WHY do we hear a rustling noise inside a tennis ball?
A tennis ball is not inflated from the outside, like a soccer ball, but from the inside, so to speak. Before fusing its two rubber halves, a tablet consisting of sodium nitrite and ammonia is placed between them.
Sodium nitrite is well known to anyone who loves smoked sausages: it gives the naturally gray stuffing a delicious pink color and specific taste, and is labeled on the packaging as a "color enhancer" E250. Ammonia is a salt that decomposes in water to produce ammonia, which is why the aqueous solution of this gas is called ammonia alcohol.
So, when heated, these two substances react to form nitrogen, water vapor, and table salt. Nitrogen and water vapor expand the ball from the inside. We can hear the rustle inside the ball when the salt crystals are relatively large.
Note that not all modern balls are made in this way, so not every ball rustles.
A tennis ball is not inflated from the outside, like a soccer ball, but from the inside, so to speak. Before fusing its two rubber halves, a tablet consisting of sodium nitrite and ammonia is placed between them.
Sodium nitrite is well known to anyone who loves smoked sausages: it gives the naturally gray stuffing a delicious pink color and specific taste, and is labeled on the packaging as a "color enhancer" E250. Ammonia is a salt that decomposes in water to produce ammonia, which is why the aqueous solution of this gas is called ammonia alcohol.
So, when heated, these two substances react to form nitrogen, water vapor, and table salt. Nitrogen and water vapor expand the ball from the inside. We can hear the rustle inside the ball when the salt crystals are relatively large.
Note that not all modern balls are made in this way, so not every ball rustles.
WHY did one Englishman appear naked in a duel between two gentlemen?
In 1806, two gentlemen, Humphrey Howarth and the Earl of Barrymore, argued in an English bar. A duel was arranged for the next morning, where Howarth appeared completely naked, shocking the assembled audience.
He had previously served as an army surgeon and knew that death often came not from the bullet itself, but from an infection carried with a piece of clothing. The count had no desire to be remembered in history as the man who had killed a naked man in a duel, and the rivals resolved the situation peacefully.
In 1806, two gentlemen, Humphrey Howarth and the Earl of Barrymore, argued in an English bar. A duel was arranged for the next morning, where Howarth appeared completely naked, shocking the assembled audience.
He had previously served as an army surgeon and knew that death often came not from the bullet itself, but from an infection carried with a piece of clothing. The count had no desire to be remembered in history as the man who had killed a naked man in a duel, and the rivals resolved the situation peacefully.
WHY don't people have blue or green hair?
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People have no green, blue or pink hair (unless of course you dye it that way), because we do not have a pigment in our bodies to color our hair in unusual shades.
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Sometimes, the pigment melanin is not produced at all! In this case, his skin is almost white and his hair looks bleached. They are called albinos.
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For this same reason, a person turns gray: gradually the body reduces the production of melanin, which gives the hair its color.
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People have no green, blue or pink hair (unless of course you dye it that way), because we do not have a pigment in our bodies to color our hair in unusual shades.
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Sometimes, the pigment melanin is not produced at all! In this case, his skin is almost white and his hair looks bleached. They are called albinos.
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For this same reason, a person turns gray: gradually the body reduces the production of melanin, which gives the hair its color.
WHY do dogs eat grass?
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Crumpled but not chewed stalks irritate the gastric mucosa and increase the secretion of gastric juice, as well as activating stomach movements. This speeds up the digestion and progression of food.
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If a clump of grass has passed into the intestine, the stems act on its walls, also stimulating the release of secretions and peristaltic movements.
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Crumpled but not chewed stalks irritate the gastric mucosa and increase the secretion of gastric juice, as well as activating stomach movements. This speeds up the digestion and progression of food.
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If a clump of grass has passed into the intestine, the stems act on its walls, also stimulating the release of secretions and peristaltic movements.
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WHY can't kangaroos jump backwards?
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Kangaroos are one of the best jumpers in the animal world, with a jump length of 10-12 meters and travel speed of 50 km/h. In order not to lose balance when jumping, the kangaroo uses its thick, muscular tail at the base for balance.
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This tail, as well as its large feet, is the reason why the kangaroo cannot jump backwards.
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By the way, thanks to this fact, the kangaroo together with the emu, which also can't stagger, appeared on the Australian emblem, illustrating the motto "Australia always goes only forward!"
