Fourth grade scientific composition

In everyday life, everyone will inevitably touch or use composition. According to the characteristics of writing proposition, composition can be divided into propositional composition and non-propositional composition. Do you know how to write a good composition? The following are eight fourth-grade scientific compositions I have compiled, hoping to help you.

There is a book that I can't put down recently. I can't get tired of reading it over and over again. This book is a science volume (weather and climate).

Science volume (Weather and Climate) is one of the series of science volumes, which tells us about meteorology by combining cartoons and words. Starting with what meteorology is, this paper describes what disciplines meteorology studies, the relationship between human beings and meteorology, and the difference between climatology and astronomy. Then I talked about what is the Mediterranean climate, what is the subtropical climate and so on. Then talk about how various climate phenomena are formed, such as the "El Nino" phenomenon that people often say, how beautiful snowflakes are formed, how rainbows are formed, and what is the "heat island effect"? Then tell us where there is extreme climate in the world and how we humans can prevent climate diseases.

A boring knowledge, explained with vivid stories. The protagonists of the story are all familiar cartoon characters, such as jumping frog, fire hat, red kangaroo, white radish and so on. Vividly displayed various climate stories. For example, can you measure the weather by observing clouds? In this chapter, it is said that jumping frog jumps east and west and stains beautiful clothes. He hopes to get dressed and get ready to dry. When hanging clothes, sunflower said, you'd better hang them indoors, because it's going to rain! Jumping frog doesn't listen, but still enjoys the clouds in the sky. I smiled happily when I saw Yunxiang Wan and two puppies grabbing things. I don't know, it rained naively a few minutes later. Oh, dear! I got my favorite clothes wet. Now, I want to ask how the sunflower knows. Sunflower told him mischievously: There are many kinds of clouds: cumulonimbus, cirrocumulus, hook cirrus. Different clouds are formed due to different accumulated water in the clouds. I just saw the cirrus cloud thickening, which means that water accumulation is a sign of rain! If there are few cirrus clouds, the next weather may not change much! There are many such interesting stories.

Another feeling of reading this book is that you must pretend to understand and listen to suggestions. In the end, I still suffer. Because several cartoon characters in the book don't understand, they give different suggestions, either their things are broken, their bodies are harmed by the climate, and Dai sisters suffer. Haha, besides being happy, I also received the education of thinking and dealing with people.

This is really a rare good book! Comprehensive, rich, but not boring, very beautiful and durable. Learning more knowledge is a happy thing in life; Understanding scientific knowledge is an important thing in life!

Reading and reading, I seem to be in the scene and environment of all the characters in the book, and my mood fluctuates with their conversation. When I saw the losses caused by those bad weather, I couldn't help feeling nervous and worried. When I knew why such a climate was formed, I couldn't help but suddenly realize that I thought I had encountered such weather the day before, so that's it! There is no need to make a fuss about this situation in the future! This book left me a lot of room for knowledge and imagination. Swimming in the ocean of meteorological knowledge while reading a book. Rich knowledge makes me look like a hungry man looking for bread. When I saw new knowledge, I forgot about hunger. A lot of knowledge is accompanied by interesting pictures, which makes me laugh while increasing my knowledge. I am happy, and there is no pain that I don't understand.

I graduated from Hunan Agricultural University in 20xx, and after staying in the Provincial Institute of Agricultural Sciences for several years, I came to Huarong County, my hometown, and did something practical for my hometown, building a seedling greenhouse.

"Hello everyone, welcome to Sanfeng Temple seedling greenhouse, the key scientific research base in Huarong County!" This Friday, we welcomed a group of small guests in the nursery greenhouse. They all looked around curiously. At this time, I, an agricultural scientist, had to come out!

