Why is a bottle full of water not easy to break? There are two identical glass bottles, one is empty, the other is full of water, and at the same time it falls to the ground from the same height. Which bottle breaks easily? Generally speaking, heavy bottles break easily.
But when the bottle is filled with water, the water in the bottle has another function, which can reduce the deformation of the bottle and make it difficult to break. Most of the broken glass bottles are caused by deformation.
When the empty bottle falls to the ground, the pressure is constantly exerted on the bottle, and the bottle is deformed from the outside to the inside and finally breaks. The bottle is full of water. Because water is incompressible, the deformation is reduced and the bottle is not easy to break.
The bottle is filled with water, and then the cap is tightened, so it is more difficult to break. Have we inhaled the soda? We suck soda through a straw, always thinking that it is our mouth that sucks soda up.
Actually, it's not. It only sucks the air in the straw. As for soda, it is the atmosphere that presses it into the mouth. It turns out that after the air in the straw is sucked away, the soda in the tube is reduced by the air pressure, while the soda in the bottle (outside the straw) is at atmospheric pressure. These two pressures are not equal. If the atmospheric pressure is higher, soda will be pressed into your mouth.
If the soda bottle is covered with a cork and a glass tube is inserted in the cork, you can suck soda from the glass tube once or twice at most, and you will never get soda from the bottle again. The reason is also very simple, because the atmosphere outside the bottle can't enter the soda bottle, and the atmosphere can't press the soda into the mouth.
Can I still drink soda without unplugging the cork? Although it can't be sucked up, can it be blown up? Blowing air into the glass tube is one way. Blowing increases the gas in the bottle and increases the gas pressure in the bottle.
When the pressure of the gas in the bottle increases, the soda will be squeezed out of the glass tube. At this time, as long as the mouth does not leave the glass tube, soda can be drunk. The more you blow into the bottle, the more the pressure increases, and you can drink soda smoothly.
After drinking some soda, the volume of gas in the bottle becomes larger and the pressure decreases, so you can't drink soda. Blow again, and you can continue to drink soda.
Famous saying: 1 Only by obeying nature can we overcome nature. -Darwin 2. Nature is a kind mother and a cruel butcher. -Hugo 3. People often treat the environment around them as a free commodity, spoil it at will and don't know how to cherish it. -Gan Haman 4. The earth has given all people the essence of material things, and in the end, what it gets in return from people is the rubbish of these things. -Whitman 5. Not only can we not force nature, but we must obey it. -Escuman 6. Because of our invasion of nature, we have destroyed the beauty of natural landscape, natural dynamic beauty and natural beauty. -Norman Cousins 7. If you want to live safely, you must have five things: first, purify the air; Second, we must clarify drinking water; Third, we should recycle ditches; Fourth, clean the house; Fifth, there should be plenty of sunshine. Florence nightingale.
2. Fifty popular science speeches
He is of medium height, oval face, black hair and big sparkling eyes. He looks smart and capable. He is the teacher Liu who helped me write my composition in the Bowen Education Training Class.
Because the teachers who teach our class at school are all female teachers, when I first met Mr. Liu, I had a kind of alienation and prejudice against male teachers, thinking that male teachers were not as good as female teachers. Male teachers are fierce, not as gentle and amiable as female teachers. Therefore, many times I don't want to take a composition class. Even sitting in the classroom, I feel uncomfortable and don't listen carefully.
One day, Mr. Liu was giving a lecture, and I couldn't understand it. I raised my hand to ask questions. Teacher Liu was not only not angry, but also patiently explained it to me in a gentle tone. I am very touched. Well, not all male teachers are so grumpy. I feel that the previous idea is wrong, and things are not what I imagined. From then on, I listened carefully.
As time goes on, I know Miss Liu better. But I also sincerely thank him in my heart. One day, I was concentrating on my homework in class. Who knows, my deskmate drew a turtle on one of my test papers. I burst into tears when I saw it, and tears fell like broken beads. Teacher Liu came over and asked me why I was crying. After he understood the reason, he severely criticized my deskmate. Then, he comforted me with a kind voice: "My child is good, don't cry, it doesn't matter, I have criticized him ..." My sobs gradually died down. I deeply felt Mr. Liu's concern for the students.
