WHY can't humans walk straight ahead without reference points?
Unlike some birds, humans do not have an organ to orient themselves according to the geomagnetic field. Nor do we have an analog of the gyroscope that maintains direction on ships and airplanes.
Our vestibular apparatus senses body turns, but to maintain direction they must be summed up, making sure that right and left turns together give zero.
With the many small turns that accompany walking, errors inevitably accumulate. Each subsequent step deviates by a small random amount from the previous one, and without external reference points, the movement deviates more and more from the original direction.
Unlike some birds, humans do not have an organ to orient themselves according to the geomagnetic field. Nor do we have an analog of the gyroscope that maintains direction on ships and airplanes.
Our vestibular apparatus senses body turns, but to maintain direction they must be summed up, making sure that right and left turns together give zero.
With the many small turns that accompany walking, errors inevitably accumulate. Each subsequent step deviates by a small random amount from the previous one, and without external reference points, the movement deviates more and more from the original direction.
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WHY does the water in the glass change its taste overnight?
The first thing that affects taste is temperature. Most of the time, people fill themselves with cool water, and when it gets to room temperature, it doesn't taste as "fresh". However, it is an indirect cause, the main factor in the unpleasant aftertaste of water from the glass is the gases that dissolve in the water overnight. That's why if you pour water in a bottle, it will taste less unpleasant. Interestingly, the higher the temperature, the better the solubility.
Mostly carbon dioxide enters the water, and when it dissolves it forms carbonic acid, which can lower the pH of the water. In addition, acetone gases and aldehydes can dissolve in water.
Scientists say that even in 30 minutes the water can get an unpleasant taste. But if you forget a glass of water for a few days... you'll get all sorts of germs in it.
The first thing that affects taste is temperature. Most of the time, people fill themselves with cool water, and when it gets to room temperature, it doesn't taste as "fresh". However, it is an indirect cause, the main factor in the unpleasant aftertaste of water from the glass is the gases that dissolve in the water overnight. That's why if you pour water in a bottle, it will taste less unpleasant. Interestingly, the higher the temperature, the better the solubility.
Mostly carbon dioxide enters the water, and when it dissolves it forms carbonic acid, which can lower the pH of the water. In addition, acetone gases and aldehydes can dissolve in water.
Scientists say that even in 30 minutes the water can get an unpleasant taste. But if you forget a glass of water for a few days... you'll get all sorts of germs in it.
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WHY do the old phones seem to get slower after a new model is released?
One of the reasons is that applications and the operating system are updated. With each update, applications tend to have more functionality, and consequently the RAM and CPU load increases - the phone has to perform more and more calculations.
When the RAM fails, slower flash memory helps, which also affects performance.
Another reason is the large amount of cache. Few people clean the app cache, but it can take up a serious amount of RAM, especially if you frequently use a browser or social networking apps where you often save music to listen to it offline.
Some apps can clear the cache on their own, but others don't, so do it yourself.
One of the reasons is that applications and the operating system are updated. With each update, applications tend to have more functionality, and consequently the RAM and CPU load increases - the phone has to perform more and more calculations.
When the RAM fails, slower flash memory helps, which also affects performance.
Another reason is the large amount of cache. Few people clean the app cache, but it can take up a serious amount of RAM, especially if you frequently use a browser or social networking apps where you often save music to listen to it offline.
Some apps can clear the cache on their own, but others don't, so do it yourself.
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WHY doesn't the filament in a light bulb burn out?
The thin metal wire in an incandescent bulb gets so hot when an electric current flows through it that it heats up and begins to glow.
Incandescent bulbs can burn for years, but the wire doesn't burn out. The fact is that the bulb has no oxygen inside, and without oxygen, no flame can arise. The bulb is filled with a gas mixture that quenches the flame. Small and weak bulbs, below 25 watts, have a vacuum inside them. When such bulbs break, air rushes into them at such great velocity that a quiet popping sound is heard.
And without the glass housing that insulates the filament from the oxygen, the metal wire would flash only for a moment and immediately burn up like a meteor.
The thin metal wire in an incandescent bulb gets so hot when an electric current flows through it that it heats up and begins to glow.
Incandescent bulbs can burn for years, but the wire doesn't burn out. The fact is that the bulb has no oxygen inside, and without oxygen, no flame can arise. The bulb is filled with a gas mixture that quenches the flame. Small and weak bulbs, below 25 watts, have a vacuum inside them. When such bulbs break, air rushes into them at such great velocity that a quiet popping sound is heard.