I led everyone to the hair generator, and everyone scrambled to ask, "What is this? What do you do? " I was very excited to see that everyone had such a strong interest in agriculture, so I gushed: "This is called a constant temperature germination system. When using this machine, we will spread seedlings-rice seeds evenly and use warm water of about 35 degrees to accelerate germination. " Everyone bowed their heads and observed in unison. Just then, I pressed a hidden button, and the faucet like a shower spouted water. Everyone was very surprised. Some took out their mobile phones to take pictures, while others kept taking notes. Seeing this scene, my mouth couldn't help smiling. There is a successor!

"Please look here, everyone." I took the old straw hat off my head and held it in my hand, pointing to a black net on the top of the greenhouse. "This is the sunshade net in the greenhouse, similar to our sun hat. It can keep the strong sunlight out of the greenhouse, but it is more effective. It can also ensure that the temperature in the greenhouse is about 30 C, so that the seedlings will not catch cold. " After listening to my story, everyone was amused by me and laughed. A smart card found the "water drop" on the top of the seedling and shouted, "Uncle, look!" "Little observer, this is the breath of seedlings. Explain that the growth is good. "

After seeing off the little guest, the staff and I went back to work, "Hey! Lao Wang, that seedling is still yellow! Turn it over quickly! " Lao Wang walked to the iron shelf and skillfully turned the wheels with thick wrists on the side. The iron frame rotates slowly, and the seedlings on the back immediately face the sun. In a few days, they can "turn yellow and green".

Looking at these stout seedlings, I fell into meditation: when can I move the "greenhouse" to the rice field?

Fourth grade scientific composition 3 20xx 165438+ 10/6 Our science teacher asked us to bring our own solar water heater. At noon, we started a "water heater performance competition".

First, Zhu Ying and I played "Slim Little Black Box". Yeah, neither fat nor black. The next contestants are Zhu and Jin's "Small Magnifier with Thick Waist and Face". This box is very big, but only a rectangular hole is cut and there is a magnifying glass on it.

……

At the beginning of the game, everyone rushed to the drinking area to pour cold water. "one! Two! Three! Go! " The competition began, and rows of solar water heaters were neatly placed in sunny places. The owners of the "contestants" can't wait, so they all go to eat.

After lunch, everyone ran to their own solar water heaters, opened the lid and felt if the bottles were hot. People without water heaters are like a curious audience. Look at the progress of the "player".

Finally, the owner of each "player" became a kind person and poured boiling water into everyone's mouth. Everyone who drank it said it was warm and good.

Shen Jiahao, who drank the water from my water heater, said, "Oh! It's really hot! " Xu Rui also drank, but said nothing. We all drank hot water, hot! There is no winner in this game, everyone is a winner.

The scientific works competition was a great success, and everyone was very happy.

On Sunday, I participated in the innovative modeling activity of 3D printing "Scientific Salad Sauce".

As soon as he entered the door to sign, a salesperson pointed to a row of things that looked a bit like piggy banks and said, "Scan the QR code and send one." Seeing a lot of people taking it, I asked my mother to sweep it, too.

The teacher who taught us this time is the manager of my shop. He asked us if coins would disappear, and asked us to design a coin classifier. Some people will answer, because now they all use Alipay to pay, and not much cash is used; Some brains are wide open, saying that the refraction of light can make coins disappear; Some people say no because our children need change. Finally, the teacher commented that coins will not disappear at present. They are stronger than paper money and are not easy to be damaged, so there is a great market demand.

The most wonderful thing is to draw a 3D model in the computer room. Click "Doctor's Hat", 1 change 2, click the ellipse, and change 25 to 26. Draw a circle on the middle graph, with 100* 100 change 150 in the upper right corner. The teacher patiently taught me that I want to be a hermit crab, and others think I am a crab. Finally, you can print your own works in 3D mode.

A happy activity really makes people reluctant to leave.

There was a long-awaited science experiment class on Tuesday, and I excitedly brought a bright mirror according to the teacher's request.

The class began, and I couldn't wait to take out the mirror. The teacher gave each science group a thermometer, and asked us to reflect the sunlight on the bulb of the thermometer with a mirror, and then record it when it stopped changing.

