1. Why the stars will flash flash it?
We see stars sparkle, this is not because the stars change their brightness, but with the atmosphere, blocking the.
Across the atmosphere between us and the stars, when the starlight through the atmosphere, they will receive the impact of atmospheric density and thickness. The atmosphere is not absolutely transparent, its transparency will be different according to the density difference. Therefore, we look at the stars on the ground through it, you'll see the stars as if flashing the same again.
2. Why do people yawn?
When we feel tired, the body has generated a lot of carbon dioxide. When the excess of carbon dioxide, it is important to increase the oxygen needed to balance the body. Because these residual carbon dioxide, would affect the functioning of our body activity, then the body will issue a protective response, so come on playing yawn.
Yawning is a kind of deep breathing movements, it makes us more than usual, sucked into oxygen and emit carbon dioxide, but also do it to eliminate the role of fatigue.
3. Why are snakes able to walk without feet?
The snake's body there are many scales, which is the outermost layer of their body armor. Scale is not only used to protect the body, can also be their "feet."
Snake crawling forward, the body will be showed S-shaped. And every one in the S-shaped outside of the scales will tilt to help the snake move forward to seize the uneven road surface. The scale of muscle co-ordination with the snake, and can push the body forward in crawling, so the snake can move without legs呀!
4. Why do sunflowers bloom is always toward the sun,
Sunflower chrysanthemum stems the following places, contains something called "plant growth hormone," substances. This material is accelerating function of reproduction, but it has a repulsive optical activity, when confronted with the light, they will go to the backlight side.
Therefore, when the sun rises, sunflower stems will immediately hide backlight side to go on the whole plant looks toward the direction of the sun was bent.
5. Why does a person old hair will be white?
Our hair had something called "melanin" in substance, the more melanin the more black hair color. The melanin small, yellow or white hair will be issued. Humans in old age, the body's various functions will gradually decline, pigment formation will be less and less, so the hair will gradually become white ah!
6. Why is Firefly will shine?
Firefly will be light because in the end of their abdomen are light-emitting devices, light-emitting device filled with a number of quality and light-emitting light-emitting phosphorus-containing enzymes, so that can be issued a flash of fireflies flash of light.
The purpose of firefly light, in addition to lighting, there are mating, warning, trapping and so on. This is also a communication tool for them, different types of fireflies light-emitting means emitting frequency and the color will be different, they like to take this to convey a different message.
7. Why are hungry will cluck call?
She was hungry and rolling will be called, it is because the food prior to eating fast to digest finished, although the empty stomach, but will continue to secrete gastric juice the stomach. At this time the contraction of the stomach will gradually expand inside the liquid and gas will be welling up, resulting in rolling sound.
Next time should no longer stomach the embarrassment of cuckoo called ah! Because this is a normal physiological actions do.
8. Why does an ostrich does not fly?
Body type of a large ostrich class, but they do not fly overhead, and ah! This is not because their wings do not work, but their feathers are too soft, wings too small, not fit for flying. In addition, the ostrich muscles developed, sternum flat again, and on the flight did not help.
Ostriches live in Africa, due to the long living in desert areas, the body in order to adapt to the environment, they gradually evolved into what it is.
9. Why is not perishable and canned food inside?
Luncheon meat, lobster sauce dace, tomato sauce, canned beans ...... are delicious food, they can be stored for a long time are not easily deteriorate. This is because canned food is sealed, the bacteria can not enter.
People in the manufacture of canned food, when the canned air in all out, and then seal it. In the absence of air case, even if some bacteria inside the food from being contaminated, they can not survive or breed ah!