WHY do passengers crave tomato juice on planes?
According to experts, about a quarter of passengers choose this drink. It turns out that there is a perfectly logical explanation.
The thing is that at an altitude of 10,000 meters above the ground, a person's taste buds start to work a little differently. Due to pressure and dry air, salt and sugar lose their taste by about 20-30%.
Correspondingly, in order to experience the familiar taste, passengers choose drinks that seem too salty on the ground. Or sour, like tea with lemon. Besides, tomato juice helps to maintain water-salt balance during the flight.
According to experts, about a quarter of passengers choose this drink. It turns out that there is a perfectly logical explanation.
The thing is that at an altitude of 10,000 meters above the ground, a person's taste buds start to work a little differently. Due to pressure and dry air, salt and sugar lose their taste by about 20-30%.
Correspondingly, in order to experience the familiar taste, passengers choose drinks that seem too salty on the ground. Or sour, like tea with lemon. Besides, tomato juice helps to maintain water-salt balance during the flight.
WHY does water flow in different directions in the Northern and Southern Hemispheres?
The effect is attributed to the rotation of the Earth and the Coriolis force.
The Coriolis force is an inertial force that acts on a material point as it moves relative to a rotating reference frame. It causes objects moving along the Earth's surface to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. In the case of flowing down an inclined concave surface, this will give counterclockwise and clockwise motion, respectively.
Still, here is a crucial factor - the degree of influence of this force. And it depends, on the one hand, on the shape of the funnel and adjacent surfaces, on the other hand, on the parameters of the flow and latitude. In other words, the smaller the scale of the flow and the closer to the equator we are, the more microscopic is the influence of the Coriolis force on the background of other forces.
The effect is attributed to the rotation of the Earth and the Coriolis force.
The Coriolis force is an inertial force that acts on a material point as it moves relative to a rotating reference frame. It causes objects moving along the Earth's surface to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. In the case of flowing down an inclined concave surface, this will give counterclockwise and clockwise motion, respectively.
Still, here is a crucial factor - the degree of influence of this force. And it depends, on the one hand, on the shape of the funnel and adjacent surfaces, on the other hand, on the parameters of the flow and latitude. In other words, the smaller the scale of the flow and the closer to the equator we are, the more microscopic is the influence of the Coriolis force on the background of other forces.
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WHY do cheeks turn red in awkward situations?
Feeling ashamed or embarrassed is an extreme situation for the body. Adrenaline, a hormone released, kicks in, taking an active part in the "fight or flight" decision.
By worrying, we get into a defensive position, as if protect ourselves. Especially adrenaline prepares the body to cope with danger: it intensifies the heartbeat, speeds up breathing, increases pupils to get as much visual stimulus as possible.
Adrenaline lowers the digestive process, so energy moves to the muscles, blood vessels increase there, the flow of blood and oxygen speeds up, getting to all corners of the body faster.
Feeling ashamed or embarrassed is an extreme situation for the body. Adrenaline, a hormone released, kicks in, taking an active part in the "fight or flight" decision.
By worrying, we get into a defensive position, as if protect ourselves. Especially adrenaline prepares the body to cope with danger: it intensifies the heartbeat, speeds up breathing, increases pupils to get as much visual stimulus as possible.
Adrenaline lowers the digestive process, so energy moves to the muscles, blood vessels increase there, the flow of blood and oxygen speeds up, getting to all corners of the body faster.
WHY do swifts never touch the ground?
Swifts can neither walk nor swim: their feet are not suited to any kind of movement. At best, if suddenly found on the ground, a swift can crawl a few meters. It cannot even fly from the ground since the wings are far too long while the legs are quite short. The only exception is black swifts, they can jump up to take off.
Swifts feed on "air plankton" - small flying insects. They drink, wash, and mate in flight. And to leave offspring, they nest under roofs or in walls. Swifts live about 20 years, spending all these years in the sky.
Swifts can neither walk nor swim: their feet are not suited to any kind of movement. At best, if suddenly found on the ground, a swift can crawl a few meters. It cannot even fly from the ground since the wings are far too long while the legs are quite short. The only exception is black swifts, they can jump up to take off.
