For example, the largest celestial body in the solar system is a comet, commonly known as a comet, which consists of a coma head and a coma tail, of which the coma head consists of a nucleus and a coma. The diameter of the comet nucleus is about 10 km, and the huge air mass around it is huifa, with a diameter from tens of thousands to hundreds of thousands of kilometers.
Wei Hui is even longer, reaching hundreds of millions of kilometers. I also know why the sun shines and heats up. This is because the sun is a star and the largest celestial body in the solar system. This big gas ball has been releasing a lot of light and heat.
It is because of the sun that the earth has warmth, light and life. The surface temperature of the sun is about 6000 degrees Celsius, and the central temperature is150,000 degrees Celsius.
This is due to the intense atomic reaction inside the sun. The sun consists of more than 70 elements, the main component of which is hydrogen.
The high temperature and pressure inside the sun are the interaction between emotional nuclei there, thus releasing a lot of light and heat. I also know that Mars is one of the eight planets in the solar system, and scientists call it the "twin brother" of the earth.
This is because Mars has many characteristics similar to that of the Earth. Looking through a telescope, you will find that Mars is simply a "sphere".
Its poles are white polar crowns, just like the snow-covered north and south poles on the earth. Mars, like the earth, revolves around the sun at a certain angle.
In addition, a day on Mars is 39 minutes and 35 seconds longer than a day on Earth. The difference is that a year on Mars is 687 days, which is 1.9 times that of the earth.
Like the earth, there is an atmosphere on Mars. The universe is magical. When I grow up, I must become a scientist to study the mystery of Mars. Can humans live on Mars in the future? Please believe me, I will study hard.
2. The third unit below the sixth grade of primary school is a popular science article. Who can help me write a 450-word article based on this My mother left me a riddle: "Zhuge Liang is in Nanyang, sitting firmly in the army account." Arrange the eight diagrams and catch the flying generals. " This myth tells us that spiders only eat living things, doesn't it eat dead things? This aroused my interest and I did the experiment.
I caught a little spider from the corner and put it in a box (with holes around it and glass on it for easy observation). Before the spider could weave a web, I picked up a dead bug and a dead fly and put them in front of the spider. The spider ignored them, then hit the box with her hand, and the spider crawled in other directions.
In order to find out whether spiders eat dead flies completely, the next day, I came to the box to observe and saw that dead insects and dead flies were still in their original places, but there was a net in the corner of the box, and the spider was lying quietly on the net. At this time, I thought: Is it because there is no net that the dead flies and insects didn't eat it yesterday? So I picked up the dead fly and gently put it on the net, but the spider still didn't move. Then, I gently touched the edge of the net with my pen. Gee, the spider seems to have a reaction and started to climb in a trembling direction. I took the pen back and the net stopped shaking. The signal was interrupted and stopped. Soon, the spider climbed to the center of the web again. I touched the dead fly's body on the net with the pen tip again, and the net began to vibrate, and spiders began to crawl here. I took back the nib again and the spider stopped. Like last time, after a while, the spider climbed to the center of the web again. Oh! I finally understand that spiders feel by the vibration of their webs and prey by weaving them. So, I recorded the experimental results.
In order to prove that spiders feel through the vibration of their webs, I did another experiment. Put the pen tip on the dead fly on the net and vibrate for a long time. The vibration of the web is getting bigger and bigger, and the spider seems to feel stronger and stronger. Spiders will come in a hurry. When a spider meets a fly, I will take back the pen tip, only to see that the spider's tail will soon spit out sticky silk to tie the fly, and then look at the spider's back, as if sucking the fly. Soon, there was a complete empty shell left on the Internet. This experiment proves that spiders eat moving insects.
Our secret group went to the library and bookstore to consult a lot of books about spiders. Among them, General Zoology wrote that spiders are carnivores, and their food is mostly insects or other arthropods. But the mouth has no upper jaw, so you don't swallow solid food directly, but suck it slowly. When insects and other animals come into contact with the net, they will struggle desperately on the net to make the net silk vibrate, so that spiders will find it soon. Spiders will crawl along the longitudinal silk to their prey, wrap the prey with spider silk and fix it on the net. First, the venom secreted by poisonous glands in claws is injected into the captured prey to kill it, then the digestive enzyme secreted by midgut is injected into the captured tissue torn by claws, which is quickly decomposed into juice, then inhaled into digestive tract, and finally eaten the remaining body shell. These fully prove that flying insects make the spider's web vibrate, and the web vibration will make it feel, and the spider will catch its prey if it feels. So it is confirmed that spiders only eat live animals, not dead insects.
