WHY is the navel concave or convex?
In 90% of people the navel is sunken (hidden inward) and forms a dimple on the abdomen, while 10% of people have a convex navel (clearly visible from the outside).
Congenital anomalies accompanied by a deformity of the umbilical zone are detected immediately after birth. In infants with a cutaneous umbilicus, the skin of the abdominal wall passes over the adjacent part of the umbilical cord.
As a result, after the umbilical cord falls off, a noticeable bulge is formed. As the baby grows, the bulge sometimes retracts, the appearance of the belly button normalizes. However, some patients have a convex navel for the rest of their lives.
In 90% of people the navel is sunken (hidden inward) and forms a dimple on the abdomen, while 10% of people have a convex navel (clearly visible from the outside).
Congenital anomalies accompanied by a deformity of the umbilical zone are detected immediately after birth. In infants with a cutaneous umbilicus, the skin of the abdominal wall passes over the adjacent part of the umbilical cord.
As a result, after the umbilical cord falls off, a noticeable bulge is formed. As the baby grows, the bulge sometimes retracts, the appearance of the belly button normalizes. However, some patients have a convex navel for the rest of their lives.
WHY do humans have 32 teeth?
Geneticists have theorized that our ancestors originally had 44 teeth each. The reason was that they consumed mostly solid foods.
Subsequently, due to the fact that the human diet has become dominated by soft foods, the size of the lower jaw decreased, and there was not enough space for molars.
So they sometimes remain in their infancy, and sometimes they erupt incorrectly and break down quickly. Nowadays, we don't consume that much coarse food, and 20-22 teeth are enough to process it.
Geneticists have theorized that our ancestors originally had 44 teeth each. The reason was that they consumed mostly solid foods.
Subsequently, due to the fact that the human diet has become dominated by soft foods, the size of the lower jaw decreased, and there was not enough space for molars.
So they sometimes remain in their infancy, and sometimes they erupt incorrectly and break down quickly. Nowadays, we don't consume that much coarse food, and 20-22 teeth are enough to process it.
👍4
WHY do coins feature notches on their ribs?
Originally, the value of coins was equal to the amount of metal they contained. And crooks used to cut such money from the edges, misappropriating gold and silver. It was incredibly hard to catch them, since no one carried a scale, and it was unrealistic to determine this by eye.
Strangely enough, the solution to this problem was suggested by the not infamous Sir Isaac Newton, who, it turns out, was also an employee of the British Royal Mint. He suggested making thin notches on the edges of the coins, which made the worn-out edges immediately visible.
This procedure is still carried out today, although it was no longer necessary.
Originally, the value of coins was equal to the amount of metal they contained. And crooks used to cut such money from the edges, misappropriating gold and silver. It was incredibly hard to catch them, since no one carried a scale, and it was unrealistic to determine this by eye.
Strangely enough, the solution to this problem was suggested by the not infamous Sir Isaac Newton, who, it turns out, was also an employee of the British Royal Mint. He suggested making thin notches on the edges of the coins, which made the worn-out edges immediately visible.
This procedure is still carried out today, although it was no longer necessary.
🎉2🤩2
WHY did Heineken produce bottles shaped like bricks?
In 1960, Alfred Heineken, grandson of Heineken's founder, visited the Caribbean island of Curaçao and saw thousands of Heineken bottles lying around. Alfred grieved so much that he decided to produce bricks which would solve two problems: poor citizens could build their homes out of empty square bottles and the planet would become less polluted.
Later they produced 100,000 bottles in the form of bricks, but due to the high cost of their production and customer dissatisfaction (square bottles are uncomfortable to hold in your hand) the plant ceased their production. Nobody knows how many houses were built with these bottles.
In 1960, Alfred Heineken, grandson of Heineken's founder, visited the Caribbean island of Curaçao and saw thousands of Heineken bottles lying around. Alfred grieved so much that he decided to produce bricks which would solve two problems: poor citizens could build their homes out of empty square bottles and the planet would become less polluted.
Later they produced 100,000 bottles in the form of bricks, but due to the high cost of their production and customer dissatisfaction (square bottles are uncomfortable to hold in your hand) the plant ceased their production. Nobody knows how many houses were built with these bottles.
WHY do more people drown in fresh water than in salt one?
