WHY can sound be heard at a great distance on a rainy day?
There is a state of sound refraction caused by temperature inversion. When the ground and air near the ground is colder than the air above, sound travels faster at altitude than it does over the ground.
A sound wave, angled upward relative to the earth's surface, is gradually deflected backward so that it hits the ground a mile or more from where it began. On a rainy day, rain cools the ground, but the air above the clouds remains warm.
The temperature inversion effect was the bane of outdoor rock concerts. They needed a roof to stop the celestial wave. No amount of walls would help.
There is a state of sound refraction caused by temperature inversion. When the ground and air near the ground is colder than the air above, sound travels faster at altitude than it does over the ground.
A sound wave, angled upward relative to the earth's surface, is gradually deflected backward so that it hits the ground a mile or more from where it began. On a rainy day, rain cools the ground, but the air above the clouds remains warm.
The temperature inversion effect was the bane of outdoor rock concerts. They needed a roof to stop the celestial wave. No amount of walls would help.
WHY does snow glisten in the sun?
Snowflakes are ice crystals with many flat facets which act as microscopic mirrors. Those that reflect sunlight directly into the eye give a bright point. And if you move a little bit, the rays of other snowflakes hit your eye.
Therefore, when you keep moving, the shiny dots alternate with each other. Freshly fallen snow is shinier than lain snow, as flat edges of snowflakes are scratched, broken, and melted with time.
Snowflakes are ice crystals with many flat facets which act as microscopic mirrors. Those that reflect sunlight directly into the eye give a bright point. And if you move a little bit, the rays of other snowflakes hit your eye.
Therefore, when you keep moving, the shiny dots alternate with each other. Freshly fallen snow is shinier than lain snow, as flat edges of snowflakes are scratched, broken, and melted with time.
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WHY can sound be heard at a great distance on a rainy day?
There is a state of sound refraction caused by temperature inversion. When the ground and air near the ground is colder than the air above, sound travels faster at altitude than it does over the ground.
A sound wave, angled upward relative to the earth's surface, is gradually deflected backward so that it hits the ground a mile or more from where it began. On a rainy day, rain cools the ground, but the air above the clouds remains warm.
The temperature inversion effect was the bane of outdoor rock concerts. They needed a roof to stop the celestial wave. No amount of walls would help.
There is a state of sound refraction caused by temperature inversion. When the ground and air near the ground is colder than the air above, sound travels faster at altitude than it does over the ground.
A sound wave, angled upward relative to the earth's surface, is gradually deflected backward so that it hits the ground a mile or more from where it began. On a rainy day, rain cools the ground, but the air above the clouds remains warm.
The temperature inversion effect was the bane of outdoor rock concerts. They needed a roof to stop the celestial wave. No amount of walls would help.
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WHY shouldn't trash be burned in volcanoes?
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The reason is that dumping trash into the lava lakes of volcanoes can trigger an eruption. Lava lakes are volatile, so if you pierce their surfaces with something cold, like garbage, you cause a chain reaction of explosions with compressed and acidic vapor.
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Also, all the moisture accumulated in the debris instantly evaporates, the steam expands, comes out, rips the debris and creates bursts of molten rock.
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The reason is that dumping trash into the lava lakes of volcanoes can trigger an eruption. Lava lakes are volatile, so if you pierce their surfaces with something cold, like garbage, you cause a chain reaction of explosions with compressed and acidic vapor.
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Also, all the moisture accumulated in the debris instantly evaporates, the steam expands, comes out, rips the debris and creates bursts of molten rock.
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WHY does tea leave a stain on the cup?
Tea leaves contain phenolic compounds, tannins, giving the strong drink an astringent taste, and alkaloids, primarily thein. When the tea is brewed, these come out in solution and react with each other. As it cools, the solubility of this compound drops and it is partially released on the surface of the liquid as a film.
When the cup is tilted and sipped from it, this film ends up on the walls and dries out. Plaque is not harmful to health, but its regular occurrence is a reason to wonder if the tea you drink is too strong.
Tea leaves contain phenolic compounds, tannins, giving the strong drink an astringent taste, and alkaloids, primarily thein. When the tea is brewed, these come out in solution and react with each other. As it cools, the solubility of this compound drops and it is partially released on the surface of the liquid as a film.
When the cup is tilted and sipped from it, this film ends up on the walls and dries out. Plaque is not harmful to health, but its regular occurrence is a reason to wonder if the tea you drink is too strong.
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WHY are nuclear powered spaceships not made?
