1. Shorter popular science knowledge for primary school students
Technology knowledge
Plug knowledge
Why electric fans, washing machines, refrigerators Most household appliances use three-wire plugs? What is the difference between a three-wire plug and a three-phase plug?
Three-phase electrical appliances refer to three different live wires. The voltage between each two wires is 380 volts. They are generally used in power systems, mostly in industrial electricity. Household appliances generally use single-phase power supply. Its three wires are live wire, neutral wire (neutral wire) and ground wire. The voltage between the live wire and neutral wire is 220 volts, so this is not three-phase electricity. Its plug And sockets are not three-phase plugs and three-phase sockets. The ground wire is for safety.
Fruits with antihypertensive effects
Hawthorn; Hawthorn can dilate blood vessels, lower blood pressure, and lower cholesterol. You can choose 10 wild hawthorns (preferably fresh), mash them and add 30 grams of sugar, decoct them in water and take them regularly. They have good blood pressure lowering and stomach strengthening effects.
Banana; Banana contains a variety of vitamins, can clear away heat and lower blood pressure, and can be eaten regularly. It is also effective to use 30 to 60 grams of banana peel or fruit stem, decoction and take it. If possible, take an appropriate amount of banana flower decoction in water for better curative effect.
Water chestnuts have the effect of clearing away heat and lowering blood pressure. You can use 30 to 60 grams each of fresh water chestnuts (wash and remove mud) and jellyfish (wash off salt), make soup, and take it three times a day. It can both lower blood pressure and resolve phlegm and relieve cough.
Pineapple: Regular consumption of pineapple can enhance the hydrolysis of fibrin in the body, improve blood circulation, and eliminate edema and inflammation in patients with hypertension, edema, and thrombosis.
Black plum: rich in citric acid, malic acid, and succinic acid. For patients with high blood pressure, dizziness, insomnia, and difficulty falling asleep at night, 3 ebony plums can be stewed in boiling water with an appropriate amount of rock sugar and taken. It has the effects of lowering blood pressure, sleeping, clearing away heat and promoting body fluids.
Apple: Contains 10 nutrients including malic acid, citric acid, vitamins A, B, and C. Regular consumption of apples can improve vascular sclerosis.
5 tips on scientific milk drinking
Drinking milk is good for health, but many people still have some misunderstandings about drinking milk. Nowadays, Introduce some common sense about drinking milk scientifically.
1. It is not advisable to drink milk on an empty stomach in the morning. Because the gastrointestinal peristalsis of the human body is fast when the human body is fasting, the nutrients in milk often enter the large intestine in a hurry without being absorbed. In addition, it is not advisable to drink milk in large gulps, because this will reduce the chance of mixing with saliva in the mouth, which is not conducive to digestion and absorption. It is best to eat some biscuits, pastries, etc. before drinking milk, or drink milk while eating snacks.
2. Drinking milk at night is more beneficial. Scientific research has found that calcium metabolism in the human body has a special law: at night, especially at midnight, the plasma calcium content will reach a "trough", forcing the body to use a regulatory mechanism to transport calcium from some bones to supplement it. In this way, although the calcium in the blood is temporarily maintained, the calcium in the bones is reduced. Milk is rich in calcium, so drinking a glass of milk before going to bed can compensate for the body's need for calcium at night.
3. Milk should not be boiled with sugar. Milk is rich in amino acids. Under high temperature conditions, lysine in milk reacts with sugar to form a new compound, fructosyl amino acid. This substance not only cannot be digested and absorbed by the human body, but affects human health. It is best to drink milk fresh. If it is too cold, just heat it slightly.
4. If you don’t like milk, you can drink yogurt. People who are "averse" to milk mostly suffer from lactose intolerance. These people can try drinking yogurt. The lactose content in yogurt is greatly reduced, but almost all the nutrients of milk are retained. The lactic acid bacteria in the yogurt can survive and reproduce in the human body, which is beneficial to the absorption and utilization of nutrients and improves immunity. Yogurt does not contain antibiotics and is easy to digest and absorb, so it can be consumed on an empty stomach.