If you inhale salt water, the high concentration of salt prevents the water from penetrating the lung tissue. When people drown in salt water, that's generally cause they can't get oxygen or expel carbon dioxide. Breathing in salt water creates a physical barrier between air and the lungs.
Fresh water is more "diluted" with ions than the fluid inside the lung cells. Fresh water does not penetrate skin cells because keratin essentially makes them watertight, but water rushes into unprotected lung cells to try to equalize the concentration gradient on the cell membranes. This may cause serious tissue damage, so even if water is removed from the lungs, chances are you won't get better.
If you inhale salt water, the high concentration of salt prevents the water from penetrating the lung tissue. When people drown in salt water, that's generally cause they can't get oxygen or expel carbon dioxide. Breathing in salt water creates a physical barrier between air and the lungs.
Fresh water is more "diluted" with ions than the fluid inside the lung cells. Fresh water does not penetrate skin cells because keratin essentially makes them watertight, but water rushes into unprotected lung cells to try to equalize the concentration gradient on the cell membranes. This may cause serious tissue damage, so even if water is removed from the lungs, chances are you won't get better.
🤩4
WHY do golf balls need indentations?
These "indentations" on the ball are necessary to increase the range of the ball. So air flowing around an uneven ball reduces the vacuum trace created due to velocity.
And the boundary layer of air in a smooth ball doesn't have time to go behind its back side, so it creates a zone of reduced pressure, which means less velocity.
These "indentations" on the ball are necessary to increase the range of the ball. So air flowing around an uneven ball reduces the vacuum trace created due to velocity.
And the boundary layer of air in a smooth ball doesn't have time to go behind its back side, so it creates a zone of reduced pressure, which means less velocity.
👍1
WHY do girls love diamond wedding bands so much?
For five centuries, the diamond has established itself as the most expensive and desirable stone for jewelry. And since the 19th century, it has been considered the most popular stone for engagement and wedding rings.
This tradition was established by De Beers, which monopolized the diamond market in the late 19th century and just after World War II explained in an advertising campaign of historic proportions that diamonds are forever.
Naturally, marketers drew parallels with love and marriage and suggested that men should spend three wages for an engagement ring. The monopoly lasted until the mid-1990s. Today, the once-great "diamond syndicate" owns only 40% of the market.
For five centuries, the diamond has established itself as the most expensive and desirable stone for jewelry. And since the 19th century, it has been considered the most popular stone for engagement and wedding rings.
This tradition was established by De Beers, which monopolized the diamond market in the late 19th century and just after World War II explained in an advertising campaign of historic proportions that diamonds are forever.
Naturally, marketers drew parallels with love and marriage and suggested that men should spend three wages for an engagement ring. The monopoly lasted until the mid-1990s. Today, the once-great "diamond syndicate" owns only 40% of the market.
WHY do we sleep on a pillow?
One of the reasons we use pillows is the anatomy of the human body. When we stand, our head, neck and spine are on the same vertical line.
This line must also be maintained when lying down. That is, for a comfortable sleeping position, the head and the cervical spine should also be on the same line.
One of the reasons we use pillows is the anatomy of the human body. When we stand, our head, neck and spine are on the same vertical line.
This line must also be maintained when lying down. That is, for a comfortable sleeping position, the head and the cervical spine should also be on the same line.
👍5😱1🎉1
WHY don't people still inject themselves with endorphins (happiness hormones) intravenously?
Actually, they do.
It's called "heroin addiction". The chemical structure of opiates is totally unlike our own endorphins (otherwise they wouldn't be able to get from the blood vessels to the brain), but they act exactly the same way on the receptors.
And there is nothing good about this idea, since the brain is instantly hooked on the artificial sensation of concentrated happiness and demands repetition. And after a number of repetitions it reduces the production of its own endorphins.
Actually, they do.
It's called "heroin addiction". The chemical structure of opiates is totally unlike our own endorphins (otherwise they wouldn't be able to get from the blood vessels to the brain), but they act exactly the same way on the receptors.
And there is nothing good about this idea, since the brain is instantly hooked on the artificial sensation of concentrated happiness and demands repetition. And after a number of repetitions it reduces the production of its own endorphins.
👍1
WHY doesn't a person start boiling in a sauna?
In a sauna, the temperature reaches 130 degrees. A person is not boiling in a sauna as he sweats profusely. Evaporating in the dry atmosphere of the sauna, the sweat cools the body, allowing it to maintain a normal temperature.
