Popular science knowledge card 1.50 scientific knowledge
Why do sunflowers always face the sun? Sunflower stems contain a wonderful auxin.
This auxin is very afraid of light. When it is illuminated, it will go to the backlight side, and the cells on the backlight side will multiply rapidly. Therefore, the backlit side will grow faster than the bright side, which will bend the sunflower to light.
2. Why do the stars twinkle? We see the stars shining, not because the luminosity of the stars has changed, but because of the occlusion of the atmosphere. The atmosphere is between us and the stars. When starlight passes through the atmosphere, it will be affected by the density and thickness of the atmosphere.
The atmosphere is not absolutely transparent, and its transparency will change according to its density. So when we look at the stars through it on the ground, we will see that the stars seem to be flashing.
3. 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.
How high is the blue sky? "Blue sky" is actually the earth's atmosphere. The atmosphere surrounds the earth's air and is divided into five layers according to the air density, with a total thickness of 2000-3000 kilometers.
But most of the air is concentrated below 15 km from the ground, and the higher the air, the thinner it is. How thick the atmosphere is, how high the blue sky should be.
5. Why are there no stars in the daytime? Because part of the sunlight is scattered by the gas and dust in the atmosphere during the day, the sky is very bright and the light radiated by the sun is so strong that we can't see the stars. 6. What celestial bodies are there in the solar system? There are nine planets in the solar system.
They are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. In addition, there are many asteroids, comets and meteors in the solar system, and there are 2958 officially numbered asteroids.
The most famous comet is Halley's comet. 7. Why does it thunder? This is a natural phenomenon that negative electricity meets positive electricity.
When it rains, some clouds in the sky are positively charged and some are negatively charged. When two clouds meet, they will discharge, emit bright and bright lightning, and at the same time release a lot of heat, which will make the surrounding air heated, expand and make a loud noise. This is thunder. 8. Why can an airplane fly into the sky? This plane has two wings, like those of a bird. It has a propeller.
The wing can generate lift and lift the plane into the air; Propeller can produce the ability to push the plane forward. Therefore, the plane can fly into the sky like a bird.
33. For a quartz clock hanging on the wall, when the battery runs out and stops, its second hand often stops at the position of "9" on the dial. This is because the second hand is most hindered by the large torque at the "9" position.
9. Before water boils, bubbles in water rise and vibrate up and down due to convection. Most bubbles burst under the pressure of water, and their bursting sound and vibration sound are very loud with the container. After water boils, it is isothermal up and down, and the bubble volume increases. Under the action of buoyancy, it will burst as soon as it reaches the water surface, so the noise is relatively small.
10. Fire-water incompatible substances must reach the ignition point when burning. Because of the large specific heat of water, water can absorb a lot of heat when it comes into contact with fire, thus reducing the temperature of ignition materials; At the same time, the vaporized water vapor surrounds the burning object, making it impossible for the object to contact with air. Without air, combustion cannot be carried out. 1 1. Sit on the ground and walk for 80,000 days. Because the radius of the earth is 6370 kilometers, every time the earth makes a circle, the distance that objects on its surface "walk" is about 40003.6 kilometers, about 80000 miles.
This is a poem sung by * *, which also scientifically reveals the relationship between motion and stillness-motion is absolute, and stillness is always relative to the reference object. 12. According to the principle of lever balance, if the power arm is a fraction of the resistance arm, then the power is several times the resistance.
If the weight of the arm is very large, it is entirely possible to "dial one or two kilograms." 13. When the distance between molecules is large (more than several hundred angstroms), the attraction between molecules is very small, almost zero, so it is difficult to reassemble a broken mirror.
14. If the directions of the components are the same, the resultant force is equal to the sum of the components. 15. Tofu can't be hung with hemp rope. When the pressure is constant, if the stress area is small, the pressure will be great.
16. True gold is not afraid of fire, and truth is not afraid of argument. Judging from the melting point of gold, although it is not the highest, it is 1068℃, while the temperature of general flame is about 800℃. Because the temperature of the flame is lower than the melting point of gold, gold cannot be melted. 17. With a long whistle, people in the valley should give a long whistle. After many reflections, the sound can form a loud echo for a long time. As if the mountains were shouting and the valleys were echoing.
18. Looking at the sky from the well, you can see very little. Because light travels along a straight line, from the knowledge of geometric drawing, the frog's field of vision will be very small. 19. It can be seen from the pressure formula that when the pressure is constant, the smaller the stress area, the greater the pressure.
People will feel very uncomfortable sitting on such a blanket. 20. Good years are bright. Because snow is a bad conductor of heat, when it covers crops, it can well prevent heat conduction and air convection, so it can play a role in heat preservation.
2 1. It is cold before frost and cold after snow. In the late autumn night, the temperature near the ground suddenly turns cold (the temperature is below 0℃), and the water vapor in the air condenses into small ice crystals and adheres to the ground to form frost, so it feels "cold before frost". When snow melts, it needs to absorb heat to reduce the temperature of the air, so we have the feeling of "cold after snow".
22. Eggs touch stones-overreached eggs touch stones. Although the force is the same, the pressure that each object can bear is certain. If this limit is exceeded, the object may be damaged. Eggs can withstand less pressure, so they will break.
23. Before the jade is polished, the surface is uneven and the light is diffuse. After the jade is polished, the surface is smooth and the light is mirrored. 24. Fans have a cool breeze, which is suitable for summer but not for winter.
2. About 20 words of scientific and technological knowledge.
3. Why can snakes walk without feet? Can a snake walk without feet? A snake has many scales on its body, which is the outermost layer of armor. Scales are not only used to protect their bodies, but also can be their "feet". When a snake crawls forward, its body will be S-shaped. Every scale except the S-shape will be tilted to help the snake grasp the uneven road when it moves forward. These scales cooperate with the muscles of snakes and can push their bodies to crawl forward, so snakes can walk without feet! 4. Why do sunflowers always bloom towards the sun? There is a substance called "auxin" in the stem under the sunflower disk. This substance has the function of accelerating replication, but it is anti-optical, and it will run to the backlight side whenever it encounters light. So when the sun rises, the stem of sunflower will immediately hide to the side of the backlight, and it seems that the whole plant is bent towards the sun. 5. Why do people get old? When people get old, their hair will turn white. There is a substance called melanin in our hair. The more melanin, the darker the 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! 6. Why do fireflies glow? Can fireflies shine? Fireflies emit light because there is a luminous body at the end of their abdomen, which is filled with a lot of phosphorus-containing luminescent substances and luminescent enzymes, so that fireflies can emit flashing light. Fireflies shine not only for lighting, but also for courtship, vigilance, trapping and other purposes. This is also a communication tool for them. Different kinds of fireflies emit light in different ways, frequencies and colors, so they can convey different information. 7. Why are they hungry? 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 stir up and make a purring sound. Don't be embarrassed by the growling of your stomach next time! Because this is a normal physiological action. 8. Why can't ostriches fly? Can't ostriches fly? A giant ostrich, but they can't fly into the sky! This is not because their wings are useless, but because their feathers are too soft and their wings are too small to fly at all. In addition, the ostrich's muscles are underdeveloped and its sternum is flat, which is not conducive to flying. Ostrich has lived in Africa for a long time, and in order to adapt to the environment, its body has gradually evolved into what it is now. 9. Why can't the food in cans go bad easily? Isn't the food in cans easy to go bad? Lunch meat, black beans, tomato sauce beans.
They are all delicious canned food, which can be preserved for a long time without deterioration. This is because the can is sealed and bacteria can't get in. When people make canned food, they pump out all the air inside and seal it. Without air, even if the food inside is stained with a little bacteria, they can't survive or reproduce! 10. Why do babies always cry at birth? Do babies always cry when they are 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.
About 3.20 words of scientific knowledge. Thank you.
Small scientific knowledge
Why does sorbet get angry?
The reason why sorbet bubbles is because there is a lot of invisible water vapor in the outside air. When it comes to cold sorbet, it will liquefy into droplets when it is cold. It seems that the sorbet is bubbling.
Why do sunflowers always face the sun?
Sunflower stems contain a wonderful auxin. This auxin is very afraid of light. When it is illuminated, it will go to the backlight side, and the cells on the backlight side will multiply rapidly. Therefore, the backlit side will grow faster than the bright side, which will bend the sunflower to light.
Why does cicada shed its skin?
Cicada's shell (exoskeleton) is hard and can't expand with the growth of cicada. When the cicada grows to a certain stage, the cicada's exoskeleton restricts its growth, and the cicada loses its original exoskeleton, which is cicada slough.
4. Primary school students' popular science handwritten newspaper content
The reason why sorbet bubbles is because there is a lot of invisible water vapor in the outside air. When it comes to cold sorbet, it will liquefy into droplets when it is cold. It seems that the sorbet is bubbling.
Sunflower stems contain a wonderful auxin. This auxin is very afraid of light.
When it is irradiated by light, it will go to the backlight side, and at the same time, the cells on its wide side will multiply rapidly, so the backlight side will grow faster than the light side, which makes the sunflower bend to the optical rotation. Cicada's shell (exoskeleton) is hard and can't expand with the growth of cicada. When the cicada grows to a certain stage, the cicada's exoskeleton restricts its growth, and the cicada loses its original exoskeleton, which is cicada slough.
Bees first spit the sweet juice of the collected flowers into an empty hive. At night, they suck the sweet juice into their honey stomachs for modulation, and then spit it out and swallow it. This takes 100~240 times, and finally it becomes sweet. We see the stars shining, not because the luminosity of the stars has changed, but because of the occlusion of the atmosphere. The atmosphere is between us and the stars. When starlight passes through the atmosphere, it will be affected by the density and thickness of the atmosphere.
The atmosphere is not absolutely transparent, and its transparency will change according to its density. So when we look at the stars through it on the ground, we will see that the stars seem to be flashing.
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.
Snakes have many scales, which are the outermost armor on their bodies. Scales are not only used to protect the body, but also to be their "feet".
When a snake crawls forward, its body will be S-shaped. Every scale outside the S-shape will tilt upward to help the snake catch the uneven road when it moves forward.
These scales cooperate with the snake's muscles and can push the body forward, so the snake can walk without feet! 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. 10 when others scratch ourselves, we will 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 a message that there is no danger, and the nerves will relax, so that they will not laugh and itch! 1 1 Looking at the sea, it is often found that the sea water is blue-green.
However, when you pick up the sea water, you can only see it as transparent and colorless as old water. It turns out that the seawater itself is not much different from the water we touch every day, and it is also transparent.
The green we see is actually a phenomenon caused by the ability of seawater to absorb light. Only green light can be absorbed and reflected by seawater; When the seawater is deep, the green light is also absorbed, and the seawater looks blue.
12 There are hairs on the surface of our skin, and there is a vertical hair muscle under each pore. When we come into contact with nerves (such as anger, fear, cold, etc. ), our body temperature will drop, the vertical hair muscles will contract, which will make 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.
5. 50 little scientific knowledge around you
Science is everywhere. Here are 50 scientific tips 1.
Why do you see lightning first and then hear thunder? Light waves travel faster in air than sound speed by 2. Who was the first Olympic champion in China? Xu Haifeng III.
Who invented glasses? Roger? Bacon 4. Why does the bicycle move? Bicycle tires rub against the ground.
Whose title is the following? Poet Fairy-Li Bai, Poet Saint-Du Fu,-Li He, Poet Bone-Chen Ziang, Poet Crazy-He 6. What does the moon revolve around? How long does it take to make a revolution? Earth, 27.32 days 7.
What are the three plains in China? Northeast Plain, North China Plain, Middle and Lower Reaches of the Yangtze River Plain. How many earthquakes are there on the earth every year? About 5 million times.
What is the smallest and coldest star in the solar system? Pluto 10. What is the thickness of the earth? Atmosphere 1 1.
Why are there black boxes on the plane? It is used to record all kinds of situations on the plane during the crash and help people understand the cause of the accident. What are the customs during the Spring Festival? Sweep the house, set off firecrackers, put up Spring Festival couplets, eat New Year's Eve, etc. 13.
What animal can predict earthquakes? Cattle, horses, rabbits, chickens, ducks, dogs, snakes, rats, fish, etc. What plant blooms first and leaves later? Chimonanthus praecox, kapok, forsythia suspensa, peach tree, winter jasmine, pear tree, silver willow, bauhinia, Xiang Jie, Lycoris radiata and plum blossom 15.
How do bees make hives? Every worker bee has a wax gland at the waist, which can secrete wax. This wax becomes soft and tough after chewing in the mouth, and can be used to build a honeycomb. Why is the medicine bottle so light? Because light color can reflect light, dark color absorbs more light when exposed to sunlight, so drugs are easy to deteriorate.
Who invented the steam engine? Watt 18. Which dinosaur is the hardest? Stegosaurus 19.
What is the blood of the earth? Magma 20. What is the skeleton of the earth? Rock 2 1
Why not watch welding sparks? It contains ultraviolet rays harmful to the eyes. Why can't you turn off the lights and watch TV? The screen and image of TV are relatively small. In the dark, the vision should be highly concentrated and expanded, and it is particularly sensitive to the strong reflection of light on the TV screen, which will make the eyes suffer from * * * and the vision will drop by 23%.
Who are the top ten marshals of China people? Zhu De, Peng, He Long, Chen Yi, Liu Bocheng, Luo Ronghuan, Xu, Nie, Lin Biao, ** 24. Write down the dynasties in ancient China in order. Xia, Shang, Zhou, Qin, Han, Sui, Tang, Song, Yuan, Ming and Qing 25.
Why don't rabbits need water? Because the rabbit's staple food vegetables contain a lot of water, which is enough for the body. If there is more water in the intestine, you will get gastroenteritis. But rabbits can drink water when they are short of water.
What is a meteor? It refers to meteoroids running in interstellar space (usually including cosmic dust particles and solid blocks), which are attracted by the earth due to the perturbation of the earth's gravity when approaching the earth, and then enter the earth's atmosphere and burn with it. List some outstanding astronomers in the history of China.
Zhang Heng and his party, Guo Shoujing and Li, 28 people. Who is the inventor of the battery? Volt 29.
Where is Mount Vesuvius? Italy. 1 who are the two astronauts who arrived at the moon? Armstrong and Aldrin 3 1.
Which province and city is Mount Tai in? Taishan City, Shandong Province 32. Which countries does the Amazon River flow through? Brazil, Peru and Colombia.
Which countries does the Irrawaddy River flow through? China, Myanmar. What are the five most precious gems in the world? Diamonds, sapphires, rubies, emeralds and opals.
What was the name of the ancestor of the fish? Amphioxus 37 What kind of fish glows? Ankang fish, snapper, dragon head fish, naked eye fish, etc.
How many muscles does a person have? A * * * has more than 600 muscles. Will all the wood float on the water? No, there is a kind of "steel tree" that won't float on the water.
What is the biggest flower? Dawanghua 4 1. Who invented anesthesia? Hua tuo 42.
What is the capital of France? Paris 43. What is the capital of England? London 44.
What is the capital of Japan? Tokyo 45. What is the capital of Italy? Rome 46.
What is the capital of the United States? 47 Washington. What bird is one of the ancestors of birds? Archaeopteryx 48.
What are the four seafood products in China? Pseudosciaena crocea, Pseudosciaena crocea, hairtail, squid. What is the largest mammal? Blue whale 50.
What is the largest amphibian? giant salamander
6. Seek 15 scientific knowledge
1. According to Xinhua News Agency, Institute of Computing Technology, Chinese Academy of Sciences has successfully developed the first high-performance general-purpose microprocessor chip in China? Godson12. Which Olympic Games is the 2008 Beijing Olympic Games? The 29th Olympic Games.
3. At present, where is China's comprehensive national strength in the world? Sixth place. 4. Guo Moruo: "The world is scarred, and the sage in the poem; The people suffer, and the bottom of the pen fluctuates. "
Who is the compliment? Like Du Fu. 5. "The sound of reading in the wind and rain is in the ear; Family affairs and state affairs, everything cares. "
Which ancient academy inscribed it? Inscription of Donglin Academy. 6. "People who protect the world are ashamed of their husbands and have the responsibility."
(In the Ming Dynasty, Gu's Record of the Day, Volume XIII, Official History) Which sentence was this sentence extended to by later generations? "Every man is responsible for the rise and fall of the world." 7. What is the river of life in Taklimakan Desert, the largest desert in China? Tarim river.
8. Which nationality is the Songkran Festival? An important festival of the Dai people. 9. What is the largest bronze ware found in the world so far? Smoothing 19. What is China's earliest collection of poems? The book of songs 1 1, which is known as "a historian's swan song, Li Sao has no rhyme", is a historical masterpiece? "Historical Records" 12, after Qin unified the six countries, what money did the whole country use? Round square hole money
13. What was the largest series of books compiled in China and even the world during the Qianlong period of the Qing Dynasty? Siku quanshu 14. What is the largest nature reserve in China? Sanjiangyuan Nature Reserve (Yangtze River, Yellow River and Lancang River) 15. Who was the first thinker in the world who put forward the population theory during the Warring States Period in China? (Han Fei).
7. Popular science knowledge handwritten newspaper content
The charm of science is everywhere. As long as we take the initiative to explore with curiosity, we will find many interesting phenomena in life, such as the following 10 knowledge, which will definitely make your posture soar.
1. The largest monkey in the world is a baboon, and the smallest monkey is a bonobo. Baboon 2. By yawning and deep breathing, the human body increases the oxygen in the blood and discharges more carbon dioxide, thus making people more energetic.
When people are sleepy, they often yawn constantly to remind people that their brains are tired and need sleep and rest. People can drink about 80 tons of water in their lifetime.
Note: If a person lives to 60 years old, he will drink about 43,500 kilograms of water in his life, that is, if he drinks 2 liters (kilograms) of water every day, 60*365 days *2 kilograms = 43,800 kilograms, minus about 300 kilograms in infancy. Needless to say, you have to drink 80 tons of water to live to 60 years old. 4. The brightest star in the sky is Sirius Canis, with a magnitude of-1.46 and a distance of 8.7 light years from the Earth. Everyone must have the habit of picking their noses.
According to the survey, 90% people put their fingers into their nostrils several times a day. According to research, picking your nostrils may introduce dangerous bacteria into your nostrils, such as Staphylococcus aureus.
6. Morning glow and sunset glow are the most beautiful colors in the sky. It is formed because sunlight passes through the thick atmosphere around sunrise and sunset and is scattered by a large number of air molecules.
7. There is always lightning in Lake Maracaibo in Venezuela. Even scientists don't know why, but it seems that lightning is caused by airflow combined with local topography. There used to be giant dragonflies in ancient times.
The giant vein dragonfly appeared about 300 million years ago, about as big as a seagull, and its wings are about 65 cm long. 9. Lobsters die from molting, being eaten or being injured. They can live to be 70 without getting old first. If these three things don't happen, we can continue to live forever.
10, "White rabbit, white, so cute to jump". Rabbits beat the ground with their legs to transmit information, mostly with their hind legs, which is a way for them to express their feelings to female rabbits.
8. Encyclopedia of scientific knowledge (30 words)
Scientific common sense in life:
1. Why does sorbet get angry?
The reason why sorbet bubbles is because there is a lot of invisible water vapor in the outside air. When it comes to cold sorbet, it will liquefy into droplets when it is cold. It seems that the sorbet is bubbling.
2. Why do sunflowers always face the sun?
Sunflower stems contain a wonderful auxin. This auxin is very afraid of light. When it is illuminated, it will go to the backlight side, and the cells on the backlight side will multiply rapidly. Therefore, the backlit side will grow faster than the bright side, which will bend the sunflower to light.
3. Why do cicadas shed their skin?
Cicada's shell (exoskeleton) is hard and can't expand with the growth of cicada. When the cicada grows to a certain stage, the cicada's exoskeleton restricts its growth, and the cicada loses its original exoskeleton, which is cicada slough.
4. How do bees make honey?
Bees spit the collected sweet flower juice into an empty beehive. At night, they suck sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 65,438+000 ~ 240 times to make sweet honey.
5, hanging on the wall of the quartz clock, when the battery runs out and stops, its second hand often stops at the "9" position on the dial. This is because the second hand is most hindered by the large torque at the "9" position. Scientific common sense
6. Sometimes, when tap water flows from the adjacent faucet, it occasionally makes bursts of noise. This is because the water pipe vibrates when the water rushes out of the tap.
7. When taking pictures on TV, turn off the camera flash and indoor lighting to make the picture clearer. Because the reflected light of the flash lamp and the illuminating lamp on the TV screen will interfere with the transmitted light of the TV picture.
8. At the same temperature, frozen meat thaws faster in water than in air. At the same temperature, hot nails cool faster in water than in air. A cup filled with boiling water cools faster when immersed in water than when immersed in air at the same temperature. All these phenomena show that water has better heat transfer performance than air,
9. When there is cold water in the pot, the water droplets attached to the outer surface of the pot bottom can only be dried up after a long time on the flame, and will only boil when it is dried up. This is because the water droplets, the pot and the water in the pot keep heat conduction, and the temperature is almost the same. As long as the water in the pot is not boiled, the water droplets will not boil, and the water droplets will evaporate on the flame and be gradually dried up.
10, out-of-shape mirror, the farther away from the mirror, the more out of shape. Because the image in the mirror is formed by the reflection of the silver-plated surface behind the mirror, uneven silver-plated surface or uneven glass thickness will lead to aliasing. The farther away from the deformed mirror, the more the reflected light on the silver-plated surface deviates from the normal position according to the principle of light amplification, and the more deformed the mirror is.
About 9.20 words of scientific knowledge. Thank you.
Why does scientific sorbet get angry? The reason why sorbet bubbles is because there is a lot of invisible water vapor in the outside air. When encountering a very cold straight sorbet, it will liquefy into droplets and surround the sorbet when it gets cold. It seems that the sorbet is bubbling.
Why do sunflowers always face the sun? Sunflower stems contain a wonderful auxin. This auxin is very afraid of light.
When exposed to light, it will go to the backlight side, and the cells on the backlight side will multiply rapidly, so the backlight side will grow faster than the light side, which will bend the sunflower to the light side. Why does cicada shed its skin? Cicada's shell (exoskeleton) is hard and can't expand with the growth of cicada. When the cicada grows to a certain stage, the cicada's exoskeleton restricts its growth, and the cicada loses its original exoskeleton, which is cicada slough.