And without the glass housing that insulates the filament from the oxygen, the metal wire would flash only for a moment and immediately burn up like a meteor.
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WHY does earwax form?
We occasionally have to clean the yellowish mass out of our ears. Where does it come from? The fact is that our external auditory canal has four thousand wax glands. These glands just produce a substance called earwax.
Since wax is so sticky, dust and dirt clings to it. Thus, it protects the ears from contamination, not allowing dirt to penetrate far inside. It is strictly forbidden to clean your ears with thin objects, such as matches. You could damage your eardrums. Some people produce more earwax than others.
If too much wax is produced, it can block the ear canals and cause hearing loss. In such cases, you should definitely see a doctor.
We occasionally have to clean the yellowish mass out of our ears. Where does it come from? The fact is that our external auditory canal has four thousand wax glands. These glands just produce a substance called earwax.
Since wax is so sticky, dust and dirt clings to it. Thus, it protects the ears from contamination, not allowing dirt to penetrate far inside. It is strictly forbidden to clean your ears with thin objects, such as matches. You could damage your eardrums. Some people produce more earwax than others.
If too much wax is produced, it can block the ear canals and cause hearing loss. In such cases, you should definitely see a doctor.
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WHY do humans live longer than other mammals?
Scientists may have just discovered a major key to the search for immortality by discovering that our lifespan is inextricably linked to the rate by which our cells undergo genetic mutations.
Although it is logical to assume that our probability of death increases as these mutations accumulate over time, such a hypothesis fails to account for an inconsistency known as the Peto paradox. If death depends on the accumulation of somatic mutations, then larger species with more cells should receive more mutations and therefore have shorter lifespans.
For example, the authors found that human cells undergo an average of 47 replacement mutations per year, giving us an average lifespan of 83.7 years.
Scientists may have just discovered a major key to the search for immortality by discovering that our lifespan is inextricably linked to the rate by which our cells undergo genetic mutations.
Although it is logical to assume that our probability of death increases as these mutations accumulate over time, such a hypothesis fails to account for an inconsistency known as the Peto paradox. If death depends on the accumulation of somatic mutations, then larger species with more cells should receive more mutations and therefore have shorter lifespans.
For example, the authors found that human cells undergo an average of 47 replacement mutations per year, giving us an average lifespan of 83.7 years.
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WHY can't bees fly over mirrors?
In 1963, the Austrian entomologist Herbert Heran and the German behavioral scientist Martin Lindauer noticed something strange about the way honeybees fly through the air. When a group of bees was trained to fly over a lake, they could only fly safely to the other shore if there were waves and ripples on the surface of the water.
At the same time, when the lake was mirror-smooth, the insects suddenly lost their orientation - and even fell into the water. The results of that study confirmed the idea that bees use visual cues to navigate during flight.
In other words, when the surface below the bees is mirrored, the insects assume that the ground below them is much farther away than it really is, and they lower their altitude to the limit.
In 1963, the Austrian entomologist Herbert Heran and the German behavioral scientist Martin Lindauer noticed something strange about the way honeybees fly through the air. When a group of bees was trained to fly over a lake, they could only fly safely to the other shore if there were waves and ripples on the surface of the water.
At the same time, when the lake was mirror-smooth, the insects suddenly lost their orientation - and even fell into the water. The results of that study confirmed the idea that bees use visual cues to navigate during flight.
In other words, when the surface below the bees is mirrored, the insects assume that the ground below them is much farther away than it really is, and they lower their altitude to the limit.
WHY does a dozen bear a separate name?
For it has many divisors
A dozen is the smallest number that has six different divisors, four of which are in a row: 1, 2, 3, 4, 6, 12. It is convenient in use, so counting in dozens was used in some monetary systems and in cattle breeding, where derivatives were also used.
Inch dozens are grosses (144) and dozen grosses are masses (1728). We are left with the division of the dial into 12 hours and the word "dozen" from duodecimal counting.
For it has many divisors
A dozen is the smallest number that has six different divisors, four of which are in a row: 1, 2, 3, 4, 6, 12. It is convenient in use, so counting in dozens was used in some monetary systems and in cattle breeding, where derivatives were also used.
Inch dozens are grosses (144) and dozen grosses are masses (1728). We are left with the division of the dial into 12 hours and the word "dozen" from duodecimal counting.
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WHY do people blink?
Studies tell us that the average person blinks once every 2 to 10 seconds. We do this automatically as our eyelids protect our eyes from damage. Sometimes we blink intentionally, using what is called "sign language". As an example, we may blink to get attention, inviting another person to flirt. Sometimes we blink to express surprise, as if to say, "I can't believe my eyes!"