When we came to the corridor, Lu Zhirou bent down and carefully fixed the thermometer on a shady wall. After many twists and turns, I finally succeeded in reflecting sunlight accurately to the bulb of the thermometer with a mirror. It looks easy, but it is not easy to do. I haven't moved in the mirror for five or six minutes!

Hey, why is there light and shadow here? Moreover, this light and shadow is still flickering and running around. Look! Still on the bubble of the thermometer! I looked for the "murderer" while holding the mirror carefully, haha! It turns out that the boys in our group are naughty again. They looked at each other in the mirror and looked at us eagerly, which made them feel very interested. I advised them to stop playing, but they were more enthusiastic. I started playing as soon as I finished reciting it. Because of their influence, the liquid injection amount of thermometer fluctuates up and down. It seems that the experiment can't be done without them. So, I kindly negotiated with them. In fact, they don't want to make trouble, but they can't resist the temptation of "toys". I will keep their mirrors for the time being. Without their toys, they are no longer naughty. Finally, our experiment finally succeeded.

If only those naughty boys would stop being naughty! Our group will definitely be better! Experiments will be more interesting!

Like most people, I used to think that science is so far away from us that only a few top people can get in touch with these profound things that affect human progress. Today, I became a so-called "minority" and walked into Wenzhou Science and Technology Museum to have a close look at the science lurking around us.

After queuing into the gate, everything in front of you suddenly became clear. The blue wall, the white floor, and all kinds of novel things rushed into my eyes, which made me dazzled.

With the rapid footsteps, we came to a blue hall, where there are many new things I have never heard of, such as the giant Rubik's Cube, the sound tube, the cloud ring … and the two most difficult games in history: Brahma Tower and Huarong Road.

But comparatively speaking, what impressed me the most was the tilting cabin and the camera cabin. Let me introduce the inclined cabin first. When you walk into the cabin, you will feel dizzy and out of control. Why is this? The teacher gave the answer. It turns out that the sense of balance of the human body comes from an organ called vestibule in the earlobe of the human body. Vestibule can adjust the sense of balance of human body. The vestibule can feel the balance of the human body (vertical or inclined), feel the height of the ground with vision, and send out nerve information through muscles. The brain synthesizes the above information to make judgments, and then sends instructions to bones, muscles and related organs.

When someone enters an inclined cabin, because the inclination angle of the ground is 18 degrees, the information reflected by the vestibule is that you are standing on an inclined plane, but the wall you see is vertical. The visual information produced by experience mistakenly makes people think that they are standing on a horizontal floor, and the contradictory information is intertwined, which makes the human brain unable to issue correct instructions. Therefore, we will find it difficult to walk.

Let's go to the photo studio. In the dark room, the teacher pressed the flash and left my hand ten seconds later. My shadow stayed on the wall. Why is this? It turns out that the photo screen is coated with a layer of fluorescent material, which can be excited by light for a few seconds after being irradiated by light source (commonly known as afterglow phenomenon). When the graphic blocks the light source, the fluorescent substance on the screen does not receive the light energy of illumination, and the graphic remains on the screen because it does not emit light. Magical science, after close to understanding, is not out of reach.

Go up the stairs and come to the popular science show theater looking for Bernoulli. When everyone was seated, the activity began. Miss Xiaohua asked the assistant teacher to put the props on the table one by one, including water, straws and hair dryers. Teacher Xiaohua put the straw into the water, pointed the blower at the other side of the straw and turned on the blower. At this time, the whole platform was quiet. In an instant, artificial rainfall began to fall in the air, and the teacher explained: "The place with high air pressure will flow to the place with low air pressure. Where the air velocity is fast, the air pressure is low, which is the Bernoulli principle. "

Next, they did another experiment to further verify this principle. I saw Mr. Che holding props, a 13 kg iron ball, wooden mats, pipes, covers, exhaust fans, etc. At the beginning of the experiment, Miss Xiaohua put the iron ball on the wooden mat, covered the big pipe, covered the lid, and aimed the exhaust fan at a hole in the lid. A 13 kg iron ball was sucked up. "This is the practical application of Bernoulli's principle in real life. Can the students understand it? " Teacher Xiaohua said kindly to us.