5. Yogurt cannot be heated for drinking. Drinking yogurt mainly consumes its nutrients and live bacteria. If the yogurt is heated, the human body can only drink nutrients but lose the biologically active lactic acid bacteria, so do not drink it after heating. 2. Keep the popular science knowledge short and write a few more
Insects Harmful to Humans I. Dangers of Cockroaches Cockroaches are also called oil-stealing women, sweet ladies, slippery insects..., there are many kinds of them. In the diverse insect society, its official name is cockroach.
This is a global insect, widely distributed in the five continents and four oceans of the world, especially in the tropics.
They can be found everywhere in our country….
Cockroaches have a flat body, brown, brown-black, brown, or yellowish-brown, with a metallic luster. There are two slender antennae in front of the head, emitting bursts of unpleasant odor. Usually, in addition to setting up camp and stealing food in homes, canteens, hotels, hospitals, warehouses, and shops, most cockroaches appear in fields, forests, factories, farms, and even ocean-going ships, warships, and airports, damaging trees, corn, and sugar cane. , livestock and poultry... dozens of agricultural and forestry crops, cloth, clothing, groceries, etc., causing economic losses to humans.
Cockroaches feed on dozens of household foods. Particularly fond of starch, sugar, vegetables, and foods with high humidity.
In addition, it also likes to eat dozens of Chinese medicinal materials such as Poria, chrysanthemum, and angelica, feces, and phlegm juice. The corpses of rotting small animals are also its delicacies. When you are really helpless, you can chew the paste on the edge of the book and bite the pages; even the refill of the red and blue pencil can temporarily satisfy your hunger and sustain your life.
In addition, they often bite off clothes, get into radios and televisions, bite off the coverings of wires, and even bite the nails and eyelashes of babies. They often excrete a lot of dirt in places where they have crawled and fed. Dirty feces, leaving a disgusting stench. Hence the hatred among people.
Cockroaches are vectors of many human diseases. Cockroaches are known to carry more than a dozen epidemic bacteria such as typhoid bacilli and dysentery bacilli.
It is reported that the number of bacteria in each cockroach’s antennae, feet and stomach can be as high as 13,370. In addition, cockroaches also carry human parasite eggs such as hookworms, roundworms, and flagellates. They can contaminate food and spread diseases through contact, feeding, and excretion of feces.
In recent years, there have been rumors at home and abroad that the feces of the American giant cockroach has carcinogenic effects. However, it is worth mentioning that although cockroaches as a whole are enemies of humans.
But there are also types that are beneficial to people in its camp. We must protect and use them.
For example, there is a kind of cockroach called "Chinese true ground turtle". Its female is the famous Chinese medicine "earth turtle". It is salty in taste, cold in nature and poisonous. It has the effect of breaking blood, removing gangrene and dispersing stagnation, and is mainly used to treat blood stagnation. ;Amenorrhea and bruises and other diseases. There are monographs on such species at home and abroad, and they are raised by specialized units or households.
As a sanitary pest, cockroaches are very harmful to human beings. Health organizations and epidemic prevention departments in many countries in the world regard them as objects to be eliminated, and invest a lot of manpower, material resources, financial resources, and work on them. Research on classification, living habits, environmental ecology, prevention and utilization, etc. II. Types of Cockroaches Most people think that all cockroaches they see are one kind.
In fact, there are no less than 10,000 species of cockroaches in the world. More than 6,000 of them have been studied by scientists and have scientific names.
There are more than 200 species recorded in our country. Cockroaches, although there are so many types, are so widely distributed.
But the cockroaches that are closely related to human livelihood are probably mainly cockroaches that live indoors. As for indoor cockroaches, as early as 1095, Li Shizhen had such a record: "Today, there are very many under the wall stove of people's homes, and some even gather into hundreds. Their bodies are like silkworm moths, with red belly and back, two wings that can fly, and they like light." , its smell is very smelly."
