1. The strongest muscle in the human body is the tongue.
It is impossible to sneeze with your eyes open.
It is impossible to hold your breath and commit suicide.
Every time you lick the stamp gum, it is equivalent to absorbing110 heat.
Right-handed people live nine years longer than left-handed people on average.
Crocodiles cannot stick out their tongues.
7. Polar bears are left-handed.
8. An ostrich's eyes are bigger than its head; Starfish haven't evolved their heads yet.
9. A flea can jump 350 times its own length, which is equivalent to a person jumping over an American football field.
10. A cockroach with its head cut off can live for 9 days, and the cause of death after 9 days is starvation.
1 1. Giraffes don't cough.
12. Owls are the only birds that can distinguish blue.
13. The whale's heartbeat is only 9 times per minute.
14. On average, an adult is 0.4 inch taller in the morning than at night. Because during the day, the cartilage of the spine
Easily oppressed.
15. We have been drinking water for 300 million years.
16. Chocolate contains a chemical called phenyl. This can be done in your head when you are in love.
A thing).
17. Only 30% people will enlarge and narrow their nostrils.
18. English contains the largest number of words in all languages, with nearly one million words, while German vocabulary is less than180,000 words.
French is even worse, less than 10 thousand words.
19. The sex of an adult eel will change from male to female, and it will change several times in its life.
20. The draft blueprint for the Eiffel Tower covers an area of over 65,438+04,000 square feet.
2 1. According to a law passed in Britain in 1845, suicide is a very serious crime, and the heaviest one can be hanged.
Death penalty.
22. Astronauts can't cry in space, because tears can't flow without gravity.
The length of the chameleon's tongue is twice as long as its own.
24. The people who use toothpicks most often are Americans.
25. Blind chameleons still have the ability to change colors to adapt to their surroundings.
26.27% of American male college students think that life is a meaningless hell on earth.
27. A normal person's eye muscles need to exercise 10000- 15000 times a day on average.
28. The elephant will still stand after death.
29. Some insects can live without their heads 1 year.
30. It took Leonardo da Vinci 12 years to draw the lips of the Mona Lisa.
3 1. When glass is broken, the maximum speed of glass fragments can reach 3000 miles per hour.
32. Cows can supply more milk when listening to music.
Roses picked in the afternoon last longer than those picked in the morning.
34. The tiger shark's embryo has to go through a fierce struggle in the mother's womb, and finally the baby tiger shark can be born alive.
35. A 70-pound octopus can pass through a hole the size of a silver coin because they have no spine.
Beethoven used to wash his face with ice water when he was sitting and writing songs. He believes that this will help his brain to make better things.
37. The stick insects in Indonesia are the largest insects in the world, some of which are 65,438+0 feet long.
38. Men's bodies contain more blood than women's bodies. Usually a man's blood can be as high as 1.5.
Sharon, but women only have 0.875 gallons.
39. The inventor of parachute gave his first parachute jump to a dog.
40. The wing length of a Boeing 747 is exactly the distance of the Wright brothers' first flight.
4 1. A big Japanese crab may be as long as 12 feet.
42. Sharks can only detect one millionth of blood in water.
43. The original meaning of "samba" in "samba dance" is "grinding navel together".
Children grow faster in spring.
45. Do you know how much water from the Amazon River flows into the Atlantic Ocean? In the Atlantic Ocean within 0/00 mile from the estuary/kloc-,the water you drink is still fresh water.
46. Newborn turkeys need parents to teach them how to eat, or they will starve to death.
47. The moon weighs 810 billion pounds.
Bats are the only mammals that can fly.
49. A caterpillar has more than 2000 muscles.
50. Hippos run faster than people.
2. Popular science knowledge suitable for the first grade of primary school.
Safety knowledge
Small knowledge of fire safety
First, LPG cookers should not be placed in bedrooms, offices, balconies, warehouses, auditoriums and other public places to prevent air leakage and fire.
Second, correctly grasp the use of the switch, wait for the fire, don't wait for the fire, remember to turn off the valve and switch after use, and replace the valve in time if it is broken. Don't let children use cookers or play with switches at will.
Third, when using liquefied gas, someone should look after it and stay away from it. Pay attention to adjust the size of the rotor at any time to prevent the soup from overflowing and extinguishing the flame or being blown out by the wind, resulting in air leakage.
Fourth, liquefied gas tanks should be upright, not upside down, and cannot be cooked or roasted with fire.
