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And why? .. 10 odd responses to questions that were asked at least once every
Editorial - the biggest 'Who Knows? "You'll ever need, because in order to learn new facts, one must first ask the question" why? .. "Here are 10 answers to" why ", which at least once each interested cheloveka.1. Why do aircraft have ashtrays, no smoking again? 
Ashtrays are available not only in the older models, but also completely new aircraft are equipped with them. Why? ..
The answer is that despite the fact that smoking is strictly prohibited in the plane set fire alarm, some people will still be smoking. And it is better to give the bully an ashtray than let him burn the plane. In aviation, the risk is unacceptable.
2. Why do the books have blank pages? 2,494,441
Many books are often published with a one-two blank pages, sometimes even more. This is a result of the printing process. Pages of books are usually printed on very large sheets of paper, not on the individual cut sheets. Machines folded and cut paper pages, but the product may not entirely share exactly eight, hence the appearance of blank pages.
3. Why do people sneeze when they look at a bright light? 17,048,446
Most often, sneezing is a result of irritation of the nasal mucosa. However, in the case of so-called "light reflex ptarmic" sneeze it is simply when you look directly at the light source.
Apparently, ptarmic light reflex - a "glitch", the result of the intersection of nerves in the brain. The optic nerve, perceiving the light is located next to the trigeminal nerve, responsible for sneezing. When the optic nerve sends electrical impulses to the brain, the signal touches the trigeminal nerve, causing the brain to believe that the nose was irritated, and an urgent need to sneeze.
4. Why hair turns gray? 2,604,903
Hair get their natural color thanks to the pigment cells called melanocytes under. Melanocytes produce chemicals that transmit black, dark brown, red and yellow melanin cells, creating the main ingredient of hair - keratin. As people age, melanocytes are destroyed, because of which the keratin pigment gets smaller - because of hairs become gray. Eventually, the cells cease to function and the hair is no longer getting the pigment becomes completely white.
5. Why did the entrance to the store you blown air? 35,521,765
Quite often at the entrance to the store or mall shoppers meets a stream of air. It is - "air barrier" which supports one temperature in the building and preventing penetration of the air outlet. This is especially useful if you have to keep the door open all the time. Also it makes excellent air barrier against the entry of insects and debris from entering the building through the turbulence.
6. What causes the "butterflies in the stomach"?
A sense of awe in the intestine caused by strong emotions, such as fear, the experience, the WHO * uzhdenie. This feeling is due to the so-called "gastro-brain axis." The brain interprets emotions such as stress and responds to it, producing adrenaline to help you cope with the threat or run away from it. Adrenaline causes blood flow to the heart and muscles, as well as the amount of blood in the human body is limited, its outflow from other organs such as the intestine, leads to that same "feeling butterflies»
7. Why is alcohol burns? 19,993,127
When alcohol reaches the cut, it acts directly on the VR1 receptors in the skin that are responsible for the perception of heat. Typically they are activated at high temperatures, but alcohol reduces their sensitivity threshold to body temperature. Receptors "think" that the body burn, and they transmit the pain signal to the brain, despite the fact that the skin was not damaged.
8. Why is brushing your teeth after meals seems hostile? 83,512,482
This stems from the foaming agent used in most toothpastes. Sodium lauryl sulfate reduces the taste buds responsible for the perception of sweet taste.
Furthermore, sodium lauryl sulfate destroys phospholipids which usually reduce bitterness. Therefore, all the sweets that you eat after brushing, will not seem sweet, bitter and everything will be doubly bitter.
9. Why is the sky blue? 47,759,891
White light from the sun hits the oxygen and nitrogen molecules that make up most of the Earth's atmosphere, and is scattered, creating color. However, since the wavelength shorter than the other blue, the color is dispersed more.
This effect also explains how the sky come from other colors. Closer to the horizon, the sky becomes a much paler because the light passes through more air and dissipates more rapidly mixing with other colors and losing its blue color.
10. Why is it so difficult to remember dreams? 36,128,990
The conditions in which is the brain during REM sleep, when most dreams, do not allow to move them into long-term memory. It also plays the role of the lack of the hormone norepinephrine: this hormone plays an important role in memory, but is not produced during sleep. Yes, and the hippocampus - "device" of the brain responsible for memory, the dream is not available to solve other problems. We do not remember dreams simply because the mechanism of memory is turned off.
via factroom.ru
Ashtrays are available not only in the older models, but also completely new aircraft are equipped with them. Why? ..
