Why do people yawn? Why does the hair turn white when people are old? Why do women live longer than men on average?
Wait a minute.
So what is the reason?
The following are ten pieces of information about the scientific knowledge around you compiled by Bian Xiao, hoping to help you.
Ten little scientific knowledge around you:
1. Why do people yawn?
When we feel tired, a lot of carbon dioxide has been produced in our bodies. When there is too much carbon dioxide, oxygen must be supplemented to balance the needs of the body. Because these residual carbon dioxide will affect our body's functional activities, then the body will send out a protective reaction, so we yawn. Yawning is a deep breathing action, which will let us breathe in more oxygen and expel more carbon dioxide than usual, and it can also eliminate fatigue.
2. Why does hair turn white when people are old?
There is a substance called melanin in our hair. The more melanin, the darker our hair will be. Without melanin, hair will turn yellow or white. When human beings reach old age, various functions of the body will gradually decline, and the formation of pigments will be less and less, so the hair will gradually turn white!
3. Why do you growl when you are hungry?
When you are hungry, you will purr. This is because the food you have eaten before has almost been digested. Although the stomach is empty, the gastric juice in the stomach will continue to secrete. At this time, the contraction of the stomach will gradually expand, and the liquid and gas inside will be stirred up and purr. Don't be embarrassed by your stomach growling next time! Because this is a normal physiological action.
4. Why does the baby cry all the time when it is born?
Babies cry when they are born, not because they are unhappy, but because they are taking the first breath of air! When babies leave their mother's body and are born, the first breath of air will rush to their throats, violently impact the vocal cords, make them vibrate, and then make a sound similar to crying.
5. Why not tickle yourself?
When others scratch ourselves, we feel itchy and laugh nonstop; However, when we scratch ourselves, we not only don't laugh, but also don't itch. Based on our psychological preparation, the brain will send out new information and the nerves will relax, so we won't laugh or itch!
6. Why do you get goose bumps?
There is hair on the surface of our skin, and there is a vertical hair muscle under each pore. When stimulated by nerve, the temperature of our body will drop, and the vertical hair muscles will contract, making our hair stand up and form goose bumps. In addition to keeping warm, this physiological system can make animals look bigger than they really are, thus scaring off enemies.
7. Why is the average life expectancy of women 5.86 years longer than that of men?
An important reason is that women comb their hair more often than men, and combing their hair more can prolong life.
The brain is the central nervous system that commands and regulates various human activities. There are twelve pairs of nerves, about 654.38 billion cells, five arteries, six kinds of lymph and 84 acupoints in the human skull. The cerebral cortex is 2-3 mm thick, with a total area of about 2,200 square centimeters. There are about 654.38 billion hairs growing, which will keep you awake and prolong your life. Combing one's hair is the most ideal project for brain exercise. Nourishing qi and blood, regulating function, enhancing secretion activity, improving blood circulation, promoting metabolism, conducting thinking channels and combing hair more can not only prolong life, but also make your face rosy and refreshed.
9. Why not one or three thumbs?
The average person has five fingers, each with a different length. However, does anyone realize that all fingers have three sections except the thumb, and only the thumb has two sections? It turns out that the number of joints is just the same as the other four fingers. If it is three knots, the thumb will appear weak, so that it can't lift heavy objects; If there is only one section, it can't grasp things freely with the other four fingers!
10. Why do eyelids jump?
Eyelid jump is caused by the stimulation of muscles around the eyes. For example, reading for a long time, sleeping less at night, conjunctival inflammation of the eyes, and strong light irritating the eyes.