In humans, the inner surface of the upper and lower eyelids, as well as the eyes themselves, are lined with a thin, almost transparent membrane, the conjunctiva. The conjunctiva serves to moisten the surface of the eyes, because they need moisture to move properly. During blinking, the eyelid spreads moisture through the conjunctiva and also directs it to the corners of the eye.
Studies tell us that the average person blinks once every 2 to 10 seconds. We do this automatically as our eyelids protect our eyes from damage. Sometimes we blink intentionally, using what is called "sign language". As an example, we may blink to get attention, inviting another person to flirt. Sometimes we blink to express surprise, as if to say, "I can't believe my eyes!"
In humans, the inner surface of the upper and lower eyelids, as well as the eyes themselves, are lined with a thin, almost transparent membrane, the conjunctiva. The conjunctiva serves to moisten the surface of the eyes, because they need moisture to move properly. During blinking, the eyelid spreads moisture through the conjunctiva and also directs it to the corners of the eye.
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WHY is maple syrup hard to obtain?
The tradition of maple sap harvesting, borrowed by Canadians from the Indians, took shape in their favorite and annually held in March, the national holiday of the inhabitants of Southern Quebec and Ontario. It is possible to get 20-25 liters of the most valuable sap from one tree only from sugar maple (Acer saccharinum).
These trees, which reach 30 m in height, grow in the south-east of Canada. To collect the sap, an incision is made on the trunk, approximately 20-30 cm above the ground, into which tubes are inserted leading to vessels where the sap, called passoka, flows. To obtain a sweet maple syrup or sugar, which instead of sucrose contains more useful dektrose and trace elements, the juice is thickened by evaporation. It takes 40 liters of juice to make 1 liter of syrup.
Maple syrup is an essential ingredient in many Canadian dishes. It is used in ice cream, soufflés, porridges and even some meat dishes.
The tradition of maple sap harvesting, borrowed by Canadians from the Indians, took shape in their favorite and annually held in March, the national holiday of the inhabitants of Southern Quebec and Ontario. It is possible to get 20-25 liters of the most valuable sap from one tree only from sugar maple (Acer saccharinum).
These trees, which reach 30 m in height, grow in the south-east of Canada. To collect the sap, an incision is made on the trunk, approximately 20-30 cm above the ground, into which tubes are inserted leading to vessels where the sap, called passoka, flows. To obtain a sweet maple syrup or sugar, which instead of sucrose contains more useful dektrose and trace elements, the juice is thickened by evaporation. It takes 40 liters of juice to make 1 liter of syrup.
Maple syrup is an essential ingredient in many Canadian dishes. It is used in ice cream, soufflés, porridges and even some meat dishes.
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WHY is it dangerous for cats and dogs to go extinct?
Many cats and dogs, especially ornamental breeds, are almost incapable of making their own food in the wild. Even urban stray dogs and cats live mostly off people - intentional feeding and food scraps.
Furthermore, even completely feral dogs tend to lose competition to wild dogs like wolves, coyotes, etc. Living in the same territory as them, without human support, willing or unwilling, they quickly become extinct. However, in the absence of wild competitors, some dogs and cats are quite capable of mastering an independent life.
The most famous example is the Australian dingo, the feral descendant of domestic dogs, now the largest predator in the Australian fauna. In Australia, as well as in a number of other places, there are stable populations of feral domestic cats.
Many cats and dogs, especially ornamental breeds, are almost incapable of making their own food in the wild. Even urban stray dogs and cats live mostly off people - intentional feeding and food scraps.
Furthermore, even completely feral dogs tend to lose competition to wild dogs like wolves, coyotes, etc. Living in the same territory as them, without human support, willing or unwilling, they quickly become extinct. However, in the absence of wild competitors, some dogs and cats are quite capable of mastering an independent life.
The most famous example is the Australian dingo, the feral descendant of domestic dogs, now the largest predator in the Australian fauna. In Australia, as well as in a number of other places, there are stable populations of feral domestic cats.
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WHY does the water jet narrow toward the bottom?
Slow and calm - laminar, as physicists say - the jet from a circular faucet first has a cross-section equal to the inner diameter of the pipe. Under the action of gravity, the flow accelerates, and since the flow of water doesn't change, the jet should narrow.