The answer is that despite the fact that smoking is strictly prohibited in the plane set fire alarm, some people will still be smoking. And it is better to give the bully an ashtray than let him burn the plane. In aviation, the risk is unacceptable.
2. Why do the books have blank pages? 2,494,441
Many books are often published with a one-two blank pages, sometimes even more. This is a result of the printing process. Pages of books are usually printed on very large sheets of paper, not on the individual cut sheets. Machines folded and cut paper pages, but the product may not entirely share exactly eight, hence the appearance of blank pages.
3. Why do people sneeze when they look at a bright light? 17,048,446
Most often, sneezing is a result of irritation of the nasal mucosa. However, in the case of so-called "light reflex ptarmic" sneeze it is simply when you look directly at the light source.
Apparently, ptarmic light reflex - a "glitch", the result of the intersection of nerves in the brain. The optic nerve, perceiving the light is located next to the trigeminal nerve, responsible for sneezing. When the optic nerve sends electrical impulses to the brain, the signal touches the trigeminal nerve, causing the brain to believe that the nose was irritated, and an urgent need to sneeze.
4. Why hair turns gray? 2,604,903
Hair get their natural color thanks to the pigment cells called melanocytes under. Melanocytes produce chemicals that transmit black, dark brown, red and yellow melanin cells, creating the main ingredient of hair - keratin. As people age, melanocytes are destroyed, because of which the keratin pigment gets smaller - because of hairs become gray. Eventually, the cells cease to function and the hair is no longer getting the pigment becomes completely white.
5. Why did the entrance to the store you blown air? 35,521,765
Quite often at the entrance to the store or mall shoppers meets a stream of air. It is - "air barrier" which supports one temperature in the building and preventing penetration of the air outlet. This is especially useful if you have to keep the door open all the time. Also it makes excellent air barrier against the entry of insects and debris from entering the building through the turbulence.
6. What causes the "butterflies in the stomach"?
A sense of awe in the intestine caused by strong emotions, such as fear, the experience, the WHO * uzhdenie. This feeling is due to the so-called "gastro-brain axis." The brain interprets emotions such as stress and responds to it, producing adrenaline to help you cope with the threat or run away from it. Adrenaline causes blood flow to the heart and muscles, as well as the amount of blood in the human body is limited, its outflow from other organs such as the intestine, leads to that same "feeling butterflies»
7. Why is alcohol burns? 19,993,127
When alcohol reaches the cut, it acts directly on the VR1 receptors in the skin that are responsible for the perception of heat. Typically they are activated at high temperatures, but alcohol reduces their sensitivity threshold to body temperature. Receptors "think" that the body burn, and they transmit the pain signal to the brain, despite the fact that the skin was not damaged.
8. Why is brushing your teeth after meals seems hostile? 83,512,482
This stems from the foaming agent used in most toothpastes. Sodium lauryl sulfate reduces the taste buds responsible for the perception of sweet taste.
Furthermore, sodium lauryl sulfate destroys phospholipids which usually reduce bitterness. Therefore, all the sweets that you eat after brushing, will not seem sweet, bitter and everything will be doubly bitter.
9. Why is the sky blue? 47,759,891
White light from the sun hits the oxygen and nitrogen molecules that make up most of the Earth's atmosphere, and is scattered, creating color. However, since the wavelength shorter than the other blue, the color is dispersed more.
This effect also explains how the sky come from other colors. Closer to the horizon, the sky becomes a much paler because the light passes through more air and dissipates more rapidly mixing with other colors and losing its blue color.
10. Why is it so difficult to remember dreams? 36,128,990
The conditions in which is the brain during REM sleep, when most dreams, do not allow to move them into long-term memory. It also plays the role of the lack of the hormone norepinephrine: this hormone plays an important role in memory, but is not produced during sleep. Yes, and the hippocampus - "device" of the brain responsible for memory, the dream is not available to solve other problems. We do not remember dreams simply because the mechanism of memory is turned off.
via factroom.ru
