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Scientific topic composition
In real life or work and study, everyone has tried to write a composition. According to the characteristics of writing proposition, composition can be divided into propositional composition and non-propositional composition. Then the question comes, how to write an excellent composition? The following are nine short articles on scientific subjects that I collected for reference only. Welcome to reading.

As we all know, in ancient times, feudal superstition was a curse that bound people's thoughts, which led people to keep pace with the times. I don't know that there is such a thing as "science". Then China fell from one of the four ancient civilizations to the end of the world.

In the Southern Dynasties, Zhu's viewpoint of "knowing knowledge by things" kept people out of science. At the same time, it has curbed people's pursuit of nature and scientific development, and made China take a big step backwards.

However, with the leap of the times and the continuous progress and development of social economy, people's minds are gradually liberated, thus starting the road of exploring science. Gunpowder used to be used to make firecrackers, but now it is used to defend the enemy; From the previous raft to the present ship; From the previous carriage to the present car, it proves the help of science to people and also embodies the value of science.

The development of science today is also closely related to our lives. For example, Newton was sitting under a tree and an apple fell and hit him, which made him think. Finally, he successfully proved the existence of gravity through experiments, which is a discovery of great significance to human beings and the world. Another example: the alternation of day and night in our lives, through people's research, has also found the law hidden behind this phenomenon. Everything we use, see and even eat in our lives has a great connection with science, and many scientists are involved in it.

No matter from the history of human civilization or observing the world around us, we can find the shadow of science. It can be said that from the moment science was born, we never stopped pursuing perfection, just as we never stopped exploring science. Since the birth of science, it has taken the benefit of society as its own goal and the direction of progress. However, we are enjoying the convenience brought by science. What are we doing? Most of us just accept it. Therefore, we should love science more, devote ourselves to science, invent more products and serve mankind.

Our ancestors were pioneers of scientific inventions, and our Chinese nation is also a nation full of wisdom. Our ancestors invented gunpowder, papermaking, printing and compass, which made great contributions to human civilization and laid the foundation.

Science broadens our horizons and increases our knowledge. I know, I like it!

Science entertains children and relaxes their lives. I know, I like it!

Science has created a beautiful life that belongs to us. I know, I like it!

It's sultry today. In the afternoon, my parents and I went shopping at a discount and took a taxi home. When I got on the bus, the air conditioner was on, and the weather was cool. When we get home, it's time to get off. As soon as I got off the bus, I saw my father's glasses "sweating" and foggy, just like a layer of white gauze. Dad said he couldn't see anything, so he took off his glasses, wiped them under his clothes and put them on again.

I think it's strange that my father's glasses can still be seen clearly in the car. Why does he get foggy when he gets off the bus and can't see anything clearly? I asked my father what was going on. Dad said to take me home to do an experiment, and I would know the answer after the experiment.

After dinner in the evening, I urged my father to take me to do the experiment quickly. He first asked me to prepare the materials for the experiment: a glass, some ice cubes and a glass of water. It's too simple. I got the materials ready in less than a minute. I have six ice cubes. Then, I began to do experiments:

I put the ice cubes in the cup first, and then pour some water into the cup. Dad asked me to look at the glass carefully to see what would happen. I sat on the sofa and stared at the glass with my eyes wide open. After a while, I found it was foggy and sweaty outside the glass. The ice in the cup slowly melts, and more and more "sweat" appears outside the cup. Finally, after a few minutes, the whole outside of the glass was wet and the water in the glass could not be seen clearly. I think the water in the cup is so cold, and the outside of the cup has been sweating. Why?

Looking at my strange appearance, my father finally told me the answer. Because the temperature outside the glass is very high, the water vapor in the air will adhere to the outside of the glass and condense into water droplets when it meets the cold glass, so we "sweat" when we see the glass.

Now, I know why my father's glasses "sweated" when he got off the bus! Because of the high temperature outside the car and the cold inside, when dad got off the bus, the water vapor in the air attached to his cool glasses and condensed into water droplets, so the glasses "sweated"!

I am so happy that I finally understand this scientific truth!

30,000 worlds, no surprises. In class today, Teacher Lin said, "Did you hear me say' paper buds blossom'?"