Nuclear fuel contains hundreds of thousands of times more energy than chemical fuel, but it is inefficient to heat the working body with it. The limited thermal stability of the materials makes it impractical to raise the temperature higher than in chemical engines. Thus, the jet velocity cannot be boosted either.
Another thing is to use non-thermal acceleration of the working body, as in ion engines, where ions dispersed by the electric field fly an order of magnitude faster than the thermal exhaust. However, the power of such engines is still small, and they have enough energy from solar panels.
Considering the high cost and hazards of nuclear power sources, they serve so far only for power and heating of vehicles exploring the outer part of the solar system.
Nuclear fuel contains hundreds of thousands of times more energy than chemical fuel, but it is inefficient to heat the working body with it. The limited thermal stability of the materials makes it impractical to raise the temperature higher than in chemical engines. Thus, the jet velocity cannot be boosted either.
Another thing is to use non-thermal acceleration of the working body, as in ion engines, where ions dispersed by the electric field fly an order of magnitude faster than the thermal exhaust. However, the power of such engines is still small, and they have enough energy from solar panels.
Considering the high cost and hazards of nuclear power sources, they serve so far only for power and heating of vehicles exploring the outer part of the solar system.
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WHY is the prison uniform striped?
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The striped uniform allowed a fugitive to be found quickly. It did not blend in with the surroundings and helped search for the prisoner. Also, such a color of clothing immediately singled out a fugitive from the crowd of people. The uniforms of modern colors - red, orange and yellow - also do an excellent job of these functions.
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Another purpose of striped uniforms is uniformity. In prisons absolutely all prisoners wore robes with black and white stripes. Such uniformity and identical clothing had a psychological effect, reducing the inmate's initiative.
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The striped uniform allowed a fugitive to be found quickly. It did not blend in with the surroundings and helped search for the prisoner. Also, such a color of clothing immediately singled out a fugitive from the crowd of people. The uniforms of modern colors - red, orange and yellow - also do an excellent job of these functions.
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Another purpose of striped uniforms is uniformity. In prisons absolutely all prisoners wore robes with black and white stripes. Such uniformity and identical clothing had a psychological effect, reducing the inmate's initiative.
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WHY are sewer manholes round?
The greater ratio of the cross-sectional area of the round manhole hole to the length of the circumference of its body than in a square or rectangular. As a result, you can reduce the cost of production by reducing the consumption of materials without compromising performance.
Round shape allows you to ensure that the cover itself will not fall through the hatch during its assembly or disassembly. In principle, this problem can be solved by using a hatch, repeating the shape of any curve of constant width, but the circle of all possible such figures is the most technologically advanced.
The greater ratio of the cross-sectional area of the round manhole hole to the length of the circumference of its body than in a square or rectangular. As a result, you can reduce the cost of production by reducing the consumption of materials without compromising performance.
Round shape allows you to ensure that the cover itself will not fall through the hatch during its assembly or disassembly. In principle, this problem can be solved by using a hatch, repeating the shape of any curve of constant width, but the circle of all possible such figures is the most technologically advanced.
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WHY do crab sticks have nothing to do with crabs?
The recipe for this snack originated in 1973 in Japan and hasn't changed much since then. The need for crab sticks was born out of the fact that at some point the number of crabs, a terribly essential attribute of Japanese cuisine, began to dwindle rapidly.
Ingenious Japanese came up with a replacement. They took as the basis a dish called "Kamaboko" - for its cooking cod fish fillets are used - it is pure white color. These fish fillets are crushed, then ground, and in this way they obtain surimi meat. Potatoes, soy sauce, starch, egg powder and flavorings are added. Then the resulting mass is made into oblong sticks and evaporated to get rid of the fat.
Completing the process is the application of food coloring red or orange.
The recipe for this snack originated in 1973 in Japan and hasn't changed much since then. The need for crab sticks was born out of the fact that at some point the number of crabs, a terribly essential attribute of Japanese cuisine, began to dwindle rapidly.
Ingenious Japanese came up with a replacement. They took as the basis a dish called "Kamaboko" - for its cooking cod fish fillets are used - it is pure white color. These fish fillets are crushed, then ground, and in this way they obtain surimi meat. Potatoes, soy sauce, starch, egg powder and flavorings are added. Then the resulting mass is made into oblong sticks and evaporated to get rid of the fat.
Completing the process is the application of food coloring red or orange.
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WHY is it so hard to win from a toy machine?
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Anyone who has tried to get a toy out of a grabber knows that it's much harder than it appears. Vox explains that it's not the skill of the players, but the machines themselves, which are set up to cheat.
