Popular science knowledge 100, 50 science knowledge 50 science knowledge
1. Rabbits communicate by patting ground with their paws. Most rabbits that pat ground with their hind legs are male rabbits, which is a way of expressing their emotions to females.
2. The largest monkey in world is a baboon, and smallest is a monkey.
3. The real name of Four Different Elephants is elk, a rare animal in our country.
4. Why does sorbet smoke?
Sorbet smokes because there is a lot of invisible water vapor in outside air. When it encounters a very cold sherbet, it turns into mist and surrounds sherbet when it is cold. The sorbet seems to "breathe".
5. Why do sunflowers always face sun?
Sunflower stems contain wonderful auxin. This auxin is very sensitive to light. When it meets light, it moves to backlight side, and at same time, it stimulates cells on backlight side to multiply rapidly, so backlight side grows faster than light side, causing sunflower to produce phototropic bending.
6. Why do cicadas shed their skin?
The shell (exoskeleton) of cicada is hard and cannot expand as cicada grows. When cicada grows to a certain stage, cicada's exoskeleton restricts growth of cicada, and cicada's original exoskeleton is removed, it becomes a cicada.
7. How do bees make honey?
The bees first spit sweet juice from plucked flowers into empty hive. At night, they suck sweet juice into their honey stomachs for cooking, then spit it out and swallow it again. It takes 100 to 240 revolutions before it turns into sweet honey.
8. Why do stars twinkle?
We see twinkling stars, which is not due to a change in luminosity of stars themselves, but due to occlusion of atmosphere. The atmosphere is between us and stars. As starlight travels through atmosphere, it is affected by density and thickness of atmosphere. The atmosphere is not completely transparent, its transparency will vary with density. Therefore, when we look through it at earth at stars, we see that stars seem to twinkle.
9. Why do people snort?
When we feel tired, body produces a lot of carbon dioxide. When there is too much carbon dioxide, oxygen must be added to balance body's needs. Since these residual amounts of carbon dioxide will affect functional activities of our body, at this time body will send a defensive response, so we begin to fight. Snoring is deep breathing that allows us to take in more oxygen and exhale carbon dioxide than usual, and also eliminates fatigue.
10. Why can snakes walk without legs?
Snakes have many scales, which are outer layer of armor on their bodies. Scales are used not only to protect body, but alsomaybe their "legs". As snake crawls forward, its body takes on an S-shape. Each scale outside of S-shape will tilt upward to help snake grip rough road as it moves forward. These scales interact with snake's muscles and can cause snake's body to crawl forward so that snake can walk without legs!
11. Why does hair turn gray with age?
There is a substance in our hair called "black pigment". The more black pigment, darker hair color. And if there is not enough black pigment, hair will turn yellow or white. When people reach old age, various functions of body gradually decrease, and production of pigment becomes less and less, so hair gradually becomes white!
12. Why do fireflies glow?
Fireflies will glow because they have a light emitter at end of their abdomen, filled with a variety of phosphor luminescent substances and luminescent enzymes, so that fireflies can emit flashes of light. The purpose of glowing fireflies is not only lighting, but also courtship, warning and trapping. For them, it is also a means of communication. Different types of fireflies emit light of different shapes, frequencies and colors, and they use this to convey different messages.
13. Why do you growl when you're hungry?
When you're hungry, you'll grunt. This is because food you ate before is almost overcooked. Although stomach is empty, gastric juices in stomach will continue to flow. At this time, contractions of stomach will gradually expand, and liquid and gas inside will agitate, causing a gurgling sound. Next time, don't be embarrassed that your stomach is growling! Because it is a normal physiological action.
14. Why doesn't an ostrich fly?
A species of ostrich with a big body, but they can't fly into sky! It's not that their wings don't work, it's that their bones are too soft and their wings are too small to fly. In addition, musculature of ostrich is underdeveloped, and chest is flat, which is not conducive to flight. Ostriches live in Africa, and because they lived in desert areas for a long time, their bodies gradually evolved into what they are today to adapt to their environment.
15. Why doesn't food in a tin go bad?
Meat for lunch, roach in black bean sauce, tomato sauce... all of these are delicious preserves that can be stored for a long time without spoiling. This is because jars are sealed so bacteria cannot get inside. When canned food is made, all air is sucked out of jar, and then it is sealed. In absence of air, even if food inside is colored by a small amount of bacteria, they cannot survive or reproduce!
16. Why do newborn babies cry non-stop?
Babies wheeze when they're born, not because they're unhappy, but because they're taking their first breath of air! When babies are born away from their mother's body, first breath thatand they inhale, rush down throat, hitting vocal cords hard, causing them to vibrate and make a sound similar to crying.
17. Why does a lizard keep jumping after its tail is broken?
To protect themselves, many lizards also use camouflage colors to cover their eyes; when some lizards are attacked, their tails break due to strong muscle contraction. Due to fact that some nerves are still alive in broken tail, it will continue to bounce, thereby distracting enemy so that he can escape. Do not think that their life will end this way, in fact, it only takes a few months for tail to grow back and continue to live.