Swifts feed on "air plankton" - small flying insects. They drink, wash, and mate in flight. And to leave offspring, they nest under roofs or in walls. Swifts live about 20 years, spending all these years in the sky.
WHY do rockets count down when launching?
A countdown is an elaborate set of procedures culminating in the ignition of a missile's engine. Depending on the type of vehicle used, the countdown can start from 72 to 96 hours before launch time.
The film Frau im Mond, based on Jules Verne's novel From the Earth to the Moon, was directed by Fritz Lang in 1929. Heroes there had to launch to a satellite of the Earth not in a core, but in a rocket. To maximize the tension, the director and invented the countdown. The film had a great deal of popularity in Germany, and the German rocketeers, who were just testing their first rockets at the range, began to use this countdown.
At first it was just a ritual, but as the complexes got more complicated, so did the technological function: many people were working at the launch site, and everyone was performing their operation at a certain count.
A countdown is an elaborate set of procedures culminating in the ignition of a missile's engine. Depending on the type of vehicle used, the countdown can start from 72 to 96 hours before launch time.
The film Frau im Mond, based on Jules Verne's novel From the Earth to the Moon, was directed by Fritz Lang in 1929. Heroes there had to launch to a satellite of the Earth not in a core, but in a rocket. To maximize the tension, the director and invented the countdown. The film had a great deal of popularity in Germany, and the German rocketeers, who were just testing their first rockets at the range, began to use this countdown.
At first it was just a ritual, but as the complexes got more complicated, so did the technological function: many people were working at the launch site, and everyone was performing their operation at a certain count.
WHY cannot kangaroos jump in reverse?
Kangaroos are among the best jumpers in the animal world, with a jump length of 10-12 meters and travel speed of 50 km/h. To keep its balance when jumping, the kangaroo uses its thick, muscular tail at the base for balance.
This tail, as well as its large feet, is the reason why the kangaroo cannot jump backwards.
Owing to this fact, the kangaroo, in company with the emu, which also cannot stagger, appeared on the coat of arms of Australia, illustrating the motto "Australia always goes only forward!"
Kangaroos are among the best jumpers in the animal world, with a jump length of 10-12 meters and travel speed of 50 km/h. To keep its balance when jumping, the kangaroo uses its thick, muscular tail at the base for balance.
This tail, as well as its large feet, is the reason why the kangaroo cannot jump backwards.
Owing to this fact, the kangaroo, in company with the emu, which also cannot stagger, appeared on the coat of arms of Australia, illustrating the motto "Australia always goes only forward!"
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WHY does the cat sharpen its claws?
When a cat is sharpening wood or furniture, as an example, it's not really sharpening its claws, but rather trying to get rid of the old, blunted upper claw shell.
This shell eventually flakes off as the claw grows, and by getting rid of it, the cat gets a new sharp tool for defense and attack.
Hence, cats so frequently tear up the cloth on upholstered furniture - the peeling off of the claw's top layer gets stuck in it even better than in the wood.
When a cat is sharpening wood or furniture, as an example, it's not really sharpening its claws, but rather trying to get rid of the old, blunted upper claw shell.
This shell eventually flakes off as the claw grows, and by getting rid of it, the cat gets a new sharp tool for defense and attack.
Hence, cats so frequently tear up the cloth on upholstered furniture - the peeling off of the claw's top layer gets stuck in it even better than in the wood.
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WHY can lack of night sleep result in obesity?
Lack of sleep increases appetite, raising the risk of obesity. Due to insufficient sleep, the body mistakenly believes it is short on energy.
Depending on the individual, a healthy night's sleep is 5-10 hours.
Elementary school students should sleep 8-12 hours, and middle school students should sleep 6.5-10 hours. Most adults get 7-8 hours of sleep.
Lack of sleep increases appetite, raising the risk of obesity. Due to insufficient sleep, the body mistakenly believes it is short on energy.
Depending on the individual, a healthy night's sleep is 5-10 hours.
Elementary school students should sleep 8-12 hours, and middle school students should sleep 6.5-10 hours. Most adults get 7-8 hours of sleep.
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WHY is the closest a stall in a public toilet to the door, the fewer germs it contains?