During the short study, Mr. Liu and we gradually established a deep relationship between teachers and students. On the day of the end of the training class, he came into the classroom with a smile, played a game with us first, and then began to give lectures. The students had a good time and listened with relish. Teacher Liu taught us the knowledge and writing methods he learned without reservation.
Now Mr. Liu has been meeting us for almost a month, and I really hope that Mr. Liu will give us another composition class. I really hope that the day when Teacher Liu will help us write our composition will come soon.
3. The scientific speech is about 100 words.
Speech:>
My most revered celebrity-Madame Curie
Some people worship celebrities in order to catch up with fashion, and this blind worship will lead people astray. Some people respect celebrities, regard their respected celebrities as their role models, and motivate themselves to make contributions to those who like them. Confucius said "See Si Qi", and people often say that "the power of an example is infinite", so most of these people have succeeded. Everyone has his favorite celebrity, whether it is worship or reverence. Besides, I admire Madame Curie.
For thousands of years, beauty has always been a woman's highest honor and biggest capital. As long as you are lucky enough to get this, don't ask the rest. Madame Curie has beautiful capital, but she is useless, and it is from this point that she conquered herself. In order to do scientific research, she is willing to let acid and alkali gnaw at her soft hands and let the choking smoke wrinkle her beautiful forehead.
In order to extract pure radium, the Curies got a ton of industrial waste residue which may contain radium. They set up a pot in the yard, melted it one by one, and then sent it to the laboratory for dissolution and precipitation analysis. The so-called laboratory is an abandoned shed, and the body is used for autopsy. Mary stirred the slag in the pot in the smoky fire all day, leaving acid and alkali burns on her skirt and hands. However, her efforts were not in vain. Finally, she discovered the natural radioactive element-radium.
She could have applied for a patent immediately after discovering radium, and thus gained a large fortune. However, instead of doing so, she did not hesitate to publicize the purification method of radium. Later, Madame Curie was unable to engage in scientific research because she had no funds to buy 1 gram radium. Finally, a well-known American female journalist launched a fund-raising campaign in the United States, raising the required $654.38 million+.
Madame Curie was the first woman to speak on the podium of the French Academy of Sciences.
I admire Madame Curie's personality. Madame Curie regarded fame and fortune as dirt. She won 10 awards, 16 medals and 107 honorary titles, especially two Nobel Prizes. She could have enjoyed herself in any prize or honor, but she gave the prizes for scientific research and war to France and gave those medals to her 6-year-old daughter as toys.
Madame Curie's noble character, like her outstanding scientific achievements, shines admirably in the history of human civilization. She is strong, pure-willed, and strict with herself, which makes me have to respect!
Thank you!
4. Scientific speech
Science is around me.
Confucius said, "Knowing is not as good as being kind, and being kind is not as good as being happy." Einstein once said, "Interest is the best teacher." I have a strong curiosity about science since I was a child. From primary school to junior high school, my science teacher took us step by step into the hall of science, so that we could have enough hands, words, mouths, brains and eyes. I like science more and more.
At present, most of the students in school are only children, and they are spoiled. I am a "son" at school, taking me as the center; At home, he is the "emperor" and does nothing. Lack of hands-on exercise and team spirit. Life knowledge and subject knowledge in daily life are extremely lacking. For example, about plant leaves. To my surprise, half the students can't tell the difference between wheat leaves, grass leaves and leek leaves.
