Composition for the fourth grade of the experiment 1: "Under the banyan tree by the pond, cicadas crow in the summer sound." Whenever I hear "Childhood" sung by Tayu Lo, I can't help thinking of my own childhood. Childhood is like a five-flavor bottle. There are five flavors in the bottle: sour, sweet, bitter, spicy and salty, and each flavor has its own story. I remember it happened at the age of 10. ...
One sunny afternoon, I did an experiment at home. This is an experiment about candles. First light a candle on the top, then take out an empty mineral water bottle and a washbasin, and put red water in the washbasin, and you can clearly see the results of the experiment. I gently put the candle with a small fire into the empty mineral water bottle, with the lighted end facing the direction of drinking water and the two bottoms facing each other. Then I pressed the bottle mouth of mineral water in the center of the washbasin and kept it in its original position. I discovered a secret.
Gradually, there is less and less water in the washbasin until there is no water. It turned out that so much water was "drunk" by candles, and the water gradually flowed into its "body" and became bacteria. Of course, it's just my whimsy. But why can candles "drink" so much water? This makes me very confused. I ran to ask my parents, but they didn't give me a satisfactory answer.
I can't wait to go to the computer and find out the information that the candle "drinks" water. It turns out that the gas generated by candle burning and the heating of the surrounding air make the gas expand and the density decrease. At this time, the candle is covered, and the candle is extinguished due to lack of oxygen. When the candle goes out, as the air temperature in the cup drops, the density increases and the volume decreases, while the external air pressure remains unchanged, and water pressure is put into the cup.
There are many mysteries in life waiting for us to discover. We should observe them with beautiful eyes.
At the weekend, I watched a magic show. I fill a cup with water, cover the mouth of the cup with paper, and then turn the cup upside down so that the water won't flow out. I think it is amazing. How can a thin piece of paper hold such heavy water?
I asked dad, and he said he didn't know what was going on. Tell me to check online myself. It turns out that whether the cover falls off depends on the force on the cover. The atmospheric pressure under the lid holds the lid, while the gravity of the water above the lid and the atmospheric pressure in the cup press the lid down. At this time, the upward atmospheric pressure on the paper covered by the cup mouth is greater than the gravity of the water in the cup, so the water will not flow out.
I decided to experience it myself. First, I found a transparent glass cup and a piece of A4 white paper, came to the balcony, filled the cup with water, and then closed the lid of the cup with a piece of paper. Finally, I held the paper in my hand and turned the cup upside down. As soon as I let go, I found that the paper didn't fall and the water wouldn't flow out. I was very surprised.
"The power of a piece of paper is really great! Try it with half a glass of water! " I said to my father. I filled half a glass of water, half a glass of water and half a glass of water in the same way. After the cup was turned upside down, the water didn't actually flow down. I leaned the cup again, and the water in the cup was out of balance, and the water flowed down from the other end of the cup mouth.
I looked it up on the Internet and said that if a glass is filled with half a glass of water, the water will flow out, but the paper can't hold the water in the glass. Experiments show that the atmospheric pressure in the cup is lower than that outside the cup, and the atmospheric pressure outside the cup holds the paper, so that the water in the cup will not flow out.
Today is the open day of experimental middle school, which is open to the citizens of the whole city and the majority of primary school students. My father and I arrived at the experimental middle school early in the morning.
Walking into the gate of the experimental middle school is the big playground of the school. The 400-meter red rubber track looks professional. There are three basketball courts in the middle of the runway. Many students are running and playing basketball on the playground. The activity space is really spacious! Next to the playground, there are two L-shaped six-story teaching buildings. Walking into the first floor of the teaching building, there is an auditorium that can accommodate nearly 600 people. Starting from the second floor, there are classrooms and teachers' offices for students from grade one to grade three. There is a multi-function hall on the sixth floor of the teaching building, where everyone can get together to watch the school propaganda film. According to reports, experimental middle school is a key junior high school. Due to first-class teachers, strict teaching and complete teaching facilities, more than 95% of students are admitted to key high schools every year. Being admitted to study here is equivalent to entering a key high school! Finally, we also visited the roof of the teaching building, where there is a carefully cultivated botanical garden, and the lush green plants are very attractive. ...