One can take a different look at it. Among two drops, that came out of the pipe with a small time gap, the first one starts accelerating earlier, and its detachment from the second one is constantly growing. Thus, gravity stretches the jet vertically. Since the volume of water between the drops remains the same, the jet is thinning.
At that, it is compressed by surface tension forces, and when the jet becomes quite thin - 2-3 mm - they also crush it into separate drops.
Slow and calm - laminar, as physicists say - the jet from a circular faucet first has a cross-section equal to the inner diameter of the pipe. Under the action of gravity, the flow accelerates, and since the flow of water doesn't change, the jet should narrow.
One can take a different look at it. Among two drops, that came out of the pipe with a small time gap, the first one starts accelerating earlier, and its detachment from the second one is constantly growing. Thus, gravity stretches the jet vertically. Since the volume of water between the drops remains the same, the jet is thinning.
At that, it is compressed by surface tension forces, and when the jet becomes quite thin - 2-3 mm - they also crush it into separate drops.
WHY do people like the smell after it rains?
The smell of rain has a term: petrichor.
When rain falls on the ground, water enters microcracks and pores. The air in them forms bubbles on the wet surface, which, when they burst, release many microdroplets into the air.
These tiny particles, containing oils of plant origin, are picked up by air currents and are spread around, creating that unique and beloved by many fragrance.
For the same reason, by the way, when it rains, a huge number of soil bacteria end up in the air. So when you say you smell wet soil, it is actually a molecule produced by a certain type of bacteria. This molecule, geosmin, is created by Streptomyces bacteria.
The smell of rain has a term: petrichor.
When rain falls on the ground, water enters microcracks and pores. The air in them forms bubbles on the wet surface, which, when they burst, release many microdroplets into the air.
These tiny particles, containing oils of plant origin, are picked up by air currents and are spread around, creating that unique and beloved by many fragrance.
For the same reason, by the way, when it rains, a huge number of soil bacteria end up in the air. So when you say you smell wet soil, it is actually a molecule produced by a certain type of bacteria. This molecule, geosmin, is created by Streptomyces bacteria.
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WHY do museums keep some paintings under glass while others don't?
Traditionally, oil paintings are exhibited without glass. The painting is normally coated with a transparent varnish, which makes it resistant to exposure and allows for wet cleaning. Graphics are usually displayed under glass, as pencil, watercolor, ink and pastel are easily damaged and almost impossible to clean.
In some cases, oil paintings are also protected by glass. For example, against fading due to ultraviolet light or when cracks in the paint prevent wet cleaning, as well as in cases of special value and threats of vandalism.
Traditionally, oil paintings are exhibited without glass. The painting is normally coated with a transparent varnish, which makes it resistant to exposure and allows for wet cleaning. Graphics are usually displayed under glass, as pencil, watercolor, ink and pastel are easily damaged and almost impossible to clean.
In some cases, oil paintings are also protected by glass. For example, against fading due to ultraviolet light or when cracks in the paint prevent wet cleaning, as well as in cases of special value and threats of vandalism.
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WHY can't a koala be a family pet?
Recently, the thought of a koala pet has been visiting animal lovers more and more often. After all, looking at this charming fluffy animal, similar to a plush toy, you just uncontrollably want to cuddle and pet it.
However, keeping a koala in captivity is not easy. Mainly because of nutrition. After all, the koala eats only eucalyptus leaves of certain species. And nothing else can replace this "delicacy". Also, koalas prefer to eat at night and drink no water at all, except when they are sick.
Recently, the thought of a koala pet has been visiting animal lovers more and more often. After all, looking at this charming fluffy animal, similar to a plush toy, you just uncontrollably want to cuddle and pet it.
However, keeping a koala in captivity is not easy. Mainly because of nutrition. After all, the koala eats only eucalyptus leaves of certain species. And nothing else can replace this "delicacy". Also, koalas prefer to eat at night and drink no water at all, except when they are sick.
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WHY do domestic hens lay unfertilized eggs?
A mature hen's egg leaves the oviduct to be fertilized. There it develops into an egg, whether or not fertilization occurs.
In the wild, a hen's egg maturation is triggered only under certain conditions, one of which is regular visual contact with the rooster. As a result, the hen usually lays fertilized eggs. After laying a sufficient number of them, the maturation of eggs is blocked, and the bird proceeds to incubation.
Domestic hens have been selected for continuous egg laying, and their reproductive system has undergone changes. Egg maturation is no longer dependent on the presence of the rooster.
A mature hen's egg leaves the oviduct to be fertilized. There it develops into an egg, whether or not fertilization occurs.
