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.
2. It is urgent to give a lecture on popular science knowledge.
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.
3. 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.
4. 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.
5. Understanding 600 words in scientific lectures is urgently needed.
Recently, we listened to a lecture. The title of this speech is "Advocating Science and Opposing Cults". It tells me that cults are established under the guise of religion or other names, which is extremely harmful to the normal production and living order of the state, society, families and individuals and the safety of life and property. The most essential feature of a cult organization is to develop its members by means of bewitching and cheating, and to control and destroy its followers.
Although cults embezzle some religious terms, their essence is antisocial, confusing people, inciting members to hate society and venting their dissatisfaction with reality. Cults also take advantage of the weakness of minors' low ability to identify and judge, and try their best to develop members among minors, which corrodes and poisons minors and causes irreparable damage to their healthy physical and mental growth. In a word, cults are one of the three major cancers in the world, which are also called terrorism and triad.
After listening to this lecture, I deeply know that cults do great harm to us. Only by fully realizing the harmfulness of cults can we avoid Liu Siying's bloody lesson: "A teenage girl became one of the victims of cults at the instigation of her mother and set herself on fire." I feel very sad now. If a living person, a healthy person, is controlled by that damn cult, it is still intact, but it is like a waste. Among them, some people must understand the harm of cults. Why did they take the wrong step? As the saying goes, "a slip of the foot makes a lasting regret, and then look back for a hundred years." Should their fate really be like this?
Therefore, we young people should remember the name "cult", never be confused by its heresy, advocate science, and face learning, life, society and a bright future with a positive attitude. Friends, let's advocate science and oppose cults together, shall we?
6. I urgently need a lecture on scientific knowledge in primary schools.
Some knowledge of primary school science should be useful to you! ! ! 1. A luminous object is called a light source.
Pinhole cameras are made according to the principle that light travels along a straight line. Slide projectors, film projectors, cameras and video cameras are all made according to the principle of convex lens imaging.
Periscope is made according to the principle of light reflection. 2. The pinhole imaging experiment shows that the light propagates along a straight line, which seems to be inverted.
3. When light shines on an object, it is blocked by the object and changes the original propagation direction, which is called light reflection. When light enters another transparent object from one transparent object, the propagation direction is deflected, which is called light refraction.
4. All kinds of objects can reflect light, and the reflection situation is different. Red objects reflect red light, yellow objects reflect yellow light, and objects of different colors reflect different colors.
White objects reflect light better than black objects. The smoother the surface, the stronger the reflective ability.
5. A common mirror whose surface is flat is called a plane mirror. Plane mirror imaging is formed by reflection of light.
The image in the plane mirror is the same size as the object, but the left and right are opposite. 6. A transparent lens with a thick center and thin edges is called a convex lens.
The convex lens has the functions of focusing, magnifying and imaging. 7. (Law of Convex Lens Imaging) Images formed by convex lenses are all inverted.
When the convex lens is close to the paper screen and away from the candle, a reduced image is formed; When the convex lens is far away from the paper screen and close to the candle, an enlarged image is formed. 8. The main part of the eye is the eyeball; It consists of pupil, lens, retina and optic nerve.
Pupils are like the aperture of a camera, which can control the intensity of light; Lenticular convex lens can image objects; The paper screen in retina imaging experiment can reflect the image. 9. How do we view the objects around us? ) Some objects around us will glow by themselves, while others will reflect the light of other objects.
When the light they emit or reflect enters the eye through the pupil and lens, the images of these objects will be formed on the retina; The optic nerve connected to the retina immediately reports these light signals to the brain, and we see these objects. 10. (Why can objects near and far be seen clearly? ) Adjust the convexity of the lens by pulling the muscles of the lens.
Muscle contracts, lens convexity becomes larger, and eyes can see nearby objects clearly; The muscles relax, the convexity of the lens becomes smaller, and the eyes can see the distant objects clearly. Healthy eyes have strong lens adjustment ability, and objects far and near can see clearly.