If you observe carefully, you will find indoor cockroaches, some big and small, some with long wings and some with short wings. The large and broad pronotum covering the head and chest. Some are pitch black, some have two brown vertical bands on them, some are composed of spots or patterns, and some are uneven... All these signs clearly indicate that they are not the same species. Therefore, their external forms are very different.
Current research points out that there are dozens of species of indoor cockroaches. Different parts of our country are different. The most common ones are: American giant cockroach, black-breasted giant cockroach, Australian giant cockroach, Japanese giant cockroach, spotted cockroach and German small cockroach.
III. A long history. Looking at the family tree of cockroaches, we will be surprised to find the family history of cockroaches. American scientists used C14 to test two cockroach fossils and determined that they are 300 million years old.
What a long time it has been! At that time, dinosaurs had not yet appeared, but cockroaches were already subjects of the earth. They had experienced the vicissitudes of the world and fought tenaciously with nature to survive.
What is even more unbelievable is that the cockroaches 300 million years ago are so similar in shape to the cockroaches that exist today, and the mutation is so weak. It makes people sigh: How tenacious the cockroaches are! No wonder it is known as the "living fossil of insects".
IV. Biological learning ability. It usually takes half a year to more than four years for a cockroach to complete a life cycle from egg to nymph to adult. Although indoor cockroaches have wings, they are not very good at flying. Perhaps in order to escape capture when stealing, they have developed three pairs of "scuds" and are very good at running and crawling.
If there were a race in the world of insects, they would definitely dominate the competition and win the gold medal. They are probably ashamed of their shameful sneaking behavior. They are always afraid of the light. They live in seclusion during the day and hide in dark corners, such as on the walls of sewers, around kitchen stoves, between boxes and wood, in clothes, in the pages of books... and only come out at night. Groups come out to move around and get food.
Interestingly, their eggs are laid in a leathery egg sheath, which is shaped like an old lentil and often has ring patterns on it if you look closely. There are a dozen to dozens of eggs in this carefully crafted tent.
Usually the female can lay fourteen or five egg cases in her lifetime. Some "mothers" are so afraid that their children will be invaded by foreign enemies before they hatch, that they always hang the egg sheath on their abdomen for two or three weeks until the egg mass inside is about to hatch into a nymph. In a carefully selected safe and comfortable place, let them come to the world to explore the world alone and travel around the world.
V. Prevention and Control of Indoor Cockroaches Indoor cockroaches breed quickly and in large numbers. They are found in almost every household in the south. People often complain about them and seek a magic bullet to eliminate them. In the long-term struggle against cockroaches, humans have accumulated some effective prevention and control measures, which can be summarized in the following aspects: (1) Eliminate the source of the insect: prevent the spread of cockroaches, especially the ootheca.
(2) Artificial catching. 3. Primary school students have shorter science knowledge
1. Primary school students should learn to swim under the guidance of adults; 2. Do not play alone by rivers or ponds; 3. Do not swim in non-swimming areas; 4. Those who do not know how to swim should not swim into deep water. It is not safe even with a lifebuoy; 5. Make appropriate preparations before swimming to prevent cramps;
2. Self-rescue methods when drowning :
1. Don’t panic, call for help immediately when you find someone around; 2. Relax your whole body, let your body float on the water, raise your head above the water, kick the water with your feet to prevent loss of physical strength, and wait for rescue ; 3. When your body sinks, you can press your palms downward; 4. If you suddenly cramp in the water and cannot reach the shore, seek help immediately. If there is no one around, you can take a deep breath, dive into the water, straighten the cramped leg, and pull the toes up with your hands to relieve the cramp.