In the wild, a hen's egg maturation is triggered only under certain conditions, one of which is regular visual contact with the rooster. As a result, the hen usually lays fertilized eggs. After laying a sufficient number of them, the maturation of eggs is blocked, and the bird proceeds to incubation.
Domestic hens have been selected for continuous egg laying, and their reproductive system has undergone changes. Egg maturation is no longer dependent on the presence of the rooster.
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WHY do animals also need variety?
As observations show, many animals feel frustrated when there is a prolonged lack of new information and access to things to play with. Their behavior resembles that of a bored human.
The ability of animals to be homesick is also evidenced by the fact that even adults spend a lot of time playing and suffer when deprived of this opportunity.
Such behavior is most noticeable in monkeys, raptors, as well as in a number of birds, such as cranes and parrots.
As observations show, many animals feel frustrated when there is a prolonged lack of new information and access to things to play with. Their behavior resembles that of a bored human.
The ability of animals to be homesick is also evidenced by the fact that even adults spend a lot of time playing and suffer when deprived of this opportunity.
Such behavior is most noticeable in monkeys, raptors, as well as in a number of birds, such as cranes and parrots.
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WHY do crows caw?
In order to explain why crows caw, we need to realize that the crow is a remarkably social bird. It is an extraordinarily intelligent creature, on a par with dolphins and monkeys. And thus, it has established a greater contact with its tribesmen.
Specifically, the morning of these birds begins with the convocation of congeners. Specialists assert that several crows can caw in unison for this purpose, so that the summoning would be better heard by others.
Those, who have flown in, generally greet the gathering as well. Then the crows hold a sort of gathering.
The flock, nestled in a tree, decides where to fly, where danger awaits, and other such things. Considering that crows have a rather rich vocabulary, their coddling can be long, noisy, and full of various interesting intonations.
In order to explain why crows caw, we need to realize that the crow is a remarkably social bird. It is an extraordinarily intelligent creature, on a par with dolphins and monkeys. And thus, it has established a greater contact with its tribesmen.
Specifically, the morning of these birds begins with the convocation of congeners. Specialists assert that several crows can caw in unison for this purpose, so that the summoning would be better heard by others.
Those, who have flown in, generally greet the gathering as well. Then the crows hold a sort of gathering.
The flock, nestled in a tree, decides where to fly, where danger awaits, and other such things. Considering that crows have a rather rich vocabulary, their coddling can be long, noisy, and full of various interesting intonations.
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WHY shouldn't we eat hot bread?
Previously, natural sourdough was used to make bread lush. But these days, when artificial yeast is added, people experience adverse effects after eating fresh and hot bread.
The human stomach has difficulty digesting it, and this may lead to the aggravation of gastritis. Besides, freshly baked bread causes fermentation in the intestines, resulting in the formation of excessive gas, colic and intestinal pain.
Previously, natural sourdough was used to make bread lush. But these days, when artificial yeast is added, people experience adverse effects after eating fresh and hot bread.
The human stomach has difficulty digesting it, and this may lead to the aggravation of gastritis. Besides, freshly baked bread causes fermentation in the intestines, resulting in the formation of excessive gas, colic and intestinal pain.
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WHY can gastric juice dissolve razor blades?
The stomach digests food thanks to a caustic hydrochloric acid with a high pH (hydrogen concentration) ranging from 2 to 3.
A famous phenomenon was the French entertainer Michel Lotito, who was listed in the Guinness Book of World Records in 2007 for his outstanding ability to eat inorganic objects. This man could easily devour rubber, glass and metal.
At his performances, Michel Lotito amazed the audience by swallowing bicycles, supermarket carts, TVs, computers, beds, candelabras, skis, glasses, and his most outstanding "achievement" was eating a Cessna-150, for which he spent two years of his life. Although his main advantage is his thick stomach walls, it would be impossible without the acidity of his gastric juice.
The stomach digests food thanks to a caustic hydrochloric acid with a high pH (hydrogen concentration) ranging from 2 to 3.
A famous phenomenon was the French entertainer Michel Lotito, who was listed in the Guinness Book of World Records in 2007 for his outstanding ability to eat inorganic objects. This man could easily devour rubber, glass and metal.
At his performances, Michel Lotito amazed the audience by swallowing bicycles, supermarket carts, TVs, computers, beds, candelabras, skis, glasses, and his most outstanding "achievement" was eating a Cessna-150, for which he spent two years of his life. Although his main advantage is his thick stomach walls, it would be impossible without the acidity of his gastric juice.