5. If there is air leakage, measures should be taken immediately: open doors and windows, ventilate with a fan (but not an electric fan), and then find the leaking part.
Basic knowledge of fire fighting
(1) isolation method: This is a method to eliminate combustible materials.
(2) Asphyxiation method: prevent air from flowing into the combustion zone, reduce the oxygen content in the air, and make the fire source go out under the condition of insufficient oxygen.
(3) cooling method: spray water or other fire extinguishing agents on the combustible materials to lower the temperature of the combustible materials below the ignition point and force the combustion of the materials to stop; Or spray water and fire extinguishing agent to combustible materials near the fire source to reduce the temperature of combustible materials and avoid the expansion of the fire.
(4) inhibition method.
I hope this helps.
3. Students' scientific knowledge
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.
4. Encyclopedia of first-year scientific knowledge
Small scientific knowledge
1. Rabbits beat the ground with their legs to send messages. Most of them beat the ground with their hind legs, which is a way for them to express their feelings to the female rabbits.
2. The biggest monkey in the world is a baboon and the smallest monkey is a bonobo.
3. The real name of "Four Elephants" is Elk, which is a rare animal in China.
4. 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.
5. 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.
5. Small scientific knowledge should be concise, reasonable and novel.
Scientific knowledge of primary school students 1. 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. 2. The biggest monkey in the world is a baboon and the smallest monkey is a bonobo. 3. The real name of "Four Elephants" is Elk, which is a rare animal in China. 4. Why should sorbet take risks? The reason why sorbet bubbles is that there is a lot of invisible water vapor in the outside air. When it meets a very cold sorbet, it will liquefy into droplets and surround it when it is cold. The sorbet seems to be bubbling. 5. Why do sunflowers always face the sun? 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 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. 6. 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. 7. How do bees make honey? Bees spit the sweet juice of flowers into an empty beehive. At night, they suck the sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 100~240 times before it becomes sweet. 8. Why do the stars twinkle? We see the stars shining, not because of the luminosity changes of the stars themselves, but because of the occlusion of the atmosphere. The atmosphere is between us and the stars. When a star 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. 9. Why do people yawn? When we feel tired, our bodies have produced a lot of carbon dioxide. When there is too much carbon dioxide, we must supplement oxygen to balance our needs. Because these residual carbon dioxide will affect the functional activities of our body, our body will send out a protective reaction at this time, so we yawn. Yawning is a deep breathing action, which will make us breathe in more oxygen and expel more carbon dioxide than usual, and also achieve the effect of eliminating fatigue 10.00000000 1003 The snake has many scales, which is the outermost 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 upward 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! 1 1. Why does hair turn white when people get old? 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! 12. 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. Fireflies shine not only for lighting, but also for courtship, vigilance and trapping. This is also a communication tool for them. Different kinds of fireflies have different luminous modes, luminous frequencies and colors, so that they can convey different information. When you are hungry, you will make a purring sound. 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. 14. 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. 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. Why can't the food in cans go bad easily? Lunch meat, black beans and ketchup beans are all delicious canned food. They can be kept for a long time and are not easy to go bad. Because the can is sealed, bacteria can't get in. When people make canned food, the air inside is pumped out and then sealed. Without air, even if the food inside is stained with a little bacteria, they can't survive or reproduce! 16. 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. 17. Why does the lizard keep bouncing when its tail is broken? In order to protect themselves, many lizards also protect their eyes and ears; On the other hand, when some lizards are attacked, their tails will be broken due to the severe contraction of their muscles. Some nerves in the broken tail are still alive and 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 continue to live. 5438+08, why is the squirrel's tail so big? Don't look at the relaxed mouse tail! The squirrel's tail played a great role when it jumped on the tree. 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 protective role in winter, tightly surrounding the squirrel's body, which is convenient and practical. Why can't a human thumb have one or three knots? The average person has five fingers, each with a different length. However, has anyone noticed that besides the thumb, other fingers are also there.
6. Primary school students' scientific knowledge is very simple.
2. If bitten by mosquitoes, you can apply soapy water on it to stop itching. Because the mosquito bites will spit an acid there, and soapy water is alkaline, so the acid-base combination. 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 muscles of the snake 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.
12. 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. 13. Why can't a person have one or three thumbs? 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! 14. 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! 15. Why are most seawater blue and green? Looking at the sea, it is often found that the sea water is blue.