The experimental middle school has a good environment, high teaching quality and strong learning atmosphere, which is the goal of primary school students in the city to study hard. I also hope that through my own efforts, I can be admitted to this key junior high school!
Friend, have you ever done the experiment of eating eggs in a bottle?
Today, in Teacher Deng's happy composition class, Miss Wang gave us an article. Do you want to do it? Let me introduce you!
In the composition class, Teacher Wang asked, "Do you know that bottles can eat eggs?" Some students say yes, some students say no, and some students say no! Teacher Wang said, "Now let's do an experiment!" So, Miss Wang took out an egg, a bottle, a lighter and a piece of paper.
The experiment began, and I thought to myself: What did the teacher do? I saw Mr. Wang peeling off the eggs, and the white and tender eggs made the students drool.
At this moment, I seem to hear the bottle saying, "Sister Egg, do you believe I can swallow you in one gulp?"
Sister Egg smiled and said, "Brother Bottle, you have such a small mouth, how can you swallow my fat body in vain!" " "I think you are daydreaming!
The bottle proudly said, "Hum, just wait, I'll eat you right away!" " "
I saw Mr. Wang holding a piece of paper, lighting it with a lighter, putting it in the bottle, and then quickly putting the egg on the bottle mouth. Bang, half an egg fell into the bottle.
At this time, the bottle proudly said, "Sister Egg, you give up!" " ! Hahaha! "
"Why is this?" Teacher Wang asked. Everyone couldn't think of it, so Mr. Wang told everyone: "Because the fire burns in the bottle, the gas in the bottle is reduced, the pressure is reduced, the air pressure outside is high, and the pressure presses the eggs into the bottle." "
This experiment is so interesting! It can not only enrich our after-school life, but also make me understand a scientific truth!
In the class of science and technology team meeting, the teacher asked a question: eating soft steamed bread is light and tasteless at first, and slowly, it begins to become a little sweet. What happened? So, we prepared iodine and some vegetables and steamed bread according to the teacher's requirements, and started the experiment at home. It is said that you can get results with these simple things.
The experiment began. I couldn't wait to put the prepared materials on the table one by one and began to do as the teacher said: first, I chose a potato and cut it into pieces; He took another corn, cut off many corn grains, and had the main tool-steamed bread. Curiosity drives my hand. I sprinkled iodine drop by drop on potatoes, corn and steamed bread. What will happen? The iodine on potatoes and corn soon changed from black to pure blue, while the steamed bread changed from deep red to black and then to purple after being coated with iodine.
It's amazing, but the question appears like a swarm of bees: why does iodine change color? It turns out that potatoes, corn and steamed bread all contain a high molecular substance called starch. Starch and iodine form an inclusion compound, which changes the light absorption and color. However, what does this have to do with the sweetness of steamed bread? This is because our saliva contains an acidic substance called digestive enzyme, which will turn into a sugar when it meets starch, which is why we eat steamed bread more and more sweetly.
This is an interesting iodine starch experiment.
Nature is a treasure house of knowledge. As long as you are willing to explore and think seriously, you can always get a lot of inspiration from it.
As soon as I walked into the classroom today, I saw an insulated water cup and a plastic water cup and thought, what are you doing today? The teacher came and solved the mystery in our hearts. The teacher said, "Let's do a little experiment today." We all craned our necks to see what tricks the teacher would play. The teacher first wrote two words "lose weight" on the blackboard and asked the fattest classmate in the class: "Do you want to lose weight?" Xiao Pang said he wanted to go. I thought, what does this have to do with the experiment?
After a while, the teacher said that whether you believe it or not, this bottle can make him lose weight without external help. Some people are dubious, some people don't believe it, and some people believe what the teacher said. The experiment has begun! The teacher carefully poured the hot water from the thermos into the plastic bottle first, and only heard the sound of running water, which soon filled it up and hot air came out from time to time. Then the teacher poured hot water back into the thermos, and a miracle happened! The bottle slowly became a slim girl like a big fat girl. Just as everyone was wondering, the teacher explained the principle to everyone one by one. The teacher said, "The hot water heats the air in the bottle, which makes the air volume expand. When the hot water is poured out from the heat source, the air temperature drops and the volume becomes smaller. If the bottle cap cannot be tightened to replenish the air, the plastic bottle will collapse."