3. Rescue methods when someone is found drowning:
Method 1: Throw lifebuoys, bamboo poles, wooden boards and other objects to the drowning person, and then drag him to the shore; < /p>
Method 2: If there is no rescue equipment, you can enter the water and rescue directly. Approach a drowning victim by turning his hips away from you and then hauling. Hauling is usually done by sidestroke or backstroke.
Special emphasis: If minors find someone drowning, they should not rush into the water to rescue. They should shout for help immediately or use life-saving equipment to call for help.
4. First aid for drowning on shore
1. Quickly remove sludge, weeds and secretions from the mouth and nose, keep the respiratory tract open, and pull out the tongue to avoid blockage Respiratory tract; 2. Lift the drowning child so that it lies prone on the rescuer's shoulders, with the abdomen close to the rescuer's shoulders, and the head and feet drooping, so that the water in the respiratory tract can flow out naturally. But do not delay cardiopulmonary resuscitation due to water control; 3. Perform mouth-to-mouth artificial respiration and heart massage; 4. Contact the emergency center as soon as possible or send the drowning child to the hospital. 4. Popular science knowledge famous sayings
Let me answer Einstein: Genius is one percent inspiration and ninety-nine percent perspiration.
Marie Curie’s The weak wait for their opportunity; the strong create their opportunity.
If you can live according to your ideals, act with a spirit of integrity and freedom, courageous perseverance, and honest and non-self-deceiving thoughts, you will surely reach a state of perfection.
We should not waste our lives and should be able to say: "I have done what I can do." On the road to fame, what is shed is not sweat but blood, and their names are not written with pens. It is written with life.
Let us live life happily every day, without waiting until the days are over to find out their loveliness, and without placing all our hopes of special desirability in the future. The basis of science is a healthy body.
I want to turn life into a scientific dream, and then turn the dream into reality. We have to eat, sleep, browse, love, that is, we have to be exposed to the sweetest things in life, but we must not succumb to them.
One must have patience, especially faith. Make life a fantasy, and then turn the fantasy into reality.
The world invisible to human beings is not a fantasy phantom, but a real existence illuminated by the light of science. What is noble is the power of science. 5. Scientific famous phrases
1. The cause of science is to serve the people.
---- Tolstoy 2. Teachers must have a healthy body, the skills of a farmer, a scientific mind, an interest in art, and a spirit of social reform. ---- Tao Xingzhi 3. Scientific books can save people from ignorance, while literary and artistic works can save people from vulgarity; both are equally beneficial and necessary for true education and people's happiness.
---- Chernyshevsky 4. Education! science! To learn to read is to light a torch; every syllable of every word sends out sparks. ---- Hugo 5. Raising a problem is often more important than solving one.
Because solving problems may be just a mathematical or experimental skill, but raising new questions requires creative imagination and marks real progress in science. ---- Einstein 6. Imagination is more important than knowledge, because knowledge is limited, but imagination summarizes everything in the world, promotes progress, and is the source of knowledge evolution.
Strictly speaking, imagination is a real factor in scientific research. ---- Einstein 7. As a scientist, my success... the most important thing is: love of science - infinite patience in long-term thinking about any problem - diligence in observing and collecting facts - Considerable inventive ability and common sense.
---- Darwin 8. For those who engage in science, diligence is the mother of success. ---- Mao Yisheng 9. Without the help of systematic knowledge, innate talents are powerless.
Intuition can solve many things, but not everything. The highest success can be achieved when genius and science are combined.
---- Spencer 10. Science is not something you can get for nothing. It is true that there is no other way to achieve success in science except sweating your face; whether it is enthusiasm or fantasy, you can do it with your whole body and mind. Neither desire nor desire can replace labor. ---- Herzen 11. Intelligent qualifications, inner drive, hard work attitude and perseverance are other conditions required for successful scientific research.
---- Beveridge 12. Successful scientists are often people with a wide range of interests. Their originality may come from their erudition.
Diversity will give people fresh perspectives, while delving into a narrow field for too long can easily make people stupid. ---- Beveridge 13. The most important reason why I can succeed in science is my love for science and my persistence in long-term exploration.