After bacteriological analysis of fifty-one public toilets, experts found that the stall closest to the front door always had the lowest bacteria levels and the most toilet paper. Perhaps the reason is that these stalls due to their proximity to the door seem to people less private, and they instinctively try to get away from possible witnesses.
In any case, you should be careful when visiting a public toilet - as a rule, no one monitors the sterility of latrines, and it's easy to get infected with hepatitis or E. coli.
For urinals, apropos, the opposite is true - the furthest urinals are the cleanest. As a rule, men are more likely to be in a hurry and tend to use the nearest urinal.
After bacteriological analysis of fifty-one public toilets, experts found that the stall closest to the front door always had the lowest bacteria levels and the most toilet paper. Perhaps the reason is that these stalls due to their proximity to the door seem to people less private, and they instinctively try to get away from possible witnesses.
In any case, you should be careful when visiting a public toilet - as a rule, no one monitors the sterility of latrines, and it's easy to get infected with hepatitis or E. coli.
For urinals, apropos, the opposite is true - the furthest urinals are the cleanest. As a rule, men are more likely to be in a hurry and tend to use the nearest urinal.
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WHY is a warming of only 2ยฐ C so severe for the planet?
The world is about 1.2ยฐC warmer now than it was in pre-industrial times. The 144 countries participating in the 2016 Paris Agreement concurred that the world should limit global warming this century to 1.5ยฐC. That's a highly "stringent" goal, with a lower limit of 2ยฐC.
To realize the criticality of 1.5ยฐC, let's take the last ice age as an example. Everyone agrees that the times of such large-scale frosts were extremely harsh. We are only separated from those global temperatures by... 5ยฐะก! At that time, sea level was about 106 meters lower than today by storing a lot of water in the form of ice at the poles. Also, about 32% of the Earth was covered in ice then, compared to about 10% today.
As an example, the oceans provide humans with about 20% of their dietary protein. Ocean acidification caused by climate change could lead to the death of many species, including oysters and crabs. The same will greatly affect the food chain.
The world is about 1.2ยฐC warmer now than it was in pre-industrial times. The 144 countries participating in the 2016 Paris Agreement concurred that the world should limit global warming this century to 1.5ยฐC. That's a highly "stringent" goal, with a lower limit of 2ยฐC.
To realize the criticality of 1.5ยฐC, let's take the last ice age as an example. Everyone agrees that the times of such large-scale frosts were extremely harsh. We are only separated from those global temperatures by... 5ยฐะก! At that time, sea level was about 106 meters lower than today by storing a lot of water in the form of ice at the poles. Also, about 32% of the Earth was covered in ice then, compared to about 10% today.
As an example, the oceans provide humans with about 20% of their dietary protein. Ocean acidification caused by climate change could lead to the death of many species, including oysters and crabs. The same will greatly affect the food chain.
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WHY are vitamins A, C, E named with letters and B1, B6, B12 with numbers?
Cause the B group erroneously included different vitamins.
At the beginning of the 20th century, vitamins were called by their physiological action. The B vitamins had quite similar effects, and they were generally found in the same foods, so at first their names were all "vitamin B".
Later it turned out that it was a whole group of substances with varying chemical natures and they weren't interchangeable. As they were isolated, they began to be given the indices B1, B2, B3, B5, B6, B9, and B12.
Nowadays, though, only the designations B6 and B12 are usually found in the medical literature, the other B vitamins are commonly referred to by their chemical names: B1 for thiamine, B2 for riboflavin, etc.
Cause the B group erroneously included different vitamins.
At the beginning of the 20th century, vitamins were called by their physiological action. The B vitamins had quite similar effects, and they were generally found in the same foods, so at first their names were all "vitamin B".
Later it turned out that it was a whole group of substances with varying chemical natures and they weren't interchangeable. As they were isolated, they began to be given the indices B1, B2, B3, B5, B6, B9, and B12.
Nowadays, though, only the designations B6 and B12 are usually found in the medical literature, the other B vitamins are commonly referred to by their chemical names: B1 for thiamine, B2 for riboflavin, etc.
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WHY are flies attracted to bad smells?