There is so much learning in life! As long as we carefully observe and explore, there will be more discoveries!
One day, I really had nothing to do, so I found a bag of salt, an egg and a basin and began to do experiments.
As soon as I got started, I put a pot of water, put the eggs in, found a spoon, poured the salt into the bowl and put it into the water one by one.
When I put the first spoonful of salt, the eggs didn't change. I thought, man, why don't you respond? That sucks! Forget it, put another spoonful ... so, I put a second spoonful of salt, but the eggs haven't changed. I thought: If you stir it by hand, maybe the egg will react. So I began to stir it in the water with my hands. After 5 minutes, my hands were sore, but the egg still didn't move. So I began to put the third spoonful of salt. This time I thought to myself, have you changed now? But the egg man still did not move. "Egg man, you don't give force, you don't give force, but you have to give a face. That's all. Add another spoonful of salt later. " I said helplessly. I put another spoonful. () As I put it, I said, "Last spoonful, last spoonful ... If you don't move this brother, I won't wait on you. Add more salt, the fifth world war will start, and I will be crushed by the jack. " When the fifth spoonful of salt was finished, I closed my eyes, folded my hands and prayed in my heart: "Bodhisattva, show your spirits and let the eggs float." After a while, I slowly opened my eyes and found that the eggs really floated as I hoped. I couldn't help but say loudly, "Brother Egg, you really' hid half her face behind her guitar from us, but we shouted a thousand times before she came to us'."
The experiment was successful, but why did the egg float? So, I went to the Internet to find out the reason: the original salt water is heavier than water and has greater buoyancy, so eggs will float in salt water.
Through this experiment, I understand that science is around. As long as we observe carefully, think seriously and do it seriously, we will find many mysteries.
The fourth grade composition 8 of the experiment began, so we ran into the laboratory quickly. This class is a long-awaited science experiment class. I know the teacher will take us to do the experiment in person.
The teacher strode into the laboratory with experimental equipment. After putting away the experimental equipment, she said happily, "Students, today we are going to do an experiment about what factors are related to the magnetic force of electromagnets. Please pay attention. " Our interest was raised at once, and we chatted quietly. We are all curious. Then the teacher said, "The magnitude of magnetic force is related to the number of turns of the wire. The more turns the wire makes, the stronger the magnetic force is, and the less turns the wire makes, the weaker the magnetic force is. We need to prove it now to see if it is true? " Then the teacher handed out experimental equipment, a one-meter-long wire, a fifth battery, a big nail and a pile of paper clips. I was very excited and soon began to do experiments with my teacher.
I first wound the wire around the nail for 20 times, connected to the power supply to suck the paper clips, and many paper clips were sucked up; I only circled my nails six more times, and I only sucked a few paper clips on my nails. Through this experiment, it is proved that the magnetic force of electromagnet is related to the number of turns of wire. The more wire turns, the stronger the magnetic force. On the contrary, the less the number of wire turns, the weaker the magnetic force. The teacher also told us that scientists invented the generator by using the principle of electromagnetic force, and so on. The teacher also said that science is around us. As long as we find it with our heart and feel it with our heart, we will understand the scientific knowledge that exists in our lives. Scientists have also made great inventions through these small experiments.
Although this experiment is very simple, I got happiness from it, experienced the joy of success and gained knowledge. Scientific experiments can not only develop our intelligence, but also exercise our hands-on motivation. I hope there will be more such scientific experiments for us to do in the future.
Composition 9 in the fourth grade of the experiment "Can the explosion put out the fire?" After listening to my cousin's words, I think this is simply whimsical. The power of fire is so great that explosion can only increase the power of fire. How can we put it out? But my cousin was very confident and invited me to watch a live performance.
I followed him to the yard in disbelief. I saw a pile of old newspapers scattered on the ground, and there was a small fire pit next to it. Cousin took out another box of small firecrackers and began to do experiments.