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Kangaroos are one of the best jumpers in the animal world, with a jump length of 10-12 meters and travel speed of 50 km/h. In order not to lose balance when jumping, the kangaroo uses its thick, muscular tail at the base for balance.
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This tail, as well as its large feet, is the reason why the kangaroo cannot jump backwards.
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By the way, thanks to this fact, the kangaroo together with the emu, which also can't stagger, appeared on the Australian emblem, illustrating the motto "Australia always goes only forward!"
WHY are there two straws added to cocktails?
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Well, there are several reasons. First, it's so that when you order a multi-layered cocktail, you can try different levels without mixing them up. That's why one straw is slightly longer (it goes down to the bottom of the alcohol), while the other straw is slightly shorter (it goes down to the level of juice or grenadine - depending on what kind of drink you're drinking.
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A couple of straws are also added to make it easier to stir the drink.
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Finally, the third version is that two people can drink the cocktail through the straws, which looks very romantic.
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Well, there are several reasons. First, it's so that when you order a multi-layered cocktail, you can try different levels without mixing them up. That's why one straw is slightly longer (it goes down to the bottom of the alcohol), while the other straw is slightly shorter (it goes down to the level of juice or grenadine - depending on what kind of drink you're drinking.
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A couple of straws are also added to make it easier to stir the drink.
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Finally, the third version is that two people can drink the cocktail through the straws, which looks very romantic.
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WHY do dogs chase cats?
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In nature, relations between mammals of prey are always tense: the strong tries to destroy the weak. A tiger never misses an opportunity to kill a wolf or a litter of wolf cubs. Wolves kill lynxes, foxes, raccoon dogs and coyotes at every opportunity; hyenas and hyena dogs attack cubs of lions, leopards and cheetahs.
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Apparently, dogs' attitude toward cats is a legacy of this feud, especially since cats were domesticated much later than dogs.
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In nature, relations between mammals of prey are always tense: the strong tries to destroy the weak. A tiger never misses an opportunity to kill a wolf or a litter of wolf cubs. Wolves kill lynxes, foxes, raccoon dogs and coyotes at every opportunity; hyenas and hyena dogs attack cubs of lions, leopards and cheetahs.
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Apparently, dogs' attitude toward cats is a legacy of this feud, especially since cats were domesticated much later than dogs.
WHY do the winning drivers pour champagne on themselves?
The tradition of pouring champagne over the winners at motor racing awards ceremonies began in 1967. Race driver Dan Gurney won the 24 Hours of Le Mans and at the end of the race the organizers gave him a bottle of champagne. Gurney was so excited by this victory that he immediately uncorked the bottle and began splashing its contents on everyone standing near him.
Since then, the custom has become so ingrained that even during races in countries of the Islamic world (where alcohol is prohibited), special fizzy non-alcoholic drinks are made of champagne for showers.
The tradition of pouring champagne over the winners at motor racing awards ceremonies began in 1967. Race driver Dan Gurney won the 24 Hours of Le Mans and at the end of the race the organizers gave him a bottle of champagne. Gurney was so excited by this victory that he immediately uncorked the bottle and began splashing its contents on everyone standing near him.
Since then, the custom has become so ingrained that even during races in countries of the Islamic world (where alcohol is prohibited), special fizzy non-alcoholic drinks are made of champagne for showers.
WHY can't mammoths be revived using their DNA?
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As we need a living cell, you can't bring anyone back to life with their DNA.
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DNA has the right spatial structure and the right chemical modifications in addition to sequence. Moreover, no one knows how to synthesize DNA of such length.
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To clone a mammoth from the permafrost, there must be living cells in a piece of it, and that doesn't happen.
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The oldest DNA that has been sequenced is 700,000 years old. But it is not a whole molecule, there were many pieces, the sequence was determined, and then they were assembled into a whole genome.
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As we need a living cell, you can't bring anyone back to life with their DNA.
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DNA has the right spatial structure and the right chemical modifications in addition to sequence. Moreover, no one knows how to synthesize DNA of such length.
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To clone a mammoth from the permafrost, there must be living cells in a piece of it, and that doesn't happen.
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The oldest DNA that has been sequenced is 700,000 years old. But it is not a whole molecule, there were many pieces, the sequence was determined, and then they were assembled into a whole genome.
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WHY are there 31 days in some months & 30 days in others?
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Such an order was adopted according to the Julian calendar, 45th century B.C. The scholar Sosigenes, by order of Julius Caesar, created a new calendar, a new system of chronology, where the year was counted 365 days and divided into 12 months. Six hours remained each year and were added every four years to the last month of the year, February.
