ontent='width=device-width, initial-scale=1' name='viewport'/> 12 things are very familiar but not sure you know why

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12 things are very familiar but not sure you know why

Cập nhật: 17 thg 6, 2019 lúc tháng 6 17, 2019

There are many familiar things happening in life that you don't know why. 
Below is the answer to some of the things you still have to ask.
1. Why are we goosebumps?
This is a physiological phenomenon originating from ancient animals.  

It is a phenomenon where tiny spots rise on the skin that look like bumps after being plucked. These nodules come from muscle contraction attached to each hair. Each muscle contraction creates a shallow depression on the surface of the skin, thus causing the surrounding area to rise. Simultaneous contraction also causes hairs to stand up. 

For animals, the hair that builds up expands the air that holds the heat around the body to help them warm up faster. In the event of a threat, this phenomenon also helps them look bigger and scary in front of the enemy.  

In humans, the cause of this reaction is the body that unconsciously releases the hormone adrenaline. This hormone not only causes muscle contraction but also affects the body's response. It usually occurs when we are cold or afraid, stressed or have strong emotions like anger or excitement. 

2. Why is our voice different from the phone or recording?
Most of us feel puzzled when listening to our voices through recordings, answering machines. So why is there such an extraordinary difference?  

The explanation for this difference is that when we say, the sound will be transmitted in two completely different directions: 

One is the sound transmitted in the air to the ears of others, they must pass through the outer ear, continue to the eardrum and finally their inner ear. This is the same as when recording your own voice.  
Another direction is the sound when we say it out loud, which will be played from the vocal cords, run through the pharynx and then transmitted to the skull and inner ear, so only you can listen to the sound clearly. 
In addition, when the sound is transmitted in the air, it will be influenced by the elements in the air, causing the energy to be reduced and the tonality to change quite a lot. Conversely, in the process of transmitting sound directly to the skull, there will be less energy and timbre loss.

3. Why do we have headaches when eating or drinking cold food?
The reason is that when the food or drink is too cold through the throat, it will quickly stimulate the mucous membranes and sensory organs, controlling nerve endings, blood vessels to the brain ..., especially the brain region. The former is stimulated locally, causing it to contract, while the blood vessels in the brain relax more than usual (almost cortical pressure).  

The sudden increase in cerebral blood vessels will cause headaches such as a seizure ... causing headaches, nausea, especially in the temples and forehead.

4. Why does our skin become darker and hair becomes brighter in the sun?
In both cases, the sun will break down the melanin pigment and affect our hair color and skin color.  

When this pigment breaks, the hair does not replenish melanin, which makes them look brighter.  

For the other skin, at this time, the skin "responds" to the sun by producing a hormone that binds to melanin-producing cells, from which more melanin is produced. This makes the skin look darker.

5. Why is it so slow for a child to travel slowly?
Have you ever seen time pass slowly and wish you had grown so fast?  

A child often has to remember more events than us. When babies, they begin to get used to the world around them, and their memory must record a lot of data. Hence a year of a child contains more data than adults.  

For a specific comparison, it can be said that a week of a child is a very big part of the time after they mature.

6. Why are eyes not cold?
The main reason is that in our eyes only the nerves are in charge of touch and feeling without the sensation of cold sensation. So no matter how cold the weather is, our eyes don't feel cold.   

Besides, the largest part of the eyeball is inside the skull and it is warmed by the blood flowing inside.

7. Why is the white dust on a white background on a black background, then the dust is black?
In fact, dust is gray. However, because of their small size, we cannot recognize their true colors.  

On a black background, these dust particles are brighter so we see them white, and on a white background they are darker so we see them black. 

8. Why do birds fly in an inverted V shape in the sky?
This is a way to help them save energy. The leading flying birds create a special vortex of air by their wings. This helps the birds fly behind will be less affected by air resistance and save more energy.  

At the same time, flying in an inverted V pattern helps each member of the herd always see the leader and follow it.

9. Why is the sound of stream sounding ragged?
This happens when air bubbles are swept into the water stream and then burst. It creates a lot of different sounds that we call "tearing."

10. Why do we get motion sickness?
Motion sickness is because the brain is mistakenly sent up by eyes and vestibular signals (which are two bodies that determine balance for humans). When sitting in the car, the eyes see everything balanced by the particular ability to self-eliminate the confounders so "informed" to the brain that the person is balancing. While the vestibule senses the shaking of the car and sends it to the brain so that the brain controls the body to balance itself against shaking. After the long process of brain disorder, information leads to car sickness.  

Then, the brain remembers those cases, leading to people who think of cars as intoxicated. Or just smell the car is drunk.

11. Why are ring fingers often used for blood tests?
Thumb and little finger attached to our wrist. If unfortunately you have an infection, it can spread to your whole arm. Therefore, doctors often advise to take blood from all fingers except for the thumb and pinkie.  

However, the ring finger will be the least painful. It works less and has skin thinner than other fingers. If you don't use this finger often, it will heal quickly. 

12. How does the toilet on the plane work?
The toilet on the plane is not flooded like the common toilet we use today. Once you "finish" and press discharge, the system will activate the "product" suction function to clean the toilet. Waste will be transferred into a large tank, located at the aircraft's ground.   

When landing, this waste will be treated. There is a dedicated vehicle to handle this task, which is the truck.