Model essay on physics 1: the utility of physics in scientific and technological innovation Abstract: This paper discusses that the discovery of X-rays not only has a great influence on medical diagnosis, but also directly affects many important discoveries in the 20th century. The invention of semiconductors led the microelectronics industry to dominate the 20th century and promoted the rapid development of information technology. Physics is the foundation of computer hardware. The theory of atomic energy is put forward, which makes atomic energy gradually replace petrochemical energy and provide huge clean energy for mankind. The theory and invention of laser make laser widely used in industrial and agricultural production, medical treatment, communication and military affairs. The invention of blue LED will illuminate the whole 2 1 century. Facts tell us that physics promotes scientific and technological innovation, from which we can draw a conclusion that physics is the source of scientific and technological innovation. It shows people that universities, as places to train talents, science and engineering should attach importance to college physics courses.
Keywords: x-ray; Semiconductors; Atomic energy; Laser; Blue LED technology innovation; college physics
1 Introduction
Physics is a science that studies the most basic structure, the most common interaction and the most common law of motion in the material world [1-3]. Its content is extensive and profound, and its research methods are diverse and ingenious. It is considered as the foundation of all natural sciences. Throughout the development history of physics, we can find that its scientific ideas and methods can effectively promote the cultivation of students' ability and the formation of knowledge. Every new discovery will promote the scientific and technological innovation and development of human society. Because of this, college physics has become a compulsory basic course for science and engineering majors in colleges and universities. According to the requirements of the relevant documents of the Ministry of Education [4-5], the minimum class hours of college physics courses are 126, among which the non-physics majors in science and normal universities are not less than 144. The minimum number of hours for college physics experiments is 54 hours, including no less than 64 hours for engineering and normal non-physics majors. However, the survey shows that many universities (especially newly-built undergraduate colleges) do not offer college physics and its experiments in strict accordance with the basic requirements of the curriculum promulgated by the Ministry of Education. Wide caliber, application type? At present, the total hours of college physics and its experimental courses are actually only 32-96 hours, which is far below the minimum standard required by the Ministry of Education (180 hours). How can you teach rich and profound college physics in so little time? How can we really play the role of college physics? So some departments only require mechanics, some only require heat, and some only require electromagnetism. Faced with this situation, college physics teachers are in a helpless state when teaching college physics. From the forum of college physics course report, we know that this is not the practice of individual schools, but the practice of the whole country. As we all know, force, heat, light, electromagnetism and atom are a complete system, which are interrelated and indispensable. This practice of solving the shortage of class hours at the expense of reducing the teaching content is tantamount to cutting the foot and fitting the shoes. It is a reflection of managers' backward ideas. This paper does not discuss physics as a compulsory basic course for science and engineering, but only discusses the proposition that physics is the source of scientific and technological innovation, in order to improve the education administrators' understanding of the importance of college physics curriculum.
Physics is the source of scientific and technological innovation.
Not to mention the development of mechanics and thermodynamics, the steam engine triggered the first industrial revolution, and Europe realized mechanization; Not to mention the development of electromagnetism founded by Coulomb, Faraday, Lengci, Ampere and Maxwell. This led to the second industrial revolution marked by electric motors, and electrification was realized in Europe and America. These two industrial revolutions did not take place in China, which made China fall behind in modern times. This paper focuses on the great promotion of modern physics to science and technology, and draws the conclusion that physics is the source of scientific and technological innovation. William? 