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February was the last month of the year, so it just had the remaining number of days. Augustus did not want "his" month to be shorter than July (named after Julius) and cut one day off February.
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Actually the number of days in a month is based on the cycle of the Moon 29,5 days; January, March, May, July, August, October, December - 31 days; April, June, September, November - 30 days; February 28 and leap day 29.
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Such an order was adopted according to the Julian calendar, 45th century B.C. The scholar Sosigenes, by order of Julius Caesar, created a new calendar, a new system of chronology, where the year was counted 365 days and divided into 12 months. Six hours remained each year and were added every four years to the last month of the year, February.
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February was the last month of the year, so it just had the remaining number of days. Augustus did not want "his" month to be shorter than July (named after Julius) and cut one day off February.
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Actually the number of days in a month is based on the cycle of the Moon 29,5 days; January, March, May, July, August, October, December - 31 days; April, June, September, November - 30 days; February 28 and leap day 29.
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WHY do cartoon characters have 4 fingers on their hands?
Well, actually, for purely economic reasons. The thing is that drawing a five-fingered brush is a bit more difficult than its simplified version. And when it comes to warm, lamplight, frame-by-frame animation, an extra finger bursts a completely incommensurate amount of animator work.
It was for this reason that Walt Disney, who was not only an animator but also a prominent entrepreneur, cut off his characters' fingers, thereby saving a lot of money.
Disney's savings and the time of his animators went luckily not to the offshore, but to the quality of the studio's work. And the idea was so good that most cartoons still have four fingers to this day.
Well, actually, for purely economic reasons. The thing is that drawing a five-fingered brush is a bit more difficult than its simplified version. And when it comes to warm, lamplight, frame-by-frame animation, an extra finger bursts a completely incommensurate amount of animator work.
It was for this reason that Walt Disney, who was not only an animator but also a prominent entrepreneur, cut off his characters' fingers, thereby saving a lot of money.
Disney's savings and the time of his animators went luckily not to the offshore, but to the quality of the studio's work. And the idea was so good that most cartoons still have four fingers to this day.
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WHY is green a soothing color?
The positive effect of the color green on the human body is well known. Psychologists assert that if you want to find an environment conducive to calm, but also productive work, make sure that you are surrounded by as many green objects as possible.
Psychologists explain the beneficial effect of this color on the human body by the fact that we associate the shades of green with nature, with something alive and fresh.
The green background freshens up the working environment, makes it not so gloomy and sad. Conversely, the gray color will have a negative impact on the general well-being of the employee, and, consequently, on his work.
The positive effect of the color green on the human body is well known. Psychologists assert that if you want to find an environment conducive to calm, but also productive work, make sure that you are surrounded by as many green objects as possible.
Psychologists explain the beneficial effect of this color on the human body by the fact that we associate the shades of green with nature, with something alive and fresh.
The green background freshens up the working environment, makes it not so gloomy and sad. Conversely, the gray color will have a negative impact on the general well-being of the employee, and, consequently, on his work.
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WHY is it hard to drown in salt water just by lying on your back?
The immersion depth of an object depends on its specific gravity relative to the liquid. The specific gravity of the human body and water are almost identical.
But on an inhalation, the body weight becomes slightly less, and one can lie motionless on the surface of a lake, much less a salty sea. On exhalation, the specific gravity increases slightly due to a decrease in body volume, and a person sinks a little.
So as not to drown in calm water, lying on the back, it is enough to keep the air in the lungs, after exhaling immediately making a breath. This, however, requires some skill.
The immersion depth of an object depends on its specific gravity relative to the liquid. The specific gravity of the human body and water are almost identical.
But on an inhalation, the body weight becomes slightly less, and one can lie motionless on the surface of a lake, much less a salty sea. On exhalation, the specific gravity increases slightly due to a decrease in body volume, and a person sinks a little.
So as not to drown in calm water, lying on the back, it is enough to keep the air in the lungs, after exhaling immediately making a breath. This, however, requires some skill.
WHY wouldn't a passenger be able to land the plane if something happened to the pilots?
Let's assume a passenger has access to the cockpit.
Let's assume there is two-way communication with the ground and that they know how to use it, and that there is a pilot of that plane from the ground.
But still the chance is slim to none.
As one instructor who teaches retrained pilots said, even they get lost in the cockpit looking for the right buttons and levers, what about the passenger under stress!