However, this mechanism cannot work for a long time, so a person is only able to stay in the sauna steam room for a short time.
In a sauna, the temperature reaches 130 degrees. A person is not boiling in a sauna as he sweats profusely. Evaporating in the dry atmosphere of the sauna, the sweat cools the body, allowing it to maintain a normal temperature.
However, this mechanism cannot work for a long time, so a person is only able to stay in the sauna steam room for a short time.
WHY does the homing pigeon always find its way home?
Judging from numerous experiments, pigeons use various principles of orientation, testing one by another. Close to home, they rely mostly on landmarks - say, they may fly along familiar freeways, repeating their curves.
When returning home from an unfamiliar place, pigeons, according to most researchers, orient themselves by the celestial lights (the sun and the stars), as well as by the magnetic field of the earth, which they sense directly thanks to the small magnetic particles in the upper part of their beaks.
Judging from numerous experiments, pigeons use various principles of orientation, testing one by another. Close to home, they rely mostly on landmarks - say, they may fly along familiar freeways, repeating their curves.
When returning home from an unfamiliar place, pigeons, according to most researchers, orient themselves by the celestial lights (the sun and the stars), as well as by the magnetic field of the earth, which they sense directly thanks to the small magnetic particles in the upper part of their beaks.
❤6😱2
WHY does alcohol harm sleep?
Alcohol retards brain activity and exerts a sedative effect that may cause feelings of relaxation and sleepiness. Yet alcohol consumption is actually associated with poor quality and shortened sleep duration.
Although drinking alcohol can lead to falling asleep more quickly, it can affect different stages of sleep, reducing its overall quality.
If you want to get a good night's sleep, sound advice is to avoid drinking alcohol.
Alcohol retards brain activity and exerts a sedative effect that may cause feelings of relaxation and sleepiness. Yet alcohol consumption is actually associated with poor quality and shortened sleep duration.
Although drinking alcohol can lead to falling asleep more quickly, it can affect different stages of sleep, reducing its overall quality.
If you want to get a good night's sleep, sound advice is to avoid drinking alcohol.
WHY is there no cure for color blindness?
Unfortunately, no cure for color blindness exists. There are special glasses and corrective lenses on the market that, according to advertisements, help with color recognition, but they come with undesirable side effects.
Lenses improve color recognition in one part of the spectrum, but in the other part, they worsen it. Many patients also experience unnaturally bright colors during the day and can barely distinguish their surroundings at night. In addition, lenses can ruin depth perception.
For this reason, most people with color blindness learn to adjust. They have no problem with everyday activities.
Many companies these days also consider the needs of people with color blindness: video games and apps often have special modes of operation for colorblind people.
Unfortunately, no cure for color blindness exists. There are special glasses and corrective lenses on the market that, according to advertisements, help with color recognition, but they come with undesirable side effects.
Lenses improve color recognition in one part of the spectrum, but in the other part, they worsen it. Many patients also experience unnaturally bright colors during the day and can barely distinguish their surroundings at night. In addition, lenses can ruin depth perception.
For this reason, most people with color blindness learn to adjust. They have no problem with everyday activities.
Many companies these days also consider the needs of people with color blindness: video games and apps often have special modes of operation for colorblind people.
WHY do clouds not fall to the ground?
Clouds simply aren't rigid objects. They are merely regions of the atmosphere where the air temperature is below the dew point at which moisture condenses.
Conditions near the Earth are typically warmer and condensation doesn't occur. With altitude, the temperature drops, and the dew point is where the lower boundary of the cloud is located. But occasionally, especially in the morning, this altitude is at ground level.
Then the cloud lays on the ground, which we perceive as fog.
Clouds simply aren't rigid objects. They are merely regions of the atmosphere where the air temperature is below the dew point at which moisture condenses.
Conditions near the Earth are typically warmer and condensation doesn't occur. With altitude, the temperature drops, and the dew point is where the lower boundary of the cloud is located. But occasionally, especially in the morning, this altitude is at ground level.
Then the cloud lays on the ground, which we perceive as fog.
👍3😱1
WHY does a thermonuclear bomb explode immediately, but stars take a long time to burn?
Stars hold back the explosion by gravity
For the nuclei of the light elements to enter into a thermonuclear reaction, they need to overcome mutual repulsion (since all the nuclei carry a charge of the same sign).
