Scientific knowledge, let you become 100,000 why

21. Why is sea water mostly blue and green? 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 reflected; when sea water is deeper, green light is also absorbed and sea water looks blue. 22. Why do you have goosebumps? There are fine hairs on surface of our skin, and under each pore there is a muscle that straightens hairs. When irritated by nerves (for example, anger, fear, cold, etc.), body temperature drops. , and hair straightening muscle will contract and cause hair to stand up, forming goosebumps. In addition to its role as isolation, this physiological system can also make an animal appear larger than it really is, thus scaring off enemy. 23. Was a seahorse born from a father's womb? Almost all animals also breed as females, but seahorse is born male. The male seahorse has an egg-hatching sac on its abdomen that resembles a kangaroo's "brood pouch", and female seahorse releases eggs into male seahorse's hatching sac. The male seahorse then takes over responsibility of breeding, and after about three weeks, a baby seahorse hatches 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 trunk and roots for storage. The green chlorophyll is missing from leaves, 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 tree's water loss, cells of stem begin to form a layer of shedding that insulates leaves from trunk after nutrients have completely left leaves, allowing leaves to fall. 26. Why do whales splash water? The whale is a mammal, but its nose does not have a shell, and its nostrils grow 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 of water 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 permanent centers together 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 and about 12,000 light-years thick at center, with 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 there in solar system? There are nine planets in solar system. This is in order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. In addition, there are many asteroids, comets and meteors in solar system, and there are 2958 officially numbered asteroids. The most famous comet is Halley's Comet. 30. How high is 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 - thunder. 32. Why can planes fly into sky? Answer: An airplane 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. When a quartz clock hanging on wall stops moving due to a dead battery, its second hand often stops at “9” position on dial. This is due to fact that second hand slows down gravitational moment most at position "9". 34. The "burning" of an 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 pot is filled with cold water, water droplets attached to outer surface of bottom of pot can only dry after being in flame for a long time, and they will not boil until dry. Since water droplets, pot and water in pot keep heat conduction, temperature is about same, as long as water in pot is not boiling, water droplets will not boil, and water droplets will gradually burn dry, evaporating on flame.Natural gas will not be expelled through a small hole on side , but only from nozzle. This is due to fact that withThe gas flow rate in nozzle is high. According to principle of fluid mechanics, flow velocity is high and pressure is low. The surface pressure of air flow is less than atmospheric pressure outside side hole, so natural gas is not emitted through small hole on side of nozzle. 37. The mirror is out of shape, farther from mirror, more out of shape. Since image in a mirror is formed by reflection from silver plated surface behind mirror, uneven silver plated surface or uneven glass thickness causes aliasing. For a non-standard mirror, farther a person is from mirror, greater deviation from normal position of reflected light on silver-plated surface, due to principle of light amplification, and greater deviation from normal position. -The shape of mirror will be. 38. Praying mantises are known as "magical insect-catching swordsmen." 39 In Uganda, Africa, there is a type of mouse that can eat cats. This type of mouse is similar to regular house mice, except that mouth has an extra layer of hard shell that is very hard. This type of mouse can emit bursts of strong odor, after cat smells it, it becomes paralyzed, trembling and unable to move. At this time, mouse jumped over, bit off cat's throat with its sharp teeth, sucked out blood, and then dragged cat to a secluded place to eat it slowly. 40. A species of munia in Amazon. When a companion unfortunately dies, other birds of same species bring colorful petals and green leaves to corpse of a companion as a “flower burial” and bow their heads one after another. 1. Condolences to deceased. 41. Why is sky red in morning and evening? In morning and evening, before and after sunrise and sunset, colorful clouds often appear in sky. 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 a source of scattered light. According to Rayleigh's law of scattering, violet, blue and blue light with shorter wavelengths in solar spectrum are most likely to scatter, 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 bottle filled with water? There are two identical glass bottles, one empty and other filled with water, and they fall to ground from same height at same timeWhich bottle is easy to break? Generally speaking, heavy bottles are easy to break. However, when bottle is filled with water, water in bottle has a different function, which can reduce deformation of bottle and make bottle less likely to break. Glass bottles break, mainly due to deformation. When an empty bottle hits ground, ground puts pressure on bottle and bottle deforms from outside to inside and finally shatters. The bottle is filled with water, and since water is incompressible, deformation is reduced, making it less likely that bottle will break. Fill bottle with water and screw cap on tightly so that it does not break. 43. Challah-flavored food is poisonous In everyday life, people often encounter food spoilage. Food spoilage is a process of decomposition and alteration of proteins, carbohydrates and fats in foods, 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 glycerol and fatty acids, and fatty acids are further decomposed to form peroxides and oxides, and then to form rancid products such as ketones and aldehydes with a special pungent odor. , namely so-called challah taste. Eating foods with an unpleasant odor due to poor marketing and long storage leads to poisoning. Clinical manifestations are mainly gastrointestinal symptoms. 44. Laughter can make people healthy because laughter can make a person's lungs expand their breathing capacity, improve blood circulation, speed up endocrine activity, increase appetite and increase digestive juices in a good mood. 45. Maple leaf The reasons why seeds turn red: one is action of anthocyanins, and other is that chlorophyll continues to decompose due to cold weather and is replaced by anthocyanins. 46. ​​Inspired by dolphins, scientists have created an underwater acoustic detection equipment - echo sounder. Including two Latin letters of genus name and species name, it is called double name method, which was first invented by Swedish scientist Linnaeus in 1758. The patterns on which name is based are called type specimens, one of which is designated as holotype, and rest as paratype. 48. Vitamin C is declining and should not be eaten with seafood. 49. New furniture usually has formaldehyde, you can put concentrated ammonia water to absorb formaldehyde50, sausages, bacon and pickles contain sodium nitrite, which under certain conditions can produce aminnitrite in the human body, which is a carcinogen.