Given the speed of the plane and the rapidity of the action and the fact that leaving for the second circle would be an even greater ordeal, so the passenger would not be able to land the plane.
Let's assume a passenger has access to the cockpit.
Let's assume there is two-way communication with the ground and that they know how to use it, and that there is a pilot of that plane from the ground.
But still the chance is slim to none.
As one instructor who teaches retrained pilots said, even they get lost in the cockpit looking for the right buttons and levers, what about the passenger under stress!
Given the speed of the plane and the rapidity of the action and the fact that leaving for the second circle would be an even greater ordeal, so the passenger would not be able to land the plane.
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WHY can't a tick bite through a tights?
A tick can bite through pantyhose if it puts its proboscis between their threads. But it won't. The fact is that ixodes ticks have no vision, and when they move around the victim's body, they choose a place to bite mainly by touch.
They don't perceive a tissue-covered area as suitable for feeding and look for bare skin. But the mite can get under pantyhose, if they have a hole in them.
A tick can bite through pantyhose if it puts its proboscis between their threads. But it won't. The fact is that ixodes ticks have no vision, and when they move around the victim's body, they choose a place to bite mainly by touch.
They don't perceive a tissue-covered area as suitable for feeding and look for bare skin. But the mite can get under pantyhose, if they have a hole in them.
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WHY is the fruit green at first and then changes color?
Photosynthesis continues in the newly formed fruit, meaning the chlorophyll pigment, which has a green color, is present. As the fruit matures, the chlorophyll breaks down and the synthesis of pigments of other colors intensifies in the fruit. This attracts animals, which contribute to the spread of the seeds.
The contrasting color against the green foliage serves to encourage animals to find the ripe fruits without touching the unripe ones.
Photosynthesis continues in the newly formed fruit, meaning the chlorophyll pigment, which has a green color, is present. As the fruit matures, the chlorophyll breaks down and the synthesis of pigments of other colors intensifies in the fruit. This attracts animals, which contribute to the spread of the seeds.
The contrasting color against the green foliage serves to encourage animals to find the ripe fruits without touching the unripe ones.
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WHY are clouds white at night?
Clouds are made up of water droplets and ice crystals, which are colorless and only partially scatter light hitting them.
At night, low clouds will look whiter than the sky when there is a lot of city light. In contrast, in a dark area, clouds obscure the faint glow of the night sky and look black.
Clouds are made up of water droplets and ice crystals, which are colorless and only partially scatter light hitting them.
At night, low clouds will look whiter than the sky when there is a lot of city light. In contrast, in a dark area, clouds obscure the faint glow of the night sky and look black.
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WHY is there not a single bridge across the Amazon?
No urgent enough necessity.
The fact is that the Amazon, for most of its 6,920 kilometers, passes through sparsely populated areas, meaning that there are very few major roads to which any bridge could be connected. And in the cities and towns bordering the river, boats and ferries are a common means of moving goods and people from shore to shore. So there is no real need to build bridges, except to make travel a little faster and safer.
Beyond that, however, the Amazon is far from an ideal place for any construction. It is very swampy and has soft soil. Construction required very deep foundations, which require a significant financial investment. The river is also greatly affected by seasonal fluctuations, and that adds an extra level of difficulty.
No urgent enough necessity.
The fact is that the Amazon, for most of its 6,920 kilometers, passes through sparsely populated areas, meaning that there are very few major roads to which any bridge could be connected. And in the cities and towns bordering the river, boats and ferries are a common means of moving goods and people from shore to shore. So there is no real need to build bridges, except to make travel a little faster and safer.
Beyond that, however, the Amazon is far from an ideal place for any construction. It is very swampy and has soft soil. Construction required very deep foundations, which require a significant financial investment. The river is also greatly affected by seasonal fluctuations, and that adds an extra level of difficulty.
WHY is a watermelon called a berry?
The scientific definition of a berry.
According to the botanical classification of fruit, a berry is a multiseeded fruit with a relatively thin leathery shell, juicy flesh and seeds in a hard rind.
Watermelon and other fruits of the pumpkin family - melon, pumpkin, cucumber - meet all these conditions, so in terms of botany it is a berry.
The scientific definition of a berry.
According to the botanical classification of fruit, a berry is a multiseeded fruit with a relatively thin leathery shell, juicy flesh and seeds in a hard rind.
Watermelon and other fruits of the pumpkin family - melon, pumpkin, cucumber - meet all these conditions, so in terms of botany it is a berry.
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