After a while, everyone gave a chorus of "hmm". "Today, I will take you to do an interesting experiment. The name of the experiment is' paper bud flowering'. " The teacher picked up the schoolbag, took out a bag of watercolor pens from the schoolbag and took out a piece of paper in the shape of flowers. Then he took out a blue marker from his watercolor pen bag and drew his favorite color on the paper with the pen, and the paper bud was ready. Then the teacher folded the petals.

"In the future, everyone will gather here to watch." The teacher picked up a basin of water and put it on the platform, and the students flocked to the platform like a flood.

"Now I put the flowers on the water and put them smoothly." The teacher said seriously.

There was silence in the classroom, and all the students stretched out their necks like geese, staring at the water unblinkingly. That bud is like a little girl who just woke up from sleep. It stretched out first, stretching out one petal, then another, and soon spread out. It looked at us curiously and stared at it.

"Do you want to experience this experiment?" The teacher said.

"think!" We say.

"I'm ready for you." The teacher said mysteriously.

Everyone got a paper bud painted with pigment. As soon as I got the paper bud, I couldn't wait to fold it.

The teacher said, "Let's put the paper buds in the water together."

We did as we were told, and as soon as the paper buds entered the water, they rushed to bloom. They walked up bit by bit, looked up curiously, and then looked around slowly, as if they felt very fresh about everything around them. Those colorful flowers compete with each other and have the momentum of "spring can't close the garden". It took about a cup of tea, and all the paper buds showed charming smiling faces. These paper flowers are like a little girl lying lazily on the water.

In fact, this experiment is a physical phenomenon. The main component of paper is plant fibers, which are tiny capillaries. After the paper meets water, the water rises along the capillaries in it, making the fiber full, so the original folded petals open.

We suddenly realized that life is full of science!

Science is actually around us.

In the evening, I take off my clothes and get ready for bed. The strange sound of "wow-ah-ah-hiss" is endless. It turned out to be an electric shock. I touched it six or seven times in a row. But some people say that it is not "electric shock", but static electricity. I thought to myself, "hearing is empty, seeing is believing." What is static electricity?

On Sunday, I struggled to find a story about static electricity. The book says: "If we wear chemical fiber clothes and insulated shoes to move on the insulated ground, the static electricity on our bodies can reach several thousand volts or even tens of thousands of volts." I was so shocked that I couldn't help shivering. Pause and continue to look down. "When people come into contact with metal, electrostatic shock will happen!" Oh, this is the principle of triboelectrification!

So how is static electricity generated? My curiosity and thirst for knowledge are getting stronger and stronger. I have to ask my big cousin for advice. My cousin patiently explained to me: "Static electricity is due to the fact that when different objects touch each other, one object loses some electrons and becomes a positive charge, and these electrons are transferred to another object, making it a negative charge. If the charge is difficult to neutralize in the process of object separation, the charge accumulated on the object will form static electricity. " "Oh, I see. Thank you for your advice. " Then go home and do the experiment with a brush.

Is there any way to eliminate static electricity? I took a dozen cable ties and let them rub to generate static electricity. Because of static electricity, they spread everywhere. I can't think of any clever tricks at the moment. I will touch the mouse with a blind cat. Touch it! I put it next to the lighted candle, and a miracle appeared. The loose bandages hung down slowly and gathered together. "Hey? What the hell is going on here? " I've thought about it over and over again, but I can't come to a conclusion.

In order to get the answer, I had to ask my learned sister for help again. Sister said: "flame is used to eliminate static electricity, because flame can ionize air molecules into positive ions, negative ions and electrons." The negative charge of the bandage is neutralized by the positive ions brought by the flame. " I was in a daze. But anyway, I added a little knowledge-flame can eliminate static electricity.

This day, the harvest is really not small! I secretly said to the static electricity in my heart, "Hey, it turns out that flame is your natural enemy! I'm not afraid of you now. It's easy to deal with you, hahaha! " Ah! There are so many interesting sciences around us. My thirst for knowledge is growing, and science is wonderful!