Broadly speaking, all works that discuss the contents of science and technology are called scientific works, such as original works, briefings, comprehensive reports, progress reports, literature reviews, comments, monographs, compilations, textbooks, popular science books and so on. However, only the original work and its introduction are original, major and primary, involving inventions and other intellectual property rights.
Others are of course important, but they are all processed, developed and written for specific application purposes and objects. Let's just talk about some experiences in writing original works, and also talk about some experiences on how to make a good academic report. When discussing the original paper writing, I'm not going to talk about all kinds of rules and regulations about manuscript writing. Today, Dingde Cultural Workshop talks about the problems and experiences that are easy to occur in writing, and it is also the standardization of writing ethics and writing content.
Go home from school on Friday, just wash your hands, put down your schoolbag and do your homework. Suddenly, I remembered that I asked my grandmother to help me buy a math science book yesterday, so I asked, "Grandma, did you help me buy a book?" "Of course." Grandma picked up two books, "You said" Ma Xiaotiao Playing Mathematics "was good, so I bought it. But this book is only in the sixth grade, so I have to buy this one. " I picked up the book, flipped through it and put it on the table. "This book is OK, thank you!" I said to grandma.
Suddenly, my grandfather picked up the book I put at hand and said, "Hummer, this book is good. If you can do it, then you have exceeded the level of the fifth grade! " ! I'll test you a simple one first! ""yes, I will succeed! "I said confidently." Listen carefully. The title reads: "Grandpa turned a page and said," Just finished the men's 800-meter race, Ma Xiaotiao was anxious to tell everyone the result. Player A said,' C is in front of me.' The students who won the third place also joined in the fun:' A is not the fourth.' Finally, Zhang Da added: "Their numbers are different from the rankings." Ok, you calculate their ranking. "I'll get a pen and count it on the draft paper. "It's okay! See if I'm right! A is the first, that is, the second; B is the fourth place; C is the first place; Ding is the third place! " "Ha ha, yes, how do you calculate it?" Grandpa looked at me with a smile. "Of course I know. A said that C was faster than himself, and the third classmate said that he was not the fourth, nor could he be the third, but only the second. C is faster than a and is the first. Because the numbers are different from the rankings, Ding is the third and B is the fourth. " "Not bad! Smart! " Grandpa praised me, "but you can't be proud. Mathematics is everywhere and the most wonderful. You must study hard! " ""hmm! " I also smiled, "I know! As teacher Zhang said, the more you know about mathematics, the more you don't know. Math, it's amazing! "
4. The sixth grade math composition is full of fun, and there are many interesting things in our math kingdom. For example, in my ninth exercise book, there is a thinking question that reads: "A bus goes from Dongcheng to Xicheng at a speed of 45 kilometers per hour and stops after 2.5 hours. At this time, it is just 18 km away from the center of the east and west cities. How many kilometers is it between East and West? When Wang Xing and Xiaoying solve the above problems, their calculation methods and results are different. Wang Xing's mileage is less than Xiao Ying's, but xu teacher said that both of them were right. Why is this? Have you figured it out? You can also calculate the calculation results of both of them. " In fact, we can quickly work out a method for this problem, that is: 45*2.5= 1 12.5 (km),112.5+18 =130.5 (. In fact, we have neglected a very important condition here, that is, the word "Li" mentioned in the condition is "just 18 km from the center of the east and west cities", and it does not say whether it has not yet reached the midpoint or exceeded the midpoint. If the distance from the midpoint is less than 18km, the formula is the previous one; If it is greater than 18km, the formula should be 45*2.5= 1 12.5 (km), 1 12.5-65448. So the correct answer should be: 45*2.5= 1 12.5 (km),12.5+18 =130.5 (km),/kloc-. Two answers, that is to say, Wang Xing's answer and Xiaoying's answer are comprehensive.
In daily study, there are often many math problems with multiple solutions, which are easily overlooked in practice or examination. This requires us to carefully examine the problem, awaken our own life experience, scrutinize it carefully, and fully and correctly understand the meaning of the problem. Otherwise, it is easy to ignore other answers and make a mistake of generalizing.
About "0"
0, can be said to be the earliest human contact number. Our ancestors only knew nothing and existence at first, and none of them was 0, so 0 isn't it? I remember the primary school teacher once said, "Any number minus itself is equal to 0, and 0 means there is no number." This statement is obviously incorrect. As we all know, 0 degrees Celsius on the thermometer indicates the freezing point of water (that is, the temperature of ice-water mixture at standard atmospheric pressure), where 0 is the distinguishing point between solid and liquid water. Moreover, in Chinese characters, 0 means more as zero, such as: 1) fragmentary; A small part. 2) The quantity is not enough for a certain unit ... At this point, we know that "no quantity is 0, but 0 not only means no quantity, but also means the difference between solid and liquid water, and so on."