1 1. (How is myopia formed? If you look at nearby objects for a long time, the muscles pulling the lens are always in a state of tension, and you will be tired and lose your ability to adjust. If you look at distant objects, you will become blurred. This is myopia. 12. To prevent myopia: 1) Read and write correctly, and keep the distance between eyes and books at about 30 cm; 2) After reading for about an hour, take a break for a few minutes and look into the distance for a while; 3) Don't read in strong light or weak light; 4) Don't read while lying down or walking; 5) Children should always do eye exercises.
13. (How did the rainbow form? After sunlight passes through the prism, it will be dispersed into seven colors: red, orange, yellow, green, blue, indigo and purple. Sunlight is a mixture of seven colors.
When it rains (or after rain), many small water droplets are suspended in the air, which will scatter sunlight into seven colors like a prism to form a rainbow. 14. Rock is composed of minerals.
Granite is composed of quartz, feldspar and mica. 15. The minerals with mining value gathered together are called minerals.
What can be used as fuel is called energy minerals, such as coal, oil and natural gas. They are not only fuels, but also important industrial raw materials. After refining coal, coke, gas and coal tar can be obtained.
What can extract metals is called metal minerals. Such as iron ore, copper ore and tungsten ore.
How is coal formed? ) The underground distribution of coal is layered, mostly sandwiched between sandstone and shale. Coal is an ancient plant buried underground, isolated from the air, and gradually formed after hundreds of millions of years of changes under the action of high temperature and high pressure.
The energy contained in coal, oil and natural gas originally came from the sun. 17. The mining methods of minerals mainly include open-pit mining, underground mining and pipeline mining.
Oil and natural gas belong to pipeline mining. Solid minerals such as coal can be mined in the open air or underground.
18. All kinds of minerals are formed under certain conditions: some are formed during magmatic activities, and some are formed during weathering and deposition of rocks. 19. China is the first country in the world to discover and utilize oil and natural gas. The word "oil" first appeared in the works of Shen Kuo, a famous scientist in the Song Dynasty.
Under the guidance of geologist Li Siguang's theory, one big oil field after another has been developed. Why should mineral resources be used rationally? ) Mineral resources are indispensable natural resources for human production and life.
The mineral resources on the earth are limited and non-renewable, so they must be mined and utilized in a planned way, and must not be misused. 2 1. The ancestors of domestic animals are all wild animals, and poultry are domesticated by wild birds.
According to human needs, the process of cultivating wild animals into domestic animals is called animal domestication. 22. Biological revelation: fishing boats, paddles, rudders and submarines; A thatched saw; Birds-airplanes; Eggshell-thin shell roof; Bat radar; Long curly blade-cylindrical blade bridge; Fly-eye camera; People-robots; Human brain-electronic computer.
According to the phenomenon that the sun, moon and stars rise in the east and set in the west, we know that the earth has been spinning, and the direction of rotation is from west to east. It takes about 24 hours (one day) to rotate.
24. (How is day and night formed? The earth is a sphere, and the sun can only illuminate half the earth. The side facing away from the sun is daytime, and the side facing away from the sun is night. When the earth keeps spinning, the phenomenon of alternating day and night will appear.
The diurnal variation is caused by the rotation of the earth. 25. The earth revolves around the sun at the same time. This movement is called revolution, and the direction of revolution is also from west to east. The revolution time is one year (or 365 days).
The revolution of the earth forms the four seasons. 26. The moon revolves around the earth, and the revolution direction is from west to east. The phase change of the moon is caused by its revolution.
On the fifteenth night of the lunar calendar, the moon is always in the east. 27. (Moon phase.
7. Ask for a lecture on science and technology, 700 words.
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 "giving you a lovely robot dog" to the spectacle of transgenic technology "making 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 making 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 the concerted efforts of all of you, Qi Xin. 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.
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 the completion, the king suspected that the craftsman had mixed silver into the crown, but the crown was as heavy as the pure gold originally given to the goldsmith. 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. It is urgent to give a lecture on popular science knowledge.
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.