During the summer vacation, my father took me swimming in the Olympic Sports Center. When I came to the swimming pool, I took off my underwear and went swimming. I swim happily. Suddenly I felt a little pain in my ear, but I felt that it was nothing serious, so I endured it and swam down for a while. Oh, no, my ear hurts again and I don't want to surface. So I asked my father, "Dad, why do I feel my ears hurt when I swim?" Dad told me, "Maybe you dive a little deep. The pressure of the water is too great for your ears, so it hurts."

So I became curious about the pressure of water and wanted to know what determines the pressure. When I got home, I flipped through "100,000 Why", and there were too few things written on it to understand. I looked up the information on the Internet and learned that the pressure of water is determined by its depth. The deeper the water, the greater the pressure, and the shallower the water, the less the pressure.

To this end, I did an experiment. The materials are: 1 rectangular vertical carton filled with milk, 1 rolled tape, 1 nail, 1 flat plate.

I put away the milk carton and poked three holes in both sides with nails. The positions of the three holes are bottom, middle and upper respectively. Then seal the three holes with adhesive tape, fill the carton with water, put the flat plate under the perforated side and tear off the adhesive tape. Do you know what happened? Is there a difference between three-hole water spraying? Of course not. The water from the bottom is sprayed farthest, followed by the water in the middle, and the water from the top is sprayed closest. This proves that the pressure of water varies with the depth of water. The deeper the water, the greater the pressure, and the shallower the water, the less the pressure. Therefore, the depth of my swimming pool is different, and the pressure felt by my ears is different.

In order to know what other factors are related to stress, I did another small experiment: I inserted a straw into the mouth of a small paper box and plugged it tightly. Then I use a straw to add water to the carton. When the water reached the suction pipe, the bottom of the small carton cracked. After many experiments, the results are the same. It turns out that water pressure is also related to weight. Because the bottom of the carton bears the maximum weight of water, the water pressure is the greatest, so the bottom of the carton cracks.

Pressure is everywhere, including water pressure and atmospheric pressure, which are closely related to our lives. The pressure is far away and close at hand!

I feel that the world is wonderful since I was a child, and I am curious about many things. For example, what does the tree "breathe"? Why do people fly away as soon as they get close to flies ... then they go to school, and now a lot of knowledge that they didn't understand before is slowly' understood'. In science class, I know that the "small nose" of a big tree is its leaves, and the big tree breathes on the leaves. In extracurricular books, I learned that flies can observe 360 degrees, so they can detect the smallest activities around them as quickly as possible. So when people get close, it will fly away immediately ... But there are still many phenomena around me that make me curious.

One day, I finished my homework and went to the balcony to see some goldfish raised by my grandfather. I brought fish food to feed the small fish, and then I lay down in front of the fish tank to watch the small fish eat. Suddenly I found out that the goldfish I saw in the water through the fish tank was much bigger than the goldfish I just saw through the water. So, I stood up again to see the fish through the water, and the little goldfish became smaller again. I was shocked and shouted, "Mom, no, the little fish has become a Transformers!" " "My mother heard me crying and ran to see it. I said to my mother anxiously, "Fish will get bigger and smaller. "After listening to my story, my mother smiled and said to me," It's not that small fish will get bigger and smaller, but that light is becoming a magical magic! "I was more curious and asked," How can light do magic? " So my mother found the encyclopedia and turned to the page about light. I couldn't wait to pick up the book and read it. After reading the book, I finally understand that it is really not the small goldfish that will become bigger and smaller, but the principle of light refraction: when light hits from one medium to another, the propagation direction of light changes at the interface, and some light enters the second medium. This phenomenon is called light refraction. I also learned from books that light can become other "magic". For example, when I look in the mirror, I hold it in my right hand, while when I look in the mirror, I hold it in my left hand. This is the principle of light reflection. Light can also do a lot of magic!

If there is no science in life, there will be no fun, no exploration and pursuit; The world is full of mystery, full of magic ... science is like the key to solve the mystery, and all questions need to be answered without it. We need to keep exploring in the future study in order to know more scientific mysteries.

On Sunday, I saw my father's dusty leather shoes and couldn't help sighing, alas! It seems that I should be a coolie again. I picked up my father's dusty leather shoes, painted them with shoe polish and polished them carefully, thus reappearing my youth. Why? I don't doubt it.