Cousin stuffed some newspapers into the fire pit and lit it. Suddenly, a flame came up. No, he jumped out of the fire. Seeing that the fire was getting fiercer and fiercer, I couldn't help turning my head to look at my cousin, but he still stood by confidently with a smug smile on his face. Can throwing firecrackers into a fire really make a fire? Maybe blow up the yard. It's possible.
The fire burned quickly, and soon many newspapers caught fire. With the fire, smoke came out. At this time, my cousin took out a small firecracker and lit it, then threw it directly into the fire pit. It's going to explode! I quickly closed my eyes and covered my ears. A loud noise still penetrated the eardrum. I looked into the fire pit, and to my great surprise, everything in the fire pit went out. My cousin proudly said to me, "You have to believe it this time!"
What's going on here? Under my repeated pressure, my cousin told me that air is needed for the burning of fire and the explosion of small firecrackers. At the moment when the small firecrackers explode, the surrounding air is absorbed by them, and the fire can only be extinguished by itself without air. Oh! I see. I see! It's really "it's better to study for ten years than to listen to you"!
I accidentally read an article on my mobile phone today, saying that chewing gum can open coconuts, but how can chewing gum open coconuts? It was strange, so I decided to chew gum and do an experiment.
The experiment is ready to start. There are five coconuts and ten pieces of gum. I chewed a piece of gum and shaped it into a cone. The desktop was erected on the table. I picked up the coconut and found its cover door-the place where there are three soft eyes at one end of the coconut is its cover door. I aimed the coconut door at the tip of the chewing gum and hit it hard. I thought a miracle would happen. Unexpectedly, the chewing gum actually stuck to it, and the chewing gum failed.
So I made the dry chewing gum into a cone, which was a bit difficult to make. I spent a little more time. After eating, I put it on the table with the tip of my pen facing up. Then I picked up the coconut and smashed the blindfold at the tip of the gum. There is no juice flowing out. I thought it was a failure, but I didn't expect to hit a small hole and gave me great encouragement. I made another cone-shaped chewing gum. This time, I put the top up on the ground, picked up another coconut, carefully pointed its lid at the chewing gum, and smashed it down steadily and accurately. It broke smoothly!
But I still wonder why gum can open coconuts. I looked it up online. It turns out that chewing gum is a non-Newtonian fluid. The non-Newtonian fluid has a characteristic that it will give you as much force as you give it.
The little experiment I did today not only succeeded, but also taught me a new knowledge. There are so many interesting and wonderful things!
There are many TV programs I like to watch, but my favorite TV is open sesame, because it often shows us some experiments and tells us scientific truth. I imitate them, among which I like to do the experiment of "friction electrification" best.
I prepared a piece of paper first, cut it into many small pieces and put it on the table. Then bring a plastic pen and gently rub it back and forth on your hair. Put the pen in a piece of paper. These pieces of paper are attached to plastic pens. I shook it gently, and the paper seemed to be dancing. I think it is amazing. After repeated experiments, I still feel unsatisfied. "I have done so many experiments. What is its principle? " I thought to myself. It's dusk, but I still don't know how it works.
In the evening, I asked my mother for advice and asked why. My mother said to me, "The kind of experiment you just mentioned is because the plastic pen rubs the hair to generate static electricity and absorbs the small pieces of paper." For example, when the weather is dry, when you comb your hair or take off your sweater, you will also generate static electricity, hear crackles and even see the light of discharge. "After listening to my mother, I finally know the final answer of this little experiment.
By doing this experiment with my own hands, I understand that many natural phenomena in our real life contain a scientific truth. As long as we are good at observation and diligent in thinking, we will certainly know the mystery.
The composition of the fourth grade in the experiment 12. Today, I finished all my homework. Then I turned over the TV channel n times, but I didn't find a program that was more appetizing. So, I picked up a book and read it with relish. Among them, there is an experiment of "eggs floating", which interests me very much. So, I decided to try it myself and see if I can succeed.