"Any number divided by 0 is meaningless." This is a "conclusion" about 0 that teachers from primary school to middle school are still talking about. At that time, division (primary school) was to divide a copy into several parts and figure out how many there were in each part. A whole cannot be divided into 0 parts, which is "meaningless". Later, I learned that 0 in a/0 can represent a variable with zero as the limit (the absolute value of a variable is always smaller than an arbitrarily small positive number in the process of change) and should be equal to infinity (the absolute value of a variable is always larger than an arbitrarily large positive number in the process of change). From this, another theorem about 0 is obtained: "A variable whose limit is zero is called infinitesimal". On the tiled floor or wall, adjacent floor tiles or tiles are evenly attached together, and there is no gap on the whole floor or wall.
For example, a triangle. A triangle is a plane figure composed of three line segments that are not on the same line. Through experiments and research, we know that the sum of the inner angles of the triangle is 180 degrees, and the sum of the outer angles is 360 degrees. The ground can be covered by six regular triangles.
Look at the regular quadrangle, which can be divided into two triangles. The sum of internal angles is 360 degrees, the degree of an internal angle is 90 degrees, and the sum of external angles is 360 degrees. The ground can cover four regular quadrangles.
What about regular pentagons? It can be divided into three triangles, the sum of internal angles is 540 degrees, the degree of one internal angle is 108 degrees, and the sum of external angles is 360 degrees. It cannot cover the ground.
Hexagon can be divided into four triangles, the sum of internal angles is 720 degrees, the degree of one internal angle is 120 degrees, and the sum of external angles is 360 degrees. The ground can cover three regular quadrangles.
A heptagon can be divided into five triangles. The sum of internal angles is 900 degrees, the degree of internal angles is 900/7 degrees, and the sum of external angles is 360 degrees. It cannot cover the ground.
From this, we come to the conclusion. An N-polygon can be divided into (n-2) triangles, and the sum of internal angles is (n-2)* 180 degrees, the degree of an internal angle is (n-2)* 180÷2 degrees, and the sum of external angles is 360 degrees. If (n-2)* 180÷2 can be divisible by 360, then it can be used to pave the way; If not, it can't be used to pave the road.
Not only can you cover the ground with a regular polygon, but you can also cover the ground with more than two or three kinds of graphics.
For example: regular triangle and square, regular triangle and hexagon, square and octagon, regular pentagon and octagon, regular triangle and square and hexagon. ...
In real life, we have seen all kinds of patterns composed of regular polygons. In fact, many patterns are often composed of irregular basic graphics.
5. A popular science composition (suitable for the sixth grade of primary school) requires students to answer urgent questions: the legend of "the Goddess Chang'e flying to the moon", which has been circulating in China for thousands of years, began to come true in this beautiful autumn.
With the first lunar probe independently developed by China, Chang 'e-1 satellite, flying into space, China astronauts who are constantly striving for self-improvement will engrave a brand-new height of the Chinese nation in space. Lunar exploration is the third milestone of China's space exploration.
It marks the first step for China's space exploration after the artificial earth satellite flight and manned space flight. Deep space exploration is the exploration of planets and their satellites, asteroids and comets in the solar system, the Milky Way and even the entire universe outside the solar system, and has become a hot spot in international space activities.
The Chang 'e-1 satellite launched today will fly to the moon, which is 380,000 kilometers away from the Earth, increasing the longest flight distance of China artificial satellite from about 80,000 kilometers to 4. More than five times.
As a country where myths and legends such as "the Goddess Chang'e flying to the moon" and "Wu Gangfa Ghost" were born, the people of China have a strong desire to explore the truth of the moon since ancient times. As early as 3,000 years ago, our ancestors began to record lunar eclipses and predicted them before 1500 years ago.
However, in the true sense of modern lunar exploration, we are latecomers after all. 1959 10, the Soviet Union completed its first flight around the moon, and humans took photos of the back of the moon for the first time; 10 years later, in July, American astronaut Armstrong left the first human footprint on the moon, and with his own small step, he realized a big step for mankind.
Just like every progress in space exploration, independent innovation, catching up and leaping development have become the unremitting pursuit of China astronauts who came from behind. So far, lunar exploration activities have basically gone through such a gradual process: flying close to the moon, hitting the moon, exploring around the moon, and soft landing on the lunar surface ... following the principle of increasing technical difficulty.