Those smells serving as a warning of the rotting process are attractive to flies for exactly the same reasons. When organic tissue begins to rot, it becomes soft and moist. These are ideal conditions for fly larvae to develop.
Rotting tissue is tempting for females to lay eggs. The larvae can hatch in as little as 12 hours. As soon as they emerge, they burrow into the soft medium, which they feed on for several days. Then they turn into pupae and, after a while, into adults.
Those smells serving as a warning of the rotting process are attractive to flies for exactly the same reasons. When organic tissue begins to rot, it becomes soft and moist. These are ideal conditions for fly larvae to develop.
Rotting tissue is tempting for females to lay eggs. The larvae can hatch in as little as 12 hours. As soon as they emerge, they burrow into the soft medium, which they feed on for several days. Then they turn into pupae and, after a while, into adults.
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WHY is it cold in the mountains if the cold air tends downward?
The atmosphere warms mostly from the Earth's surface and gives off heat into space. Greenhouse gases keep the heat from escaping. The higher up, there are fewer greenhouse gases and the heat can escape more easily. That's why the temperature drops with height.
So, why doesn't the cold air rush downward? Actually, it does, but only with those air masses that are colder than the surrounding air at the same altitude and "sink" in it.
The cold upper layers cannot simply displace the underlying warm air, because it is not only warmer, but also higher in pressure and density.
The atmosphere warms mostly from the Earth's surface and gives off heat into space. Greenhouse gases keep the heat from escaping. The higher up, there are fewer greenhouse gases and the heat can escape more easily. That's why the temperature drops with height.
So, why doesn't the cold air rush downward? Actually, it does, but only with those air masses that are colder than the surrounding air at the same altitude and "sink" in it.
The cold upper layers cannot simply displace the underlying warm air, because it is not only warmer, but also higher in pressure and density.
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WHY do dolphins enjoy chewing fugu fish?
Dolphins seem more human-like at times than we can imagine. The makers of the documentary noticed a strange thing: teenage dolphins were carefully chewing on fugu fish and passing it to each other.
Fugu is known for containing a lethal dose of a neurotoxin in its body, but in small doses this substance has a narcotic effect, and the dolphins seem to be well aware of this.
Dolphins seem more human-like at times than we can imagine. The makers of the documentary noticed a strange thing: teenage dolphins were carefully chewing on fugu fish and passing it to each other.
Fugu is known for containing a lethal dose of a neurotoxin in its body, but in small doses this substance has a narcotic effect, and the dolphins seem to be well aware of this.
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WHY did Nike name its first running shoes "Cortez"?
Nike meant to dub its first running shoes "Aztec," but principle competitor Adidas already had sneakers called "Aztec Gold," and they threatened to sue.
Then one of Nike's co-founders, Bill Bowerman, took the decision to call the new sneakers "Cortez." It was the last name of the Spanish conquistador who invaded Mexico and destroyed the Aztec state.
Nike meant to dub its first running shoes "Aztec," but principle competitor Adidas already had sneakers called "Aztec Gold," and they threatened to sue.
Then one of Nike's co-founders, Bill Bowerman, took the decision to call the new sneakers "Cortez." It was the last name of the Spanish conquistador who invaded Mexico and destroyed the Aztec state.
WHY is Victoria's Secret fragrance more effective than repellents?
Researchers at New Mexico State University tested mosquito repellents popular in the United States. From previous experiments, the authors learned that mosquitoes are attracted to floral and fruity scents, so they used Victoria's Secret Bombshell fragrance in their experiments.
What was the surprise of scientists when they found that Victoria's Secret fragrance was more effective than repellents. That is, the floral scent didn't attract mosquitoes, but, on the contrary, repelled them.
Researchers at New Mexico State University tested mosquito repellents popular in the United States. From previous experiments, the authors learned that mosquitoes are attracted to floral and fruity scents, so they used Victoria's Secret Bombshell fragrance in their experiments.
What was the surprise of scientists when they found that Victoria's Secret fragrance was more effective than repellents. That is, the floral scent didn't attract mosquitoes, but, on the contrary, repelled them.
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WHY is the world's worst pain a cluster headache?