That is possible at temperatures of tens of millions of degrees, when the atoms are moving fast enough. Hot matter creates high pressure, and thermonuclear energy heats the matter even more.
The bomb at this temperature evaporates instantly, and the pressure causes the products of the explosion to scatter. In stars, the pressure of the plasma is counteracted by gravity, the thermonuclear energy seeps out gradually and is radiated into space.
Stars hold back the explosion by gravity
For the nuclei of the light elements to enter into a thermonuclear reaction, they need to overcome mutual repulsion (since all the nuclei carry a charge of the same sign).
That is possible at temperatures of tens of millions of degrees, when the atoms are moving fast enough. Hot matter creates high pressure, and thermonuclear energy heats the matter even more.
The bomb at this temperature evaporates instantly, and the pressure causes the products of the explosion to scatter. In stars, the pressure of the plasma is counteracted by gravity, the thermonuclear energy seeps out gradually and is radiated into space.
👍2😱1🤩1
WHY does sweets make you thirsty?
It draws water out of the cells.
Sucrose, glucose and fructose do not require digestion and are quickly absorbed. When they enter the blood and tissue fluid, these substances increase the osmotic pressure in the blood and tissue, causing water to be drawn out of the cells.
The hypothalamus immediately triggers a feeling of thirst when it signals the ingestion of sugar. The water drunk dilutes the sugar and is absorbed with it, preventing a sudden rise in osmotic pressure.
It draws water out of the cells.
Sucrose, glucose and fructose do not require digestion and are quickly absorbed. When they enter the blood and tissue fluid, these substances increase the osmotic pressure in the blood and tissue, causing water to be drawn out of the cells.
The hypothalamus immediately triggers a feeling of thirst when it signals the ingestion of sugar. The water drunk dilutes the sugar and is absorbed with it, preventing a sudden rise in osmotic pressure.
WHY do people say "to take English leave"?
In the 18th century, this was the name given to those who left the ball without saying goodbye to their hosts. Although the English themselves attribute the roots of this bad habit to the French, and they "turn the tables" on the Germans. Suffice it to say that the English say "to take French leave" and the French "filer à l'anglaise" (to take English leave).
According to another version, the idiom appeared during the Seven Years' War of 1756-1763, where the English fought the French. As usual, the enemies liked to reproach each other for cowardice, so the deserters were called "to take French leave" or "to take English leave".
In the 18th century, this was the name given to those who left the ball without saying goodbye to their hosts. Although the English themselves attribute the roots of this bad habit to the French, and they "turn the tables" on the Germans. Suffice it to say that the English say "to take French leave" and the French "filer à l'anglaise" (to take English leave).
According to another version, the idiom appeared during the Seven Years' War of 1756-1763, where the English fought the French. As usual, the enemies liked to reproach each other for cowardice, so the deserters were called "to take French leave" or "to take English leave".
👍1
WHY do people perceive air and water at the same temperature in different ways?
It's all about the heat capacity difference. Due to the fact that water is 800 times denser than air, its heat capacity, even in terms of the same mass, is also higher, takes heat from the body much more efficiently.
One can imagine that each square centimeter of body surface should heat 1 degree, 1 cubic centimeter of air which is in contact with it - or 1 cubic centimeter of water. In the latter case, heat will have to be given off several thousand times more.
It's all about the heat capacity difference. Due to the fact that water is 800 times denser than air, its heat capacity, even in terms of the same mass, is also higher, takes heat from the body much more efficiently.
One can imagine that each square centimeter of body surface should heat 1 degree, 1 cubic centimeter of air which is in contact with it - or 1 cubic centimeter of water. In the latter case, heat will have to be given off several thousand times more.
WHY the cloth on the billiard table is green?
The traditional green light for making billiard cloth was chosen as a result of the fact that at first the game was played on the lawns - the whole history of billiards was emphasized by it.
Yet another version exists - it is believed that the green color was chosen because of its wide use in other gambling games. However, today is proven: the green color has a beneficial effect on the eyesight, the eyes rest while playing on a table with a green cloth.
The traditional green light for making billiard cloth was chosen as a result of the fact that at first the game was played on the lawns - the whole history of billiards was emphasized by it.
Yet another version exists - it is believed that the green color was chosen because of its wide use in other gambling games. However, today is proven: the green color has a beneficial effect on the eyesight, the eyes rest while playing on a table with a green cloth.
👍1