China's first lunar exploration adopted the lunar exploration method, which directly crossed the first two stages. From 1958 * * to 1970, it took 12 years for the music of Dongfanghong to resound through space. It took 1 1 year from the establishment of manned spaceflight project in 1992 to the success of manned spaceflight in 2003; It only took more than three years from the start of the lunar orbiting project in early 2004 to the launch of Chang 'e-1 satellite today ... This shortened time shows that China astronauts are getting faster and faster on the road from a space power to a space power.
The huge lunar exploration project involving tens of thousands of people only cost 65.438+0.4 billion yuan. Diligence, selfless dedication, unity and cooperation constitute the unique and eternal theme of China's space industry.
Space is the space owned by human beings, and the space industry is the cause of all mankind. Adhering to the consistent aim of peaceful development of space resources and benefiting all mankind, the Chang 'e project in China was highly open from the beginning.
China announced that the data from the Chang 'e-1 satellite will be shared with scientists all over the world. This shows once again that China astronauts have contributed wisdom and strength to the human space industry with a high sense of responsibility.
Xiongguan Road is as iron as iron. Although human exploration of the moon has a history of nearly half a century, so far, less than 50% of the 123 lunar exploration activities have been successful.
This means that the "Chang 'e" trip to the moon, which is expected to be more than 1 10,000 kilometers, is by no means smooth sailing. We look forward to Chang 'e's good journey.
This is the wish of China astronauts, and it is also the expectation of the Chinese nation and even all mankind. 10 is the harvest season.
Four years ago, in June+10, 5438, the day after the Third Plenary Session of the 16th CPC Central Committee, Yang Liwei embarked on the voyage of China astronauts in Shenzhou 5. Today, three days after the victory of the 17th National Congress, Chang 'e-1 satellite flew to the moon with the dream of an ancient nation.
This is another new leap in China's space history. Two golden autumn and two grand events; Just as the Chinese nation stood at a new starting point on the road to Socialism with Chinese characteristics, so did China Aerospace.
6. Write an observation diary according to the popular science practice of how goldfish live (grade six).
In order to observe goldfish, I bought three goldfish, one with bulging eyes, one with white fat and one with white ash, like a little fat man; The other is orange stripes on the upper body, but the lower abdomen is white. The other fish is red all over. If you don't look carefully, you really think it's a mass of bright red blood. There is also a goldfish in colorful clothes, which looks like a small flower.
Goldfish swim with four things under their heads. When swimming, goldfish will keep swinging its tail. I find goldfish like to hide in the dark.
When it is hungry, I put a handful of goldfish's food, and they will scramble to eat it, regardless of the previous gentlemanly demeanor; But when it is not hungry, if you force it to feed, it will eat and spit it out, which will make you half dead, and no matter what it is doing, its eyes are always bulging.
Strange thing
These days, goldfish always float to the surface to exhale, which makes me puzzled. Why do goldfish always float and breathe? Guess what? It's a real mystery.
At noon, I came to see the goldfish and found that the goldfish in colorful clothes died. I cried sadly.
quick
The next day, I found that when I fed the fish, they wouldn't rush to eat like the sun, or even turn a blind eye to the food.
At noon, fish always have no appetite, which makes me feel very confused. I was fine yesterday, but I'm too worried to eat today.
I remember: Is it because they found a good friend missing? However, they were all very comfortable yesterday. I don't know if they didn't worry because they thought the little goldfish went out to play yesterday, but it's been so long. Why don't they put the fish back? !
Alas, I can't guess at all. Who can understand fish language? Help me ask why it has become so worrying, but who in this world can understand the language of goldfish?
7. Ask 1 the sixth grade composition about popular science fairy tales, and see a doctor on the earth.
On this day, a patient came to the Cosmic Center Hospital. He is the earth. Why does the earth want to see a doctor? Let me tell you something.
Dean Halley's comet asked, "Brother Earth, why are you here?" Are you also here to see a doctor? " The earth said, "I don't see a doctor." What am I doing here? " Halley's comet touched the earth's head and said, "Do you have a fever? Now that technology is developed, you should be healthier. Since you don't have a fever, it seems that you are really ill. Tell me what happened to you. " The earth said, "I have so many diseases that my eyes can't see clearly." Please give me treatment. " "This is no good. You have to ask the ophthalmologist Niu Langxing to treat you. " Then the earth came to the eye doctor Altair. Altair looked into the eyes of the earth and showed the earth the words on the eyesight tester. The earth shook its head to show that it could not see clearly. Niu Lang Xing said with a microscope, "Let me see what's wrong with you, your eyesight is so poor." When the Altair was observed with a microscope, a strong wind blew in the desert, flying sand and stones. No wonder your eyesight is so poor, so the earth put on 3680-degree myopia glasses and walked out of ophthalmology.