In the study of science class, cooperative inquiry learning is very necessary. We work together, explore together, face difficulties together and enjoy the joy of success together. For example, in the class of "knowing the signs of fire", the teacher asked us to make a survey in groups to increase our common sense of life in the survey. Our group readily accepted this "task". First of all, we look for information and find out for ourselves. Then we asked some students about the signs of the fire we made. Through the investigation, we found that the current middle school students' understanding of fire safety signs is low. If they don't know the meaning of these signs when they grow up, it is very dangerous to go out in case of fire, but "in the direction of fire fighting equipment or alarm device"! We also thought that if these signs were listed and put out, but no one knew what they meant, it would be better to describe them in words, so we should learn to read now! In my opinion, it is also very important to teach students how to escape in case of fire. For example, public places are prone to fire, and students like us who lack escape methods are prone to danger. Our school once trained "how to retreat in case of fire", and also talked about "how to use portable fire extinguishers" and gave us drills. Through this simulated fire training, all the students in our class have a certain understanding of evacuation! It is not enough to just learn to retreat, so the teacher also told us some unexpected situations in the fire. For example, when the fire is huge, the fire in front is so big that you can't rush out directly. You will get wet and run outside with a quilt. Therefore, I think it is necessary to set these topics. And make a simulation, so that students will have a deeper memory. Through this survey, we have gained a lot. More clearly understand the importance of learning, loving and applying science. In the process of completing this task, my understanding of fire safety has increased a lot unconsciously. For example, I only know a little about fire safety signs, but I already know most of it after completing this task. At the same time, I also have a certain understanding of fire safety, and I also know how to protect and save myself in case of fire. This will be of great help to me in the future. In order to protect ourselves better, it is necessary for us to master these common sense. However, I don't think it's enough to know this. In every corner of the world, there are many fires every year, but don't people who die from fires know or understand this knowledge? That's not true. So I think the better way to protect ourselves is not to let fire enter our lives. Therefore, never play with fire. Pay attention to whether there are flammable materials in the surrounding environment before using fire. Therefore, in addition to mastering some fire prevention knowledge, we should also prevent the occurrence of fires, which is the best way for us to protect ourselves and others.
Science is all around us. As long as we always pay attention to, find problems and explore knowledge, we can experience our own ability, tap our own cultivation, improve our aesthetics and strong will, and form the quality of exploration and innovation in happy social practice activities. Li Ling, instructor of Zhan Xiaohui of Nanhua Middle School.
5. A 400-word composition about common sense of science and technology
Is the development of science and technology beneficial or harmful?
If you ask whether the development of science and technology is beneficial or harmful? Without a doubt, of course it is Lida! What is the explanation? No need to explain! China's 8,000-year history of civilization is irrefutable evidence. History has been changing and technology has been developing. Humans learn to use or cook food from primitive life, from relying on nature to thriving, from unarmed to metallurgical smelting. This is not progress, this is not development? If the disadvantages outweigh the advantages, then why do human beings choose progress in unison? Because only progress can make tomorrow better!
It is sad for a person not to make progress, a country is declining without progress, and a world is dark without progress. Only by continuous progress can human life be sublimated. God has given mankind a clever brain and a pair of hardworking hands. It is precisely because human beings choose to make continuous progress instead of enjoying success that they can stand at the top of today's food chain.
Life is so comfortable, life is so pleasant and life is so wonderful. Our average life expectancy is 30 years higher than that in ancient times, and we don't even have to go out to visit relatives and friends. Isn't this all the benefits of scientific development?
Therefore, science and technology change history, and we don't need to question whether the development of science and technology is beneficial or harmful, it is beneficial! Rita! Rita! You said that the development of science and technology brought air pollution, you said that the development of science and technology produced white garbage, and you said that the development of science and technology caused the warming of the temperature ... Everything can't be perfect, so you can conclude that the development of science and technology does more harm than good? Different times lead to different problems. Except air pollution, all provinces and cities have put forward prevention plans. White garbage, unified treatment; Automobile exhaust causes the temperature to warm, and scientists have also developed solar-powered cars. Look at now, solar water heaters, solar air conditioners, solar cells ... environmental protection and energy-saving solar energy are gradually entering thousands of households. Isn't this the development of science and technology?
Although there are disadvantages, it is irrelevant compared with the scientific and technological development concept of benefiting mankind and protecting home. As long as there are drawbacks, scientists will try to solve them. We can't stop eating because of choking, and the pace of scientific and technological development will not stop for a moment. There is nothing wrong with the development of science and technology, which is profitable! Just because science and technology have been advancing and science has been developing, cunning sophistry, generalization and unreasonable entanglement can't change this truth. It is true that technology has changed history. Without the development of science and technology, our life is unimaginable. Our days are dark. It was the development of science and technology that saved us, and it was science that saved us from the age of hydrothermal. We should respect him with awe. How can we say that the development of science and technology is full of drawbacks?