50000.000000000 105 roentgen discovered x-rays, which do not deflect in electric and magnetic fields and have strong penetrating power. Because it was not known at that time, it was named X-ray. It was not until 19 12 that MaxvonLaue used the crystal lattice as a diffraction grating to determine that it was a light wave. The wavelength is about 10- 10m [6]. Roentgen won the Nobel Prize in Physics 190 1 year. The X-ray he discovered pioneered medical imaging technology, using X-ray machine to detect bone lesions, chest X-ray to diagnose lung lesions, and abdominal X-ray to detect intestinal infarction. CT imaging also uses X-ray imaging. CT imaging can not only provide two-dimensional (2D) cross-sectional images, but also provide three-dimensional (3D) images, which can clearly display the internal structure of the detected part and accurately determine the location of the lesion. Today, all hospitals have set up radiology departments, and X-rays are fully used in medicine. The discovery of X-rays not only had a great impact on medical diagnosis, but also directly affected many important scientific discoveries in the 20th century. 1866017 William henrgbragg and William? Lao Lun? WillianLawrenceBragg provided the Bragg equation [6, P 140]2dsin? =k？ (k= 1，2，3？ ) where d is the lattice constant. Is the angle between the incident light and the crystal plane. For the wavelength of X-ray, the Bragg sons proposed to use X-ray diffraction to study the structure of crystal atoms and molecules, and founded the discipline of X-ray crystal structure analysis. Prague and his son won the 19 15 Nobel Prize in Physics. Today, X-ray diffractometer is widely used not only in physical research, but also in chemistry, biology, geology, minerals, materials and other disciplines. All scientific research institutes and most colleges and universities engaged in natural science research have X-ray diffractometers. Tang musun (w? Thomson) discovered the electron, the electron mass me=9. 1 1? 10-3 1kg, electron charge e=- 1.602? 10- 19C。 The charge of electrons led to the revolution in the 20th century. In 2007, Bardeen, Brighton and shockley in the United States found that Ge crystal had amplification effect when they were studying semiconductor materials. They invented transistors, which quickly replaced electron tubes, and then transistor circuits continued to develop to miniaturization. Kilby, an American engineer, manufactured the first batch of integrated circuits .20058.6060606060686 197 1 year, hoff of Intel company integrated all the functions of computer central processing unit on one chip and made the world's first microprocessor. By the end of 1980s, the number of components integrated on the chip had exceeded 10 billion. Microelectronics technology has changed human life, which dominated the 20th century and entered 265438. Electrons are not only charged but also magnetically charged.
Uhlenbeck 1925? Uhlenbeck-Goodmitt put forward the spin hypothesis. Every electron has spin angular momentum s rolling, and its projection in any direction in space can only take two values, Sz=? H2； Electrons have charge magnetism, and the magnetic moment of each electron is MSz= Xiong? b(？ B is Bohr magneton) [7]. The charge magnetism of electrons has been sleeping for more than half a century until 1988 Abel? Albert Ford and Peter? Gruenberg (PeterGr? Nberg) found that in Fe/Cr multilayer films, the resistivity of materials changed significantly due to the change of magnetization state of materials. The mechanism is that antiferromagnetic coupling occurs between adjacent ferromagnetic layers through nonmagnetic Cr, and the resistivity is large when no magnetic field is added. When the magnetic field is applied, the magnetic moments of adjacent ferromagnetic layers are arranged in the same direction, so the electron scattering is weak and the resistivity is small. Giant magnetoresistance (GMR) is proposed by using magnetism to control the transmission of electrons. (0)+? (H)？ (0)? /kloc-where is 0/00%? (0) Zero field resistivity,? (h) The discovery of giant magnetoresistance effect has aroused great concern in scientific and technological circles. 1994, IBM developed GMR effect based on the principle of giant magnetoresistance effect. New read head? In the past, the magnetic head was made of ferromanganese, and the magnetoresistance MR was only 1%-2%, while the new read head was about 50%, which increased the recording density of the disk by 17 times, which was beneficial to the miniaturization of devices. Notebooks and MP3 players appeared only in MR with a new read head, and GMR effect was widely used in magnetic sensors, numerical control hangars, contactless switches, rotary encoders and so on. Phil and Peter. Gruenberg won the 2007 Nobel Prize in Physics. 