The earth came to the internal medicine department again and said happily, "How do you have time to go to the internal medicine department?" The earth said, "Stop fooling around and show me quickly. It's 47 degrees north latitude and 35 degrees east longitude." What happened? It stinks. Tian Ma Xing brought a microscope and said, I'll show you. After seeing it, Tianma Xing said to the earth, "That place is full of rubbish, dead cats, dead dogs, plastics, scraps of paper and other smelly things." Say that finish, xing Wu wear nose and say: "I want to vomit." The doctor brought perfume and put it in that place. Hearing this, the earth said, "It still stinks." Ma Tianxing said, "There is nothing I can do about it."
The earth has come to surgery again. The earth said to the surgeon Neptune, "I have a large yellow spot." Please show me. " Neptune looked at it with a microscope. It turned out that those places were deserts, and there was no life at all, leaving only dead stumps on the trees. The earth asked Neptune to treat him, but he said, "There is nothing I can do."
Finally, the doctors said in unison, "There is nothing we can do about it. Only humans can save you. Ask humans! "
Protect the earth, the earth is calling!
About today's composition in Unit 5, Grade 6, the teacher asked us to keep a diary. Let me talk about what happened today!
Before math class, I heard many students say, "It's so annoying to have math class!" I feel very strange about this. Why don't students like math class? I didn't know why until I asked my classmates. It turned out to be a math problem recently, and my classmates (including me) couldn't figure it out! I can't tell which problems are divided and which problems are multiplied. I think I am always confused, so I decided to put forward 200% spirit in this class!
But in class, the teacher asked us to do judgment questions. But I haven't been able to do it for a long time! What's going on here? How did I become an idiot! Ah ... I'm so bored! Forget it, listen to the teacher later!
In the course of the teacher's lecture, I found many places that I had neglected before, and I almost forgot all the knowledge I had learned before! But when the teacher was talking about division and multiplication, I became more and more fascinated! If you make a mistake, you still have several problems, all of which are division problems; Calculate the division problem as a multiplication problem.
After school at noon, I discussed math problems with my classmates. I found myself with many problems and couldn't tell the meaning of multiplication and division. After returning home, I asked my mother to give me some questions, and I searched carefully for the meaning of these questions. Oh, I see! After my hard study, I finally understand the significance of multiplication and division!
It turns out that "the fraction of a number is calculated by multiplication;" Knowing what the score of a number is and what the number is, the problem is calculated by division! "Then, my mother gave me the 10 question, and I got it all right! I also found some shortcomings of myself!
This time, I overcame another difficulty and took a successful step. I am very happy, because I found my own shortcomings and overcame them! From this incident, I found that the difficulty is not so terrible! As long as we work hard, no matter how big the difficulties are, we can overcome them!
9. Composition of earthquake science knowledge 100 Natural disasters, including man-made disasters, are man's greatest enemies. There are many natural disasters, such as earthquakes, acid rain, greenhouse effect and typhoons. Man-made disasters include fire, soil erosion and so on. As early as ancient times, people had no awareness of prevention, and they all prayed to God and Buddha for peace. With the development of society, people know how to protect themselves with scientific and practical methods and reduce the threat of disasters to life. This article will tell you how to use scientific methods to prevent earthquakes and reduce disasters, protect yourself and protect your home.
According to the survey, there are many major earthquakes in China, such as Dali earthquake in Yunnan/KOOC-0/5/KOOC-0/4, Haicheng earthquake in Liaoning/KOOC-0/975, Qiongzhou earthquake in Hainan/KOOC-0/605, Nan Di earthquake in Kangding, Sichuan/KOOC-0/786 and Tangshan earthquake/KOOC-0/986.
In fact, some disasters can be prevented. Before the earthquake, there will be some signs. For example, domestic animals such as horses will break free from the reins and run wildly outside; Hibernating snakes will come out of their holes; Bees will fly around; Dogs will bark, and some livestock will run around in circles; Rats move in groups ... these omens can let people know in advance that there will be an earthquake. If these animals are found to have these abnormal phenomena, we must first distinguish between the true and false, and then report to the Seismological Bureau to prevent them from leaving early.