Close contact with science is over, but my mind is still playing what I saw and heard in the museum, and I can't get rid of it for a long time. The beauty of science is everywhere. Without access to it, human civilization and progress will be difficult to advance. The exploration of science and technology is endless. Science, I'm coming.

Today, I saw the strange thing that eggs can "swim" from the book Science Explorer. I also drew lessons from the introduction in the book and made a scientific experiment.

First, put an egg in a bigger container. Then, fill the container with vinegar or hydrochloric acid and soak the whole egg in it. There is no hydrochloric acid at home, so we have to use vinegar. Then let's see what happens.

I watched ... the egg first sank below, and some small bubbles appeared on the eggshell, and then slowly swam up with the small bubbles. I watched for a long time, and nothing else happened. What happened? The book says that eggs will sink, and I hope they will sink again, but they just won't sink.

So I turned on the computer to see if anyone else was doing this experimental video online. I saw them put eggs in hydrochloric acid. After the egg is in hydrochloric acid, it will produce more bubbles, and "Gollum" will float for a while, somersault on the liquid surface and sink again. Later, it floated up again ... and so on, until there was not much foam.

The experiment in the video is much better than mine. They experimented with hydrochloric acid. Hydrochloric acid is transparent and the experimental phenomenon is very clear. The vinegar I used is opaque and I can't see it clearly. Doing a good job in scientific experiments is really particular. In addition, I also found that hydrochloric acid may make eggs swim better than vinegar, because hydrochloric acid produces more bubbles.

After a while, I took the eggs out of the container and found that the hard-shell eggs were only covered with a soft "skin".

It turns out that eggshells are composed of inorganic salts and organic matter, and all inorganic salts are reacted by vinegar, leaving only a thin layer of organic matter. I asked my father, are these organic substances edible? Dad said, "Silly son, how can you eat so little organic matter?" I said, "Animals eat organic matter, and a layer of skin is also organic matter!" " As he spoke, he tore off a little skin and sent it to his mouth. Dad saw it. Stop it. I accidentally knocked over the container and spilled vinegar all over the floor. Ha ha!

Science is really amazing! Through this experiment, I learned some scientific principles. If we explore hard, we will find more secrets.

According to my mother, a long time ago, there were no lights, telephones, cars and washing machines in the world ... I think people at that time should be so tired, bored and inconvenient! Thanks to scientists, their inventions make our world so beautiful. Therefore, I also want to be a scientist and invent more useful things for people.

Nowadays, because of environmental pollution and people's life pressure, diseases are getting younger and younger, and many people get incurable diseases at a young age and die young. White-haired people send black-haired people, which is the sadness and pain of many parents. In addition, there are so many infectious diseases, such as SARS, hand-foot-mouth disease, type A H 1N 1 and so on. This makes many people "talk about illness and change color." If I were a scientist, I would invent a medicine, which will make people recover immediately after taking it, just as good as a cold and fever now. Besides, this medicine is very cheap and everyone can afford it.

Our parents often worry about our clothes. When the seasons change and we grow taller, we have to buy new clothes. The water is so cold in winter, but we often get dirty for fun, which makes our parents wash our clothes and our hands freeze like carrots. If I were a scientist, I would invent such a kind of clothes: it will change color and thickness with the change of seasons, and even change a style once a week, so that you won't get tired of wearing it. More importantly, it will never be dirty, lest our parents wash our clothes again.

If I were a scientist, I would invent many things that are beneficial to mankind. Of course, being a scientist is not that easy. So I will study hard and strive to realize my ideal as soon as possible.