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The edition has studied the manual to one of these machines and found that the "paw" of the manipulator is programmed to only sometimes squeeze the toys with full force. The owner can set the probability of the paw squeezing the toy hard enough and when it only grabs it a little.
The machine also has a "reset" parameter - the owner can set how frequently the "paw" will drop a toy that has already been grabbed.
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Anyone who has tried to get a toy out of a grabber knows that it's much harder than it appears. Vox explains that it's not the skill of the players, but the machines themselves, which are set up to cheat.
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The edition has studied the manual to one of these machines and found that the "paw" of the manipulator is programmed to only sometimes squeeze the toys with full force. The owner can set the probability of the paw squeezing the toy hard enough and when it only grabs it a little.
The machine also has a "reset" parameter - the owner can set how frequently the "paw" will drop a toy that has already been grabbed.
WHY do Japan lack old houses?
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In this country, it is believed that a house loses value from the first day it is built. In 10 years, the value of a house is halved. After 25 years it is considered far too old to live in and worthless. After that, it is demolished and a new house is built in its place. Even landmarks and major shrines are regularly rebuilt.
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So Japanese people have no examples of old architecture; all the houses are modern. This has a negative effect on the appearance of Japanese cities: the architecture in them is quite monotonous and rarely decorated in any way.
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In this country, it is believed that a house loses value from the first day it is built. In 10 years, the value of a house is halved. After 25 years it is considered far too old to live in and worthless. After that, it is demolished and a new house is built in its place. Even landmarks and major shrines are regularly rebuilt.
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So Japanese people have no examples of old architecture; all the houses are modern. This has a negative effect on the appearance of Japanese cities: the architecture in them is quite monotonous and rarely decorated in any way.
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WHY does the Guinness World Records no longer list the world's fattest animals?
The Guinness World Records contains a myriad of incredible entries: the world's tallest man, the world's shortest rivers, the heaviest tumor... However, several things cannot appear in the book.
Like, no more records related to diet and alcohol consumption are accepted: perhaps because the "Book" doesn't want to get sued for doing something stupid and thereby harming itself.
The Guinness World Records once listed the world's fattest fish, and after that, some fish owners started giving their pets too much food in an attempt to break the record - exactly the kind of behavior the Guinness World Records managers would like to avoid.
The Guinness World Records contains a myriad of incredible entries: the world's tallest man, the world's shortest rivers, the heaviest tumor... However, several things cannot appear in the book.
Like, no more records related to diet and alcohol consumption are accepted: perhaps because the "Book" doesn't want to get sued for doing something stupid and thereby harming itself.
The Guinness World Records once listed the world's fattest fish, and after that, some fish owners started giving their pets too much food in an attempt to break the record - exactly the kind of behavior the Guinness World Records managers would like to avoid.
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WHY do many crabs appear to have one claw larger than the other?
The larger claw, with its powerful teeth, is designed for crushing shells of mollusks and shells of sea urchins, the prey of the crabs. The second claw is fitted with an edge for cutting soft tissues or bristles serving as a filtration apparatus.
In males of half land beckoning crabs, one huge claw has turned into a "tournament weapon": it is used for mating demonstrations and in fights between males.
The larger claw, with its powerful teeth, is designed for crushing shells of mollusks and shells of sea urchins, the prey of the crabs. The second claw is fitted with an edge for cutting soft tissues or bristles serving as a filtration apparatus.
In males of half land beckoning crabs, one huge claw has turned into a "tournament weapon": it is used for mating demonstrations and in fights between males.
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WHY do cooking smells spread throughout the house?
Due to the heated air. All odors sooner or later spread throughout the entire space available to them. However, cooking smells tend to have an amplified effect. The thing is, the stove heats the air above it as it cooks.
By rising, it forms currents carrying odorous substances from cooking and roasting foods around the room.
Due to the heated air. All odors sooner or later spread throughout the entire space available to them. However, cooking smells tend to have an amplified effect. The thing is, the stove heats the air above it as it cooks.
By rising, it forms currents carrying odorous substances from cooking and roasting foods around the room.
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WHY does a fly hit the glass when a section of window is open nearby?
A fly exhibits mosaic vision, and its eyes consist of a large number of facets. A fly may have as many as 8,000 of them. Each facet can be viewed as a tiny eyeball. It consists of a lens and a crystal.
The point is that the fly is unable to discern whether or not there is a glass in front of it. It is due to low visual acuity. Therefore, the insect simply tries to fly forward in the hope of luck. And a side-by-side open window doesn't make it any easier for it to enter the street, as the fly has no idea whether it can fly out there without any problems.