I first found the experimental materials, a cup, an egg, a bag of salt, a chopstick and a spoon. The experiment began. I first poured more than half of the water into the cup and carefully put the eggs into the water. The egg sank to the bottom of the cup like a stone. Then, I scooped a few spoonfuls of salt into the water and stirred it with chopsticks. The egg dances like a little girl and swings from side to side, but it can't float. I wonder if there is too little salt. So, I added another spoonful, and the egg still didn't float. At this time, I was impatient. In a rage, I put 4 spoonfuls of salt and saw many small bubbles around the eggshell, and the bubbles were getting bigger and bigger. After a while, the egg slowly shook its fat body and gradually showed its face, like a little doll swimming. Wow, I made it!
I cheered and my mother asked me why. I said, "the buoyancy of clear water is small, so the egg sank;" When salt water is buoyant, eggs will float. "Through this experiment, I know that wisdom is acquired unconsciously. I will read more books, do more experiments and learn more knowledge in the future.
I'm a little bored this morning. I want to do experiments to relieve boredom. I asked my father, "Dad, what experiment shall I do?" Dad scratched his head, his eyes lit up and said, "You will know later!" " "
So I stared at my father. He took out a bottle with a little water, unscrewed the cap and asked me, "I'll open the cap and turn the bottle." Guess what the water in the bottle is like? " I said without scruple, "Come out!" Dad smiled, then immediately turned the bottle from bottom to top, without dropping a drop of water. I was so surprised that my mouth grew up and said, "You. Do it again. " Dad turned the bottle around again, and the water stuck like glue without leaking at all. I think the two monks are very confused. So I asked my father curiously, "What the hell is going on?" Dad bought a lock: "Guess?" I kept asking him to tell me. Finally, he finally told me the answer: "This is because gravity is downward, so water will not drip out, but if the speed slows down, water will leak out." I nodded, as if I understood.
This is really an interesting experiment! From this experiment, I learned another scientific truth. I will do more experiments and learn more scientific truth in the future.
On Monday morning, I experimented with the fourth grade composition 14, and said, "Come on!" Or "failed again"! What's going on here? Let's have a look.
So we're going to do experiments! The teacher asked a question: Can a piece of paper be folded in half nine times? Some students said yes, some students said no, and some students said they were not sure, so the teacher asked us to do the experiment.
The first experiment began, the material-A4 paper. I am responsible for origami. I think I can fold it nine times. The first time I folded it, I didn't find it difficult. I started to struggle for the fourth time. By the sixth time, I was out of breath, so by the seventh time, I couldn't fold it in half. I was ashamed to think that I could fold it nine times before. I glanced at the group of people next to me and found that my classmates were biting the paper with their teeth and trying to fold it in half. This scene made me laugh.
The second experiment started, and the material was A3 paper. This kind of paper is much larger than A4 paper. The teacher asked a classmate to try first, but he still failed. The students are very disappointed. At this time, Xiao Ming volunteered: "I'll do it!" The students' eyes lit up again, and the result ended in failure.
This time, we will do the third experiment with tissue paper. Divided into three layers, one layer succeeds and the third layer fails.
This experiment made me understand that the number of times a piece of paper is folded in half depends on its thickness and texture, and also made me understand that it is necessary to make bold guesses and attempts.
Do you know how many times a piece of paper can be folded at most? Have you thought about this question? I found the answer in an interesting composition class.
It was a composition class, and the teacher gave each of us a piece of A4 paper. See if it can be folded more than nine times at most. I think it is very easy to confidently pick up A4 paper and fold it.
It's too simple. I folded it twice. It's a piece of cake. I continued to fold, and by the fourth time, the paper had shrunk to the size of an egg, and the paper had hardened, but it could still be folded. I'll keep folding. It's already the seventh discount, and there's still 20% left. But this paper seems to be against me. I gritted my teeth and tried my best to fold it, but I couldn't. Later, I simply punched it with my fist, and it took several times to hit the paper, but it was no longer a "pattern", so I think the following is unbreakable. Finally, I realized that a piece of paper can be folded up to seven times.
After this experiment, I have benefited a lot. What I understand is not only the answer to the experiment, but also the need for continuous exploration and discovery in life, which is meaningful.
Teacher's comment: Because the process description is very vivid and accurate, the interest of the experimental process is unforgettable.