---- Darwin 14. A researcher can live in a back alley, eat rough food, wear rags, and not be recognized by society. But as long as he had time, he could persist in scientific research.
Once deprived of his free time, he is completely ruined and can no longer contribute to knowledge. ---- Cannon 15. Without freedom of thought, there is no science and no truth.
---- Renan 16. Science provides nutrition to the young and comfort to the elderly; it makes a happy life even better, and it protects you in your unfortunate moments.
---- Lomonosov 17. Science can not only "give knowledge to the young and happiness to the old", it can also make people accustomed to labor and the pursuit of truth, and can create real spiritual and material wealth for the people. , can create something that cannot be obtained without it.
---- Mendeleev 18. The sensitivity and originality of youth, once combined with the rich knowledge and experience of mature scientists, can complement each other. ---- Beveridge 19. I think that people have two shoulders, which should play a role at the same time. I want to use one shoulder to carry the burden of door-to-door delivery, and deliver scientific knowledge and scientific tools to the hands of master workers; The other shoulder can be used as a ladder for young people to climb to a higher level of science.
---- Hua Luogeng 20. Self-esteem, fantasy, precocious emotion and sluggish intelligence, coupled with inevitable consequences. Sloth, these are the bane.
Science, labor, practical work. Only then can our sick and dissolute youth wake up.
---- Goncharov 21. If science is unable or unwilling to affect other than its own nation, it is not worthy of being called science. ---- Planck 22. When your throat is dry, you will have the courage to drink even the ocean in one gulp - this is faith; when it comes to drinking, you can only drink two cups at most - this is It's science.
---- Chekhov 23. When you want to drink water, you feel as if you can drink the entire ocean - this is faith; when you really drink it, you can only drink two ounces in one cup. Just a cup - this is science. ---- Chekhov 24. For those who engage in science, diligence is the mother of success! ---- Mao Yisheng 25. Science has no national boundaries, because it is a wealth that belongs to all mankind and a torch that illuminates the world, but scientists belong to the country.
Pasteur 26. Science has no national boundaries, but scientists have national boundaries. ---- Pavlov 27. Although science has no borders, scholars have their own country.
---- Pasteur 28. To learn knowledge, you must be good at thinking, thinking, and thinking again. This is how I became a scientist. ---- Einstein 29. If learning only consisted in imitation, then we would have no science and no technology.
---- Gorky 30. To build, you must have knowledge and master science. To have knowledge, you must study, study tenaciously and patiently.
Learn from everyone, whether from enemies or friends, especially from enemies. ---- Stalin 31. Socialism is a scientific and cultural society.
To become a well-deserved member of the socialist society, you should study hard and well and acquire a lot of knowledge. ---- Kalinin 32. On the road of science, there is no smooth road. Only those who work hard on the rugged path can reach the glorious peak.
---- Marx. 6. Famous quotes about popular science knowledge
I can only say that this is a great work! Carl Sagan made significant and far-reaching contributions to many aspects of science and society, and influenced hundreds of millions of people around the world.
His important research in the field of planetary science is closely related to the U.S. space program. Carl Sagan was a great astronomer, extraterrestrial life scientist, and a great science popularizer, winner of the Pulitzer Prize.
He is the author of many best-selling popular science books, including Carl Sagan's Universe, a fascinating and beautifully illustrated collection of essays by multiple authors covering Sagan's work as a He devotes himself to science, education, policy development and many related fields. The film is part of his highly acclaimed television series of the same name.
Chapter 1 The Frontier of the Universe Humanity’s exploration of the universe is very exciting in retrospect. These exploratory activities remind us that curiosity is a human habit, understanding is a pleasure, and knowledge is a prerequisite for survival.
Because we are just a speck of dust flying in the morning sky in this universe, we believe that the future of mankind depends on how well we understand this universe. ... Chapter 2 The Music of the Universe Before the birth of life, the earth was once a barren and barren land.
