up.
Cause the dew point for water vapor rises if there is alcohol vapor in the air
The dew point is the temperature to which air containing a certain amount of water vapor must be cooled before the vapor begins to condense. The temperature of the glass is approximately the same as the outside temperature. If it is lower than the dew point for the cabin air, the windows will fog up.
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WHY do children move around a lot?
It helps them develop.
Movement is necessary for children primarily for the development of the nervous and musculoskeletal systems. With age, the capacity for volitional control and action planning becomes apparent, so the impulses that children express in movement are implemented in the mind of adults.
It helps them develop.
Movement is necessary for children primarily for the development of the nervous and musculoskeletal systems. With age, the capacity for volitional control and action planning becomes apparent, so the impulses that children express in movement are implemented in the mind of adults.
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WHY is a circle exactly 360 degrees?
In Sumer, and later in Babylon, the decimal number system was used. In this system, numbers from 1 to 59 were written in the decimal system, then counted in "sixties", then in 3600 (= 60Β²), and so on.
It was then that the circle began to be divided into six times 60 parts, which were later called degrees. But why not just into 60 parts? There are different versions. One explains this choice by the duration of the year (365,25 days), that is, the sun for a day is moved relative to the stars by about 1 Β°.
According to another version, this division is associated with a regular hexagon inscribed into a circle. Such a construction was found on a cuneiform tablet found in 1936. It was used to estimate the ratio of the length of the circle to its diameter.
In Sumer, and later in Babylon, the decimal number system was used. In this system, numbers from 1 to 59 were written in the decimal system, then counted in "sixties", then in 3600 (= 60Β²), and so on.
It was then that the circle began to be divided into six times 60 parts, which were later called degrees. But why not just into 60 parts? There are different versions. One explains this choice by the duration of the year (365,25 days), that is, the sun for a day is moved relative to the stars by about 1 Β°.
According to another version, this division is associated with a regular hexagon inscribed into a circle. Such a construction was found on a cuneiform tablet found in 1936. It was used to estimate the ratio of the length of the circle to its diameter.
WHY do goats wear beards?
Circumstantial evidence of this is the characteristic habit of goats to rub their beards with the secret of their under-tail glands (which are absent in females), which contain sex pheromones.
As zoologists assume, it is a "physiological calendar" that allows congeners to determine the age, condition and also to become an individual.
This feature plays an important role for contacts between members of the same species.
Circumstantial evidence of this is the characteristic habit of goats to rub their beards with the secret of their under-tail glands (which are absent in females), which contain sex pheromones.
As zoologists assume, it is a "physiological calendar" that allows congeners to determine the age, condition and also to become an individual.
This feature plays an important role for contacts between members of the same species.
WHY does gargling with salt water cure a sore throat?
Gargling with salt water is a common treatment for sore throats. According to otolaryngologists, gargling with a solution consisting of half a teaspoon of salt and a quarter cup of warm water relieves the pain caused by inflammation. Similarly, if soda is added to salt water, the solution can break down dense mucus.
The solution cleanses the mouth, temporarily washing away bacteria and pus.
Gargling with salt water is a common treatment for sore throats. According to otolaryngologists, gargling with a solution consisting of half a teaspoon of salt and a quarter cup of warm water relieves the pain caused by inflammation. Similarly, if soda is added to salt water, the solution can break down dense mucus.
The solution cleanses the mouth, temporarily washing away bacteria and pus.
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WHY does friction cause an object to heat up?
Object surfaces are not perfectly flat. Groups of atoms and molecules form a topography with protrusions and depressions. When the protrusions of two parts come close together, they can catch on each other mechanically or get bound by the forces of intermolecular attraction.
As a result, the atoms on the surface of the sliding parts first shift slightly from their equilibrium positions, and then, when the shift becomes too great, the bond between them is broken, and they, like on springs, return to their original position. In doing so, they gain speed and push neighboring atoms, causing them to move chaotically.
And the chaotic motion of the atoms is heat.
Object surfaces are not perfectly flat. Groups of atoms and molecules form a topography with protrusions and depressions. When the protrusions of two parts come close together, they can catch on each other mechanically or get bound by the forces of intermolecular attraction.
As a result, the atoms on the surface of the sliding parts first shift slightly from their equilibrium positions, and then, when the shift becomes too great, the bond between them is broken, and they, like on springs, return to their original position. In doing so, they gain speed and push neighboring atoms, causing them to move chaotically.
And the chaotic motion of the atoms is heat.
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