Science and technology change history, and knowledge changes destiny. We have entered the 2 1 century, an era full of high technology. Science has changed our lives, and science has changed our destiny. "Knowledge is power". Why can People's Republic of China (PRC) (PRC), a vast country with a population of 654.38+0.3 billion, stand tall in front of the world? Because our technology is constantly developing! Our technology is constantly improving!
The advantages of scientific and technological development outweigh the disadvantages, which is an eternal theme!
With the development of science and technology, human civilization has taken a big step forward, from the previous carriage to the car, from the previous oil lamp to the electric light. ...
6. Scientific speech
When you watch cute cartoons, play fascinating computer games, get on the express train and answer overseas calls, … do you feel the power of science? Science has not only changed the world, but also changed our lives. Science is all around us.
With the rapid development of science and technology, science not only serves the cutting-edge technology, but also penetrates into our daily life more and more, which requires us to love and learn science in our youth. Taking part in the science and technology "five small" competition and reading science and technology books have made me understand a lot of truth. Precision robots, cars without fuel, virtual football matches, high-tech information transmission, and so on, all vivid and interesting phenomena have aroused my desire to explore science. Each of us should learn science, spread civilization and create a new life while enjoying a new life. Nowadays, the upgrading of scientific and technological products is getting faster and faster, and video TV, computer surfing and pacemakers are nothing new. From the vacuum cleaner invented by 190 1 to artificial earth satellites and manned spacecraft, science and technology have shown great power in different fields. With the popularization of electronic industry and communication technology, and the wide application of nanotechnology and superconducting materials, bioengineered foods such as space green peppers and artificial steaks will appear on your table in the near future. Studying science and technology is not only to become a scientist and adapt to life, but more importantly, to become the master of the new century, to undertake the new century and to make contributions to national construction and human civilization.
Students, we are in the stage of growth and development. Let's learn science from an early age. We should strive to learn all kinds of cultural classes well, because this is the basis of all learning; At the same time, it is best to read more popular science books and newspapers suitable for our primary school students after class; We should also actively engage in various small scientific experiments, small productions and small scientific papers to cultivate interest in science. In this way, we can love science and have rich scientific knowledge.
There is no limit to human wisdom. No matter the Challenger explosion in the United States or the global computer virus upgrade, it will never stop the scientific and technological progress of mankind. "Knowledge is power", Bacon's well-known maxim inspired many people who are eager for knowledge. Now, let us also use it to motivate ourselves, be a new generation that loves science, shoulder the heavy responsibility of the new century, and write more brilliant poems for the future of our motherland!
Thank you all.
7. Primary school students' scientific and technological speeches should be about 300 words, not too profound.
Technology leads the future
Class 6 (1) of Chugou Primary School in Liulin County started school.
Think about how happy and happy we are as a new generation across the century!
After 30 years of reform and innovation, China has also made continuous progress and entered the era of science and technology.
In the past, in the classroom, teachers had to write lines of information on the blackboard. Now, technology is coming in this era. Dr von Neumann of Budapest University invented computers and multimedia? Has also entered our society, teachers do not have to write on the blackboard, can intuitively present knowledge points in a more diversified way in multimedia, convenient and fast.
In the past, communication was underdeveloped. In the 1970s, people used letters. Telegrams and telephones were used in the 1980s, and the Internet is used in modern households?
Nowadays, people need to carry plates in restaurants. If he is not careful, he will fall to the ground. It is conceivable that robots will replace people's careers in the future.
Innovate simple problems and use innovation in useful places, and you can create many new things, such as the invention of lasers, electric lights and computers.
However, due to human innovation in things, some things are harmful to the earth itself, and the increase of carbon dioxide has brought disadvantages to the environment. Therefore, while inventing many new things, human beings should also pay attention to protecting the environment, otherwise they will want to say "the end of the world in 2020" in the book in the near future, and this result is not what anyone wants.
We should raise the ideal sail high, inherit the struggle spirit of the older generation of revolutionaries, and let the motherland's economy take off towards prosperity and national rejuvenation.