1993.Helmolt et al. [9] observed that the MR in La2/3Ba 1/3M3NO3 thin film is as high as 105%, which is called giant magnetoresistance (CMR). Perovskite oxides have such high magnetoresistance. It has attractive application prospects in magnetic sensing, magnetic storage, spin transistor, magnetic refrigeration and so on, which has attracted great attention of researchers in condensed matter physics and materials science [10- 12]. However, the CMR effect has not been applied in practice, because an external magnetic field of Tesla magnitude is needed to achieve a large MR, and the problem is that the physical mechanism of CMR has not been really understood. As far as a particle is concerned, if its energy is reduced due to its internal process, its static mass will also be reduced accordingly. A famous mass-energy relationship △E=△m is proposed, in which △m represents the reduction of the total static mass of particles after reaction and △E represents the energy released by nuclear reaction. Einstein also put forward a way to realize thermonuclear reaction: it is not impossible to test this theory with objects with highly variable energy (such as radium salt). According to Einstein's important physical theory, physicists discovered nuclear fission of heavy atoms in 1938. Nuclear fission was first used in war. 1On August 6th and 9th, 945, the United States dropped atomic bombs on Hiroshima and Nagasaki, Japan, forcing Japan to accept the Potsdam Proclamation, and announced its unconditional surrender in August 15. Later, atomic energy was quickly used peacefully. Obninsk nuclear power station near Moscow was put into operation in 1954. In 2009, there were 104 nuclear power plants in the United States, accounting for 20% of China's total power generation, and 59 in France, accounting for 80%. Japan has 55 nuclear power plants, accounting for 30%. By April of 20 15, China had 23 nuclear power units in operation and 26 nuclear power units under construction, with a production capacity of 2 1.4 GW, accounting for less than 3% of China's total power generation. Therefore, China proposed to vigorously develop nuclear power, and set the goal that the total installed capacity of nuclear power will reach 58 GW by 2020. On the other hand, the emission of carbon dioxide has effectively solved the energy crisis. Using deuterium and tritium in seawater for nuclear fusion can generate huge energy, which controlled nuclear fusion is studying. If controlled nuclear fusion succeeds, it will provide inexhaustible energy for mankind. By then, the energy crisis will be completely alleviated.
The most outstanding achievement in the 20th century is the computer, and physics is the foundation of computer hardware. Since the advent of 1946, computers have experienced the first generation to the fifth generation. With the progress of physics, electronic components in computer hardware have experienced electron tubes, transistors, small and medium-sized integrated circuits, large-scale integrated circuits and very large-scale integrated circuits. The main memory is made of magnetic material. With the progress of physics, the performance of magnetic materials is getting higher and higher, and the hard disk of computer is getting smaller and smaller. Recently, at the 16th National Conference on Magnetism and Magnetic Materials (20 15, 10, 2 1? 25) It was learned that the Center for Strong Magnetic Field of Chinese Academy of Sciences and the Institute of Physics of Chinese Academy of Sciences are tackling key problems with skyrmions, which have topological nano-magnetic structure. In the future, the hard disk of notebook computers will only be the size of peanuts, and the hard disk of ipod tablet computers will be reduced to the size of rice grains. Quantum mechanics gave birth to tunnel diode, which led to the research on the size limit of electronic devices. The invention of optical fiber provided data channels for computer networks.
19 16, Einstein put forward the principle of being irradiated by laser. 44 years later, Theodore of Columbia University? TheodoreMaiman made the first laser in 1960 [14]. Laser has been widely used in medical, agricultural, communication, metal micromachining and military fields because of its advantages of good monochromaticity, good coherence, good directivity and high brightness. Let's not talk about the application of laser in other fields for the time being, just talk about the application of laser processing technology in industrial production. Small light spot and concentrated energy; The laser beam is easy to focus and guide, which is convenient for automatic control; Safe and reliable, will not cause mechanical extrusion or mechanical stress to the material; The cutting surface is smooth without burr; The cutting surface is small, and the kerf is generally 0. 1-0.2 mm; Suitable for processing large-volume products. Widely used in automobile, airplane, microelectronics, steel and other industries. In 20 14 years, the total revenue of China's laser processing industry alone was about 27 billion RMB, of which the sales of laser processing equipment reached 21500 million RMB.