Today, our planet is teeming with life. Why does this happen? How did organic molecules with carbon as the core form in the absence of life? How did the first living things come about? How did living things evolve to reproduce complex, advanced animals like us that are capable of exploring their own mysteries? ... Chapter 3 Harmony of the Universe If we lived on an unpredictable planet, we would not be able to understand things, and there would be no such thing as science.
Things here are changing, and their changes follow certain patterns, rules, or so-called natural laws. If we throw a bamboo pole into the air, the bamboo pole will always fall.
If the sun sets in the west, it always rises in the east the next morning. So it's possible for us to understand things, we can do scientific research, and use science to improve our lives.
… Chapter 4 Heaven and Hell The universe has been destroyed before, and we humans are even known for being “good at inflicting disasters on ourselves intentionally or unintentionally.” Other planets have preserved their past histories, and there is ample evidence that they have experienced cataclysms.
Everything is just a matter of time. What is unthinkable in 100 years may be inevitable in 100 million years.
… Chapter 5 The Mysterious Red Planet The power of Lowell’s idea may lie in making it a prophecy. It was he who believed that the Martians built the canal network.
Even this view may become a definite prediction: If Mars is to be transformed, it will be completed by humans. Mars is another planet that humans can permanently live on. The Martians will be us humans.
... Chapter 6 The Voyager's Story On July 9, 1979, the "Voyager 2" spacecraft arrived at the Jupiter galaxy after almost two years of interplanetary navigation. The spacecraft is made up of millions of subassembly parts, each with a spare part, so if one part fails, other parts will take over its function.
The spacecraft weighs 0.9 tons and requires a large house to accommodate it. ...Chapter 7 The Spine of the Night Sky The Khun Bushmen in the Kalahari Desert of Botswana have a unique way of talking about the Milky Way.
They are in an area where the Milky Way is often right above their heads. Therefore, they call the Milky Way "the spine of the night sky", as if the sky is some kind of giant beast, and people live in the belly of the giant beast.
… Chapter 8 Traveling in Time and Space The beach reminds us of the universe. The fine sand grains on the beach are basically uniform in size. They are formed by the impact and friction, corrosion and weathering of large rocks by waves over many years, and all of this is driven by the distant moon and sun. happened.
The beach also reminds us of time, and that the earth itself is much older than humans. ... Chapter 9 The Life of Stars The Milky Way is still an unexplored world full of magical stars.
Although we have conducted preliminary exploration of the Milky Way and are encountering some of its stars, some are similar to the stars we know, and some are weird beyond our imagination. ,... Chapter 10 The End of Forever 10 or 20 billion years ago, something extraordinary happened - the Big Bang, which exploded our universe. Why the Big Bang happened is the biggest mystery to us.
...... Chapter 11 Letter to the Future We hope that in the not too distant future, in the foreseeable cosmic era, we will complete a great cause, that is, to peacefully unify our planets into one cherished planet. The institutions of every living thing on our celestial body, and then calmly take the next great step, turning the planet Earth into a part of the galactic society that can be interconnected with all civilizations. ...Chapter 12 Encyclopedia of the Galaxy One day, on a planet in a distant star, a life that is very different from each of us may ask us to send them the latest version of the Encyclopedia of the Galaxy "Complete Book" to obtain some information about this latest society that has just joined the Milky Way's collective body of civilizations.
Chapter 13 Appeal for the Earth Because we are the incarnation of a part of the universe that has developed self-awareness, we have begun to consider our origins.
We are thinking deeply about the planetary material of other planets, which is a collection of 1028 atoms. We are exploring the evolution of atoms and tracking the long process of the emergence of consciousness.
We should be loyal to all mankind and to the entire earth. It’s up to us to speak up for the planet.
To maintain human survival is not only responsible for ourselves, but also responsible for the universe, this ancient, vast universe that gave birth to us. Category: Science and Education.