In contrast, if you take the insect in your hand and let it go in front of the open bid, it will fly out immediately, without hesitation.
A fly exhibits mosaic vision, and its eyes consist of a large number of facets. A fly may have as many as 8,000 of them. Each facet can be viewed as a tiny eyeball. It consists of a lens and a crystal.
The point is that the fly is unable to discern whether or not there is a glass in front of it. It is due to low visual acuity. Therefore, the insect simply tries to fly forward in the hope of luck. And a side-by-side open window doesn't make it any easier for it to enter the street, as the fly has no idea whether it can fly out there without any problems.
In contrast, if you take the insect in your hand and let it go in front of the open bid, it will fly out immediately, without hesitation.
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WHY don't trees perish in winter?
Cause of the cell sap patterns. The cell sap of trees accumulates sugars that lower the freezing point of the sap, preventing it from turning into ice. Moreover, the plant's cellulose itself is a good insulator.
Yet severe frosts can lead to the death of the tree. And plants are the most vulnerable after harvesting, since most of the minerals and sugars go to the formation and growth of fruits, and in the trunk cells they are present in minimal quantities.
Cause of the cell sap patterns. The cell sap of trees accumulates sugars that lower the freezing point of the sap, preventing it from turning into ice. Moreover, the plant's cellulose itself is a good insulator.
Yet severe frosts can lead to the death of the tree. And plants are the most vulnerable after harvesting, since most of the minerals and sugars go to the formation and growth of fruits, and in the trunk cells they are present in minimal quantities.
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WHY are there no parachutes on civil aircraft?
First, most accidents occur during takeoff and landing, and at altitude there is no oxygen for breathing. Secondly, a successful parachute jump requires special training, and if you try to jump out of an airliner in a crowd of passengers, the chances of rescue are close to zero.
Instead of supplying passengers with unreliable personal rescue equipment, it is more effective to invest in improving flight safety in general.
First, most accidents occur during takeoff and landing, and at altitude there is no oxygen for breathing. Secondly, a successful parachute jump requires special training, and if you try to jump out of an airliner in a crowd of passengers, the chances of rescue are close to zero.
Instead of supplying passengers with unreliable personal rescue equipment, it is more effective to invest in improving flight safety in general.
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WHY doesn't it tickle when you tickle yourself?
The brain decreases skin sensitivity
Tickling is caused by irritation of the tactile receptors on the skin. Their sensitivity is controlled by the spinal cord and brain. If the irritation is caused by touching another part of your own body (which the receptors in the part being touched tell the brain), the brain dulls the sensitivity of the receptors, preventing the tickle from occurring.
The brain decreases skin sensitivity
Tickling is caused by irritation of the tactile receptors on the skin. Their sensitivity is controlled by the spinal cord and brain. If the irritation is caused by touching another part of your own body (which the receptors in the part being touched tell the brain), the brain dulls the sensitivity of the receptors, preventing the tickle from occurring.
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WHY and how do people hear the inner voice?
Speech is formed in childhood, first as an external voice (the child says everything out loud), and then it is interiorized (becomes internal). The nerve impulses to the vocal cords are essentially the same, but weaker, than those of audible speech. The processes of speech and thinking develop together; we form verbal-logical thinking.
These are our almost nonstop "inner voices." When the inner voice speaks, we are essentially thinking, and some of the nerve impulses run through the familiar pathways of speech. This is how we experience this "phantom" speech of ours.
Speech is formed in childhood, first as an external voice (the child says everything out loud), and then it is interiorized (becomes internal). The nerve impulses to the vocal cords are essentially the same, but weaker, than those of audible speech. The processes of speech and thinking develop together; we form verbal-logical thinking.
These are our almost nonstop "inner voices." When the inner voice speaks, we are essentially thinking, and some of the nerve impulses run through the familiar pathways of speech. This is how we experience this "phantom" speech of ours.
WHY is dust not useless?
Although some people think dust is an inconvenience, it actually keeps people alive. It plays an essential role in the condensation of moisture, resulting in rain and fog, which are necessary for plant growth.
Moreover, thanks to the property of atmospheric dust to scatter light, the eyes of earthly creatures are not exposed to the blindingly bright light of direct sunlight and we can observe beautiful sunsets and sunrises.
Although some people think dust is an inconvenience, it actually keeps people alive. It plays an essential role in the condensation of moisture, resulting in rain and fog, which are necessary for plant growth.
Moreover, thanks to the property of atmospheric dust to scatter light, the eyes of earthly creatures are not exposed to the blindingly bright light of direct sunlight and we can observe beautiful sunsets and sunrises.
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