Cluster headache, aka "suicidal headache," is so severe that many scientists believe it's the worst pain a person can experience.
Cluster headaches affect men at a greater rate than women. It occurs in series every few weeks or months. Each attack lasts from 15 minutes to 3 hours. Mostly the pain is concentrated around the eyes or behind the eye.
The exact etiology of the disease is uncertain. Pathological activity of the hypothalamus is considered to play a leading role in the development of the disease, as indirectly confirmed by the rhythmic nature of the headache episodes. Triggering factors responsible for triggering new attacks are individual for each patient.
Cluster headache, aka "suicidal headache," is so severe that many scientists believe it's the worst pain a person can experience.
Cluster headaches affect men at a greater rate than women. It occurs in series every few weeks or months. Each attack lasts from 15 minutes to 3 hours. Mostly the pain is concentrated around the eyes or behind the eye.
The exact etiology of the disease is uncertain. Pathological activity of the hypothalamus is considered to play a leading role in the development of the disease, as indirectly confirmed by the rhythmic nature of the headache episodes. Triggering factors responsible for triggering new attacks are individual for each patient.
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WHY do launch vehicles fly exclusively in an arc?
Launch vehicles are started on an arc-shaped trajectory to get the spacecraft into orbit properly. At the first stage, the spacecraft moves upwards, overcoming air resistance, and when above 100 kilometers the atmosphere gets thin enough, the rocket changes its trajectory to reach the target orbit with minimum fuel consumption.
If the launch vehicle is lifted directly at an angle to the horizon, the air resistance will be stronger and there is no guarantee it can overcome it and reach a stable orbit.
Launch vehicles are started on an arc-shaped trajectory to get the spacecraft into orbit properly. At the first stage, the spacecraft moves upwards, overcoming air resistance, and when above 100 kilometers the atmosphere gets thin enough, the rocket changes its trajectory to reach the target orbit with minimum fuel consumption.
If the launch vehicle is lifted directly at an angle to the horizon, the air resistance will be stronger and there is no guarantee it can overcome it and reach a stable orbit.
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WHY does the cough intensify at night?
When a person remains in a horizontal position, mucus accumulates in the nasopharynx and the airways cannot be cleared.
With a runny nose, secretions from the nose and sinuses drain into the throat and cause a cough reflex, so the coughing is worse when we sleep, especially when turning over from side to side, and in the morning when getting out of bed.
Dust and dry air can make the cough worse. Dry and hot air irritates the mucous membranes and provokes coughing fits.
When a person remains in a horizontal position, mucus accumulates in the nasopharynx and the airways cannot be cleared.
With a runny nose, secretions from the nose and sinuses drain into the throat and cause a cough reflex, so the coughing is worse when we sleep, especially when turning over from side to side, and in the morning when getting out of bed.
Dust and dry air can make the cough worse. Dry and hot air irritates the mucous membranes and provokes coughing fits.
WHY does dizziness follow rotation in place?
When you turn your head, your eyes reflexively move in the opposite direction. It is necessary to keep the gaze on this or that object while moving. Yet, the maximum angle of eye rotation in the eye socket is small. If this angle is reached and the person keeps rotating, the eye jumps back to the central position, then turns again to the side opposite to the rotation.
After a while, the nervous mechanism providing this eye movement (it is called nystagmus) switches to a self-sustaining mode. In this case, if the rotation stops, the eyes continue to perform nystagmatic movements.
Still, the vestibular apparatus informs the brain of the immobility of the body, and this state is perceived as a rotation of the surrounding world.
When you turn your head, your eyes reflexively move in the opposite direction. It is necessary to keep the gaze on this or that object while moving. Yet, the maximum angle of eye rotation in the eye socket is small. If this angle is reached and the person keeps rotating, the eye jumps back to the central position, then turns again to the side opposite to the rotation.
After a while, the nervous mechanism providing this eye movement (it is called nystagmus) switches to a self-sustaining mode. In this case, if the rotation stops, the eyes continue to perform nystagmatic movements.
Still, the vestibular apparatus informs the brain of the immobility of the body, and this state is perceived as a rotation of the surrounding world.
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