8. Pupils' short story speech is about 100 words.
Science originates from life. Starting from life, life is the source of science.
Gong Gongxiang (Lu Ban) attaches great importance to the observation and study of objective things. Inspired by natural phenomena, he devoted himself to creating inventions. He cut his finger on the grass while climbing the mountain. He picked the grass and examined it carefully. He found small teeth on both sides of the grass, so he made a logging saw by imitating the grass. When he saw all kinds of birds flying freely in the sky, he cut them into kites with bamboo and wood and flew in the air with the help of the wind. It took a short time to start flying, but after repeated research and continuous improvement, it has been able to fly in the air for a long time.
King Hennon asked the goldsmith to make a pure gold crown for him. After it was done, the king suspected that the craftsman had mixed silver into the crown, but the crown was as heavy as the pure gold given to the goldsmith at the beginning. Did the craftsman play tricks? The problem of trying to test the authenticity without destroying the crown not only stumped the king, but also made the ministers look at each other. Later, the king gave it to Archimedes. Archimedes thought hard about many methods, but all failed. One day, he went to the bathhouse to take a bath. Sitting in the bathtub, he saw the water overflowing and felt his body being gently pulled up. He suddenly realized that he jumped out of the bathtub and went straight to the palace without clothes, shouting "Eureka" and "Foreka" all the way. It turns out that if the crown is put into water, the amount of water released is not equal to the amount of water released by the same weight of gold, and it must be mixed with other metals. This is the famous law of buoyancy, that is, an object immersed in a liquid is subjected to upward buoyancy, and its size is equal to the weight of the liquid discharged by the object. Later, this law was named Archimedes principle.
9. Science and Technology Speech
"Technology and Future" Speech
Hello, students and teachers present! I'm Yun Yun, and I'm preparing for Class One. Today, I have the honor to give a speech entitled "Technology and Future" here. I am proud, but a little uneasy. In recent years, we have seen the rapid development of science and technology in our great motherland, which makes me feel extremely proud. I am a China native. I remember a long time ago, there was almost only one purpose of mobile phones, that is, making phone calls. But a few years ago, mobile phones have changed a lot, not only in appearance, but also in many uses. They can be used to take photos, have meetings, surf the Internet, send short messages and so on, which makes our life more convenient and makes me more aware of the power of technology. However, I am just a fledgling student. But I want to think about technology and the future from the perspective of a student.
From the dream of genetic engineering to the promise of nanotechnology to ensure that you don't have to wash clothes; From the warmth of artificial intelligence "give you a lovely robot dog" to the wonder of transgenic technology "let mice grow human ears", new technologies are constantly being born, and every discovery of new technologies will make people ecstatic, because these new technologies are gradually improving our lives and let us know ourselves better. In the near future, China completed the whole genome sequencing of SARS virus for the first time, which is recognized as the most harmful disease in the world at present. But why can't other countries finish it first, while our country has just finished it? Quite simply, this shows that our country is not behind others, nor worse than others. Looking back on our motherland's past, from a country that has just started reform and opening up to a big country with a leading scientific and technological level, our motherland has experienced many ups and downs and experienced many difficulties and bumps, but our motherland has survived because we firmly believe that science and technology can not only change our destiny, but also change our future.
For our generation, the general feeling given to the society is a strong sense of competition and sufficient motivation to learn. Popular science knowledge is the focus of our attention, Einstein, Hawking and Bill Gates are the stars in our minds, and computer science, modern physics and chemical kinetics are influencing us all the time. We have understood the importance and universality of science and technology.
Although the prospect of technology creating a new life is fascinating and fascinating. But in the final analysis, it depends on our joint efforts. As the backbone of the future construction of the motherland, the burden on our generation of young people is really not light, and new opportunities are always accompanied by risks and challenges. However, we will not give up easily. We swear to our predecessors with our youth that we will never live up to their hopes.
Looking back at the course of civilization, it is the light of science and technology that sweeps away the darkness of ignorance in human history, and it is the fire of science that ignites the burning hope in human hearts; Science and technology support civilization, science and technology create the future, and the future is in our hands. Let's become explorers of knowledge, let's roam on unknown roads, and let's use our creativity to make the world we live in a better place.