18. Why does pine mouse have such a big tail?
Don't look at light mouse tail! While pine ear is jumping up and down tree, its tail is doing a lot of work. He can balance pine clam while jumping on tree to avoid falling and getting injured. In addition, this large tail can play a more protective role in winter, and it is convenient and practical to wrap tightly around body of pine tree.
19. Why can't a person's thumb have one or three knots?
The average person has five fingers, and length of fingers can vary. However, has anyone noticed that, in addition to thumb, other fingers also have three joints, and thumb has only two joints? .. It turns out that its number of joints exactly matches other four fingers. If there are only three joints, thumb will appear weak so that it cannot lift heavy objects; if there is only one joint, it won't be able to cooperate with other four fingers to grasp objects freely!
20. Why don't you feel itchy when you scratch?
When others scratch us, we feel itchy and constantly laugh; however, when we scratch ourselves, not only do we not laugh, but we do not feel itchy either. Based on our mental preparation, brain will send message "no danger" and nerves will relax accordingly, so we won't laugh and feel itchy!
21. Why is sea water mostly blue and green?
When looking at sea, I often find that sea water is blue-green. However, when you scoop up sea water, all you see is that it is as clear and colorless as water was in past. It turns out that sea water itself is not much different from water that we come into contact with every day, and it is also transparent. The green color we see is actually a phenomenon caused by ability of seawater to absorb light. Only green light can be absorbed by seawater and thus reflected; when sea water is deeper, green light is also absorbed and sea water looks blue.
22. Why do you have goosebumps?
There are sweat hairs on surface of our skin, and there is a rectus muscle under each eye opening. When nerves are irritated (for example: anger, fear, cold andetc.) body The temperature drops and erector muscle contracts, causing hair to stand on end, forming goosebumps. In addition to role of isolation, this physiological system can also make an animal appear larger than it really is, thereby repelling enemy.
23. The seahorse was born from womb of father?
Almost all animals reproduce females, but seahorses are unusual in that they are born males. The male seahorse has a pouch-like incubation sac on its abdomen, and female seahorse releases eggs into male seahorse's incubation sac. Thereafter, male seahorse takes over responsibility of breeding, and after about three weeks, baby seahorse is ejected from father's body.
24. Why do leaves change color?
The reason leaves change color is due to chemical they contain, chlorophyll. When autumn arrives, days are shorter and temperatures are cooler than in summer, so leaves stop producing chlorophyll and remaining nutrients are transported to trunks and roots for storage. The leaves lack green chlorophyll and at same time other chemical pigments appear, so we see more yellow and brown leaves.
25. Why are there fallen leaves?
When autumn comes, more water evaporates from leaves than in summer, but roots absorb less water than in summer. To reduce water loss of tree, stem cells begin to form a separating layer, after nutrients are completely gone from leaves, separating layer isolates leaves from trunk, and leaves fall off.
26. Why do whales splash water?
The whale is a mammal, but its nose does not have a shell, and nasal opening grows on top of its head. Living in water, it breathes with lungs that can store a lot of air at a time, so it doesn't need to go to surface of water often to breathe. But when he comes to surface to breathe, he breathes through his nose, and loud sound waves that are emitted from body when breathing are caused by pressure.
27. How big is Milky Way? Many constants combine to form a huge galaxy, and galaxy in which solar system is located is called Milky Way. The Milky Way is like a large disk, about 80,000 light-years wide, about 12,000 light-years in center, and a total of over 1,000 stars.
28. Why can't I see stars during day?
Because some of sunlight is scattered by gas and dust in atmosphere during day, sky is very brightly lit, and light emitted by sun is very strong, so we cannot see stars.
29. What celestial bodies are in solar system? There are nine planets in solar system. These are in order: Mercury, Venus, Earth, Mars, Mars, Mars, Uranus, Neptune and Pluto. In addition, there are many asteroids, comets and meteors in solar system, and there are 2958 officially numbered asteroids.ometa - Halley's comet.
30. What is height of blue sky?
The "blue sky" is actually Earth's atmosphere. The atmosphere surrounds earth's air, which is divided into 5 layers according to air density, and has a total thickness of 2000-3000 kilometers. But most of air is concentrated from ground below 15 kilometers, and higher you go, thinner air becomes. What a dense atmosphere, how high must be blue sky.
31. What happened to thunder?
Answer: It is a natural phenomenon when negative and positive electricity meet together. When it rains, some clouds in sky are positively charged and some are negatively charged. When two kinds of clouds meet together, they discharge and emit very bright lightning. At same time, they radiate a lot of heat. , due to which surrounding air quickly heats up, expands and makes a loud noise, that is, thunder.
32. Why can planes fly into sky?
Answer: The plane has two wings, like a bird, and it also has propellers. Wings can generate lift to keep aircraft in air, and propellers can generate power to push aircraft forward. Therefore, plane can take off into sky like a bird.
33. The second hand of quartz clocks hanging on wall often stops at "9" position on dial when battery is low and stops moving. This is because second hand is hindered most by gravity at 9 position.
34. The "burning" of electric furnace is conversion of electrical energy into internal energy, and does not require oxygen. Oxygen can only oxidize electric furnace wire and shorten its service life.