The Nobel Prize in Physics in 20 14 was awarded to two or three scientists, Isamu Akasaki, Amano Miyuki and Sun Yat-sen Xiu, because they invented the blue light-emitting diode (led) to help people get white light in a more energy-saving way. Their outstanding contribution is that among the three primary colors of red, green and blue, red led and green led have long been invented, but the manufacture of blue led has been a long-term problem. The three of them invented the blue LED in 1990s, so that all the tricolor LEDs were found, and the manufactured LED lamps were used for lighting, which made consumers feel comfortable. The energy consumption of this LED lamp is very low, less than 65,438+0/20 of that of ordinary light bulbs, and 40% of the electricity generated in the world is used for lighting. If all ordinary light bulbs are replaced by LED lights, the amount of energy saved in the world is amazing! Physical research has brought immeasurable benefits to mankind. 20 10 Andre, a scientist at the University of Manchester, UK? Andreheim and Constantine? Kon-stantinNovoselov won the Nobel Prize in Physics for inventing graphene. At present, integrated circuit transistors are generally made of silicon materials. When the size of silicon material is less than 10 nanometer, the stability of the transistor made of it becomes poor. Graphene can be carved into a single electron transistor with a size smaller than 1 molecule. In addition, graphene is highly stable. Even if it is cut into components with a width of 1 nm, its conductivity is very good. So it is generally believed that graphene will eventually replace silicon, which will lead to the revolution of electronic industry [14] .20438+02, French scientist Shojaei? SergeHaroche and American scientist David? DavidJ.win-land，in？ Breakthrough experimental methods make it possible to measure and manipulate a single quantum system? Their breakthrough method makes the research in this field take the first step towards building a new ultrafast computer based on quantum physics [16].
In 20 13, the experimental team led by Tsinghua University academician Xue Qikun, the Department of Physics of Tsinghua University and the Institute of Physics of Chinese Academy of Sciences observed the quantum anomalous Hall effect for the first time. As early as 20 10, Chinese theoretical physicist, Dai and professor cooperated to propose that magnetically doped three-dimensional topological insulators may be the best system to realize quantum anomalous Hall effect. Under the guidance of this theory, Xue Qikun and others carried out experimental research and observed the quantum anomalous Hall effect for the first time. When we use a computer, we will encounter problems such as computer fever, energy loss and slow speed. This is because the electrons in the chip have no specific orbits and collide with each other under normal circumstances, and the quantum Hall effect can make a rule for the movement of electrons. Electrons spin up on one runway and down on the other, just like on a highway. Go ahead. Move slowly, no electrons collide with each other, no heat loss. Through density integration, the size of computers in the future will be greatly reduced, and supercomputers with hundreds of billions of times are expected to be as big as the current iPad. Therefore, the application prospect of this scientific research achievement is very broad [17]. Every major discovery and invention in physics will open up a new world, bring about industrial revolution, promote social progress and create huge material wealth.
3 Conclusion
Discovery or invention of X-ray, electron, semiconductor, atomic energy, laser, blue LED, etc. Greatly promoted the progress of mankind. Naturally, it is concluded that physics is the source of scientific and technological innovation. When we open the door, famous universities in the United States attach great importance to college physics. The total hours of all public physics courses in the first and second grades of California Institute of Technology are 540. Britain, France and Germany also have 400-500 class hours [18]. Only the college physics course of China University of Science and Technology has been in line with international standards. Taking their mathematics and applied mathematics as an example, the freshman offered 80 classes of mechanics and heat, and college physics? Basic experiment for 54 hours; Sophomore: electromagnetism 80 hours, optics and atomic physics 80 hours, college physics? 54 hours comprehensive experiment; Junior year: 60 hours of theoretical mechanics and 408 hours of college physics and experiment. Today, colleges and universities should attach importance to physics teaching. Science and engineering in colleges and universities should give enough college physics courses and college physics experiment hours in accordance with the Basic Requirements for College Physics Courses/Experimental Teaching of Non-physical Science and Technology Subjects issued by the Teaching Steering Committee of Non-physical Majors in Colleges and Universities of the Ministry of Education.
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Physics Model II: Application of Holographic Teaching in Junior High School Physics I. Strategies of Holographic Teaching in Junior High School Physics Teaching
1. Using holographic theory, reasonably select and match junior high school physics teaching courses.
After the new curriculum reform, physics classroom teaching has changed from the traditional teaching content to the process of physics, the core of which is to provide students with opportunities and create opportunities. Therefore, in physics teaching, teachers should be good at using holographic teaching theory, reasonably choose and match the course types according to students' life experience and existing knowledge background, guide students to retell physics knowledge in various ways, encourage students to find and ask questions, and then stimulate students' interest in learning physics and cