Common sense: Science around us: Why do you see lightning first and then hear thunder? Because light waves travel faster in air than sound speed.
Science around us: Why can't we 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 decline. Science around us: Why should we install a black box on the plane? A: It is used to record various situations on the plane during the crash and help people understand the cause of the accident.
Science around us: Why does the bicycle move? Bicycle tires rub against the ground. Science around us: Why does it make a "swish" sound when it is windy? When a strong wind touches something as slender as wires or branches, it will make a "swish" sound.
The slender whip shakes violently in the air, and a vortex of air is formed behind the whip, which makes the air vibrate and make a sound. The way the wind blows branches is like waving a whip.
When the wind blows at an acute angle or behind the gap, it will also form this vortex and make a "swish" sound, and the tone will be different according to the strength of the wind. Science around us: How do bees make honey? First, the bees spit the sweet juice of the flowers they picked into an empty hive. At night, they suck sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 100~240 times to make sweet honey.
2. 50 little scientific knowledge around you
Science around you As long as you pay attention, science is everywhere.
On Saturday, the teacher assigned an assignment to do a scientific experiment. I thought about it and finally came up with an experiment. I want to do a scientific experiment that eggs will float.
Prepare a cup, an egg and some salt. Put water, eggs and salt in the cup first.
It's strange that the egg didn't float at this time. As soon as I thought about it, I added salt to the cup in spoonfuls.
After adding a few spoonfuls, I found that the eggs began to float slowly. Gradually, the eggs rose to the surface like an elevator.
Why do eggs float from salt water? Because after adding salt to the water, the density of salt water becomes larger, and the buoyancy is greater when the density is larger, and the eggs can be held up when the buoyancy is greater. This scientific experiment is really interesting. I'll try again.
Chapter 2: Science around me One night, my mother bought a bag of metapenaeus ensis. The base-tailed shrimp is blue, but the cooked base-tailed shrimp turns red. I asked my mother. My mother didn't tell me the answer directly, but gave me a book, Question and Answer, to find the answer by myself. I looked for it and finally found it, because there is a pigment called astaxanthin in shrimp. Usually mixed with other pigments, it can't show its bright red color, but after heating, all other pigments are destroyed and decomposed, except astaxanthin, which is not afraid of high temperature, so shrimp turns red after cooking.
It turns out that there is science everywhere in life! Chapter 3: Science around us Speaking of science, in fact, many things happening around us are solved by science. Let me give you a simple example.
I remember once, my mother asked me to open the vinegar bottle when I was cooking, but I just couldn't unscrew it. Later, my mother told me that it was easy to unscrew the vinegar bottle by soaking it in hot water for five minutes and then washing it with cold water.
In this way, I tried to do it in my mother's way. Sure enough, the vinegar bottle was easily unscrewed.
My mother told me that this is the effect of heat expansion and cold contraction. After this incident, I sincerely thank science, which makes me progress and helps me grow.
3. 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
There is little scientific knowledge around us.
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.
How do bees make honey? First, the bees spit the sweet juice of the flowers they picked into an empty hive. At night, they suck sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 100~240 times to make sweet honey.
How do birds sleep? During the day, birds shuttle in the branches, chirp and fly freely under the blue sky. At night, they should rest, sleep and recover their strength like us, but the sleeping posture is different! Beautiful mallard ducks and swans hunt and play in the water during the day, but they can't rest when they leave their favorite water at night. They bend their beautiful long necks, bury their heads in their wings, and then let themselves float on the water, dreaming a beautiful dream, drifting with the tide, very leisurely. Long-legged birds such as cranes, storks and herons always sleep independently on one foot, and when they are tired, they change their other feet, which is a model of combining work and rest. Partridges like to form a big circle in groups when resting, and then their heads are outward and their tails are inward. In this way, no matter which direction the enemy attacks, they can find and escape in time. Birds with sweet voices, such as blackbirds and larks, usually bend their legs when sleeping, and their claws bend to firmly grasp the branches without worrying about falling from the trees. And the owl, a "night-shift" raptor, you can always see it standing on a dense branch with one eye open during the day, actually sleeping. Isn't the owl's sleeping position very different? Is to monitor the surrounding environment at all times and guard against enemy attacks.
5. What little scientific knowledge do the pupils around you have?
1. 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.
2. 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.
3. Why can snakes walk without feet?
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!
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 the sunflower immediately hides to the side of the backlight, as if the whole plant is bent in the direction of the sun.
5. Why does hair turn white when people are old?
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!
6. Why do fireflies glow?
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.
The purpose of fireflies is not only lighting, but also courtship, vigilance and trapping. 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 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 be stirred up and purr.
Don't be embarrassed by your stomach growling next time! Because this is a normal physiological action.
8. Why 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.
Ostriches live in Africa. Because they have lived in desert areas for a long time, their bodies gradually evolved into what they are now in order to adapt to the environment.
9. Why can't it go bad easily?
Lunch meat, black bean shad, 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, so bacteria can't enter.
When people make canned food, they pump all the air out of the canned food and then seal it. In the absence of air, even if the food inside is contaminated with a little bacteria, they can't survive or reproduce!
10. Why does the baby cry all the time when it is 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.
1 1. Why do lizards keep bouncing up after their tails are broken?
In order to protect themselves, many lizards also protect their eyes and ears; When some lizards are attacked, their tails will be broken due to the severe contraction of their muscles. Because there are still some nerves alive in the broken tail, it will keep bouncing, thus distracting the enemy and running away. Don't think that their lives will end like this. In fact, it only takes a few months, and their tails will grow back and move on.
What is your little scientific knowledge about 6.50?
1. Why does a lizard bounce backwards when its tail is broken?
In order to protect themselves, many lizards also protect their eyes and ears; When some lizards are attacked, their tails will be broken due to the severe contraction of their muscles. Because there are still some nerves alive in the broken tail, it will keep bouncing, thus distracting the enemy and running away. Don't think that their lives will end like this. In fact, it only takes a few months, and their tails will grow back and move on.
2. Why is the squirrel's tail so big?
Don't look at the relaxed mouse tail! When the squirrel jumps around the tree, its tail plays a great role. It can keep balance when the squirrel jumps to the tree to avoid falling and being injured. In addition, this big tail can play a more protective role in winter, tightly surrounding the squirrel's body, which is convenient and practical.
3. Why can't a person's thumb have one or three knots?
The average person has five fingers, each with a different length. However, does anyone realize that besides the thumb, other fingers also have three sections, while the thumb alone has only two sections? It turns out that the number of joints is just the same as the other four fingers. If it is three knots, the thumb will appear weak, so that it can't lift heavy objects; If there is only one section, it can't grasp things freely with the other four fingers!
4. Why don't you scratch yourself?
When others scratch ourselves, we will feel itchy and laugh constantly; 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!
5. Why is the sea mostly blue and green?
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.
6. Why can a snake walk without feet?
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!
7. 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 the sunflower immediately hides to the side of the backlight, as if the whole plant is bent in the direction of the sun.
8. Why does hair turn white when people are old?
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!
9. Why do fireflies glow?
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. The purpose of fireflies is not only lighting, but also courtship, vigilance and trapping. 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.
10. Why 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 be stirred up and purr.
7. Little scientific knowledge around you
You should eat bread before drinking milk.
Milk is a kind of natural food with the most comprehensive nutrition, the most appropriate proportion and the easiest digestion and absorption by people. But drinking milk is very particular.
If the method is improper, the effect will be greatly reduced. Experts believe that drinking milk is the best.
No sugar. Otherwise, it will not only be difficult to be digested and absorbed, but also stay in the digestive tract, affecting gastrointestinal function. Milk can be heated, but not boiled. because
After boiling, some vitamins will be destroyed, and calcium in milk will form calcium phosphate precipitation, which is not easily absorbed by the human body. Don't just drink milk for breakfast. Drinking milk on an empty stomach will accelerate gastrointestinal peristalsis and cause malabsorption. The correct way is to eat bread, cakes, etc. First, then drink milk, which will make the nutrition more balanced. At the same time, don't eat chocolate while drinking milk. Because oxalic acid in chocolate will combine with calcium in milk to form calcium oxalate, calcium can not be fully absorbed by human body.
Why does milk have a layer of skin after heating?
The skin floating on the surface of milk is solidified, protein. Milk contains all the nutrients necessary for the growth and development of cattle, and protein is one of the most important nutrients. Once heated, protein will solidify. Cooked eggs will solidify, because the protein in the eggs will solidify. Protein in milk will also be solidified by heating. Protein, especially protein in milk, will solidify when it goes bad even if it is not heated. Protein spoilage will produce acid, which can solidify milk. Although yogurt solidified with lactic acid bacteria can be eaten, it is best not to eat naturally deteriorated and solidified milk, because we don't know what kind of bacteria it will contain, which will make people sick.
8. Second-grade Chinese Garden Book 2 Oral Communication 8 Scientific knowledge around us.
The simplest, gear design, keyboard design, and coding, these are very classic, the number of gears is prime, in order not to break it, whoever uses it is out of his mind, keyboard, probability! Electric lights, telephones, automobiles, watches, clothing, shoes and hats, and scientific knowledge related to electricity, electronics, machinery, materials and chemical industry. When an athlete is injured, spray alcohol on the wound (internal injury).
Sprinkle water on the door to cool down.
There is a pond under the rocket launcher for the high heat generated by rocket fuel.
People look in the mirror every day by using the reflection phenomenon of light (flat mirror imaging)
Roasted sweet potatoes use heat (radiation).
Holding the bottle in your hand without tipping it is the use of friction.
Ships use sonar to locate the seabed through the reflection of sound.
Incandescent lamps use the thermal effect of electric current to emit light.
Look in the mirror, periscope, car rearview mirror, light pollution, reflection (light reflection)
Earthphone made of cups, fish in the water can be scared away by people's voices and footsteps on the shore, radar locator, echo, drum vibration when drumming, ears in the wall, noise (sound phenomenon)
Solar eclipse, lunar eclipse, building height measurement or flagpole height measurement, pinhole imaging, eye alignment of woodworking planer, shadow and light beam (linear propagation of light) emitted by film projector to the screen.