35.When filling a saucepan with cold water, water droplets adhering to outer surface of bottom of saucepan may burn for a long time on flame, and it will not boil until it boils. This is because water drops, pot and pan The water in pot maintains heat conduction, and temperature is about same As long as water in pot does not boil, water drops will not boil, and water drops will gradually burn out, evaporating on flame
36. There are several small holes on side of gas stove nozzle that communicate with outside world, but natural gas will not be emitted through small holes on side, but only from nozzle. This is due to fact that nozzle is natural. The gas flow rate is high. According to principle of fluid mechanics, flow rate is high and pressure is low. The surface pressure of airflow is less than atmospheric pressure outside side port, so natural gas will not spray through small port on side of nozzle.
37. Mirror with same face, farther you are from mirror, bigger face will be. Since image in a mirror is formed by reflecting silver plated surface behind mirror, an uneven silver plated surface or uneven glass thickness will create irregularities. For a homogeneous mirror thanthe farther away a person is from mirror, greater deviation from normal position of reflected light on silver-plated surface will be due to principle of light amplification, and more uniform mirror will be.
38. The praying mantis is called "catcher of gods"
39. In Uganda, in Africa, there is a species of mice that can eat cats. This type of ear is similar to that of common house mouse, except that there is an extra layer of hard shell in mouth, which is very hard. Such an ear can emit bursts of strong smell, after cat sniffs it, it becomes paralyzed, trembles and cannot move. At this point, mouse jumps over, bites cat's throat with its sharp teeth, sucks out blood, and then drags cat to a secluded place to eat it slowly.
40. A species of mouse bird in Amazon, when its companion sadly dies, other members of same species bring colorful petals and green leaves to their companion's corpse as a "flower burial" for him. Just lower your head to express your condolences to dead.
41. Why is sky red in morning and evening? In morning and evening, before and after sunrise and sunset, colorful clouds often appear on horizon. The formation of morning glow and sunset glow is due to scattering effect of air on light. When sunlight enters atmosphere, it collides with atmospheric molecules and particles suspended in atmosphere and is scattered. These atmospheric molecules and particles do not themselves emit light, but because they scatter sunlight, each atmospheric molecule forms scattered light
Source. According to Rayleigh's law of scattering, violet, blue and blue light with shorter wavelengths in solar spectrum are most easily scattered, while red, orange and yellow with longer wavelengths have a high transmittance. Therefore, we see that clear sky is always blue, and light above horizon is only yellow, orange and red light with a longer wavelength. After light is scattered by impurities such as air molecules and water vapor, sky becomes colorful.
42. Why is it hard to break a water bottle?
Two identical glass bottles, one empty and other filled with water, are simultaneously thrown from same height onto ground. Which bottle is easier to break? Generally speaking, heavy bottles are easy to break. However, when bottle is filled with water, water in bottle performs another function that can reduce deformation of bottle, which in turn makes bottle less likely to break. Glass bottles break, mainly due to deformation. When an empty bottle hits ground, ground presses on bottle, bottle deforms from outside to inside and finally breaks. The bottle is filled with water, and since water is incompressible, deformation is reduced, making it less likely that bottle will break. Fill bottle inmilk and then screw on lid, it will be harder to break.
43. Hara-flavored food is poisonous In everyday life, people often encounter food spoilage. spoiled food
This process is process of decomposition and alteration of proteins, carbohydrates and fats in food, and its degree depends on type of food, type and number of microorganisms and environmental conditions. Usually fat spoilage is mainly due to rancidity, which is a kind of mutagenic food contamination. Enzymes, ultraviolet rays and oxygen produced by microorganisms can decompose neutral fat in food into oil and fatty acids, and fatty acids further decompose to form peroxides and oxides, and then release special irritating gases. Rancidity products such as ketones and aldehydes make up so-called Hara flavor. The use of non-marketable and long-stored products with an unpleasant odor can lead to poisoning. Clinical manifestations are mainly gastrointestinal symptoms. Some patients may experience dizziness, headache, bloating, diarrhea, abdominal pain, nausea and vomiting, and other symptoms .
44. Laughter can make people healthy, because laughter can make a person's lungs expand their breathing capacity and improve blood circulation: accelerate endocrine activity, happy emotions increase appetite and increase digestive juices.
45. The reason why maple leaves turn red is because one of them is action of anthocyanins, and other is that chlorophyll is continuously decomposed due to cold and is replaced by anthocyanins.
46. Inspired by dolphins, scientists have created an underwater acoustic detection device - an echo sounder
47. Nomenclature and type specimens of organisms: Scientists give a Latin scientific name to every organism they have studied but not registered, including two Latin characters for genus name and species name, which are called double names. first invented by Swedish scientist Linnaeus in 1758. The specimens on which nomination is based are called type specimens, with one of them designated as holotype and rest as hypotypes.
48. Vitamin C is declining and should not be eaten with seafood.
49. New furniture usually contains formaldehyde, you can put concentrated ammonia to absorb formaldehyde
50, sausage, salted meat and pickles contain sodium nitrite, which under certain conditions can form aminonitrite in the human body, which is a carcinogen
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