So I found a new pair of shoes to compare with the old ones. I first touched the uppers of two pairs of leather shoes and found that the surface of the new shoes was smoother than the old ones. After the old leather shoes are painted with shoe polish, careful observation shows that although they are much brighter, they are still not as good as the new ones. Is there a relationship between the brightness and smoothness of leather shoes?

I went to get a pair of old leather shoes, which looked uneven under a magnifying glass. Then I applied shoe polish to the rough areas 1 and 2 of the leather shoes, and wiped them carefully. The area 2 was not applied as a blank control. I found that the surface of 1 area was much smoother after wiping, and it was brighter in the sun than that of area 2. Why are there such big differences between them?

So I went to ask my father and learned that the surface of leather shoes is not absolutely smooth, but if it is old leather shoes, it is even more uneven, so that it can't reflect light in a certain direction and looks very dim. And some small particles in shoe polish just fill the pits of leather shoes. If the cloth is used to polish the shoe polish, so that it is coated more evenly, the surface of the leather shoes will be smoother and more reflective.

Through the experiment, I finally know the secret of shoes getting brighter and brighter.

One day, I went to the suburbs to ride a bike. Suddenly, I saw a crawling black, so I stopped my bike and squatted down curiously to observe it carefully. It turns out that the army of ants is crawling to the top of the hill.

After a while, Xiao Ming came by bike, saw me squatting on the ground, stopped the car and asked me what was wrong. I looked up and said, "Look down, too. The ants are moving." Xiao Ming squatted down and looked at it and said, "I suggest we go home quickly." It is going to rain soon. " I gave him a white look and said, "Cut! Xiao Ming, don't lie to me. How can it rain? Look at the clear sky in Wan Li, just say it's going to rain! " Hearing this, Xiao Ming ignored me and rode back by himself. I continued to wander outside by bike. Soon, the sky suddenly became cloudy. Then I remembered Xiao Ming's words, and I sped up my bike ride back. But I was only halfway through the ride when it began to rain. I was soaked through. When I got home, my mother said, "Oh, go and change it!" "I really regret that I didn't listen to Xiao Ming, but I also feel very confused: What is the relationship between ants moving and rain? I took this question and looked it up online. It turns out that ants already know the change of temperature in advance, and when it rains, they will move to a higher place. I also learned a proverb: ants move the snake aisle, and heavy rain is coming.

Nature is wonderful and there are many mysteries waiting for me to discover. As long as we pay attention to observation, we are sure to discover the little secrets in life.

The continuous improvement of life and the continuous prosperity of cities are inseparable from the benefits brought by science and technology. In life, there are also many things around us that have been changed by learning.

One day when I was a child, I took a bath at home. The bathtub is full of water, and I am comfortable in it, humming a tune. Just when I was happy, a drop of cold water suddenly landed on my nose and scared me. What happened? I looked up at the ceiling and found that there were many small drops of water lined up, and a few drops were falling. I didn't understand what was going on, so I went to consult my mother. My mother said: "The water drops on the ceiling are the water vapor emitted from the bathtub. When the ceiling is cold, it will condense, and the surface of the ceiling is very smooth, so it will gather more and more, and it will fall down at a certain time." "Oh, I see." It suddenly dawned on me that another idea flashed through my mind: dripping water on the ceiling would make swimmers feel uncomfortable. How can I keep the ceiling from dripping?

As soon as I turn my head-if the ceiling of the bathroom is arched, the water droplets formed on the ceiling will flow down along the arch, and then a small sink will be made at the bottom of the arch to connect with the sewer, which can completely prevent the water droplets from falling off the ceiling during bathing. Yes, let's do it.

In the evening, I told my mother this idea. My mother said, "shall I take you to the sauna today?" "But I have washed it. Tomorrow? " "No, go today. You will understand when you go. " I didn't know what was in my mother's gourd, so I had to follow her, but when I got to the sauna center, I understood, because the ceiling there was arched and the water drops on it flowed down the beautiful dome. I scratched my head and smiled and said, "I see." My mother patted me on the shoulder and said, "Smart! This is the science around us. Scientific principles are everywhere in our lives and are closely related to our lives, so you should study hard, master more knowledge and meet new challenges. "

As long as we observe carefully, think more and pay attention to life, we can learn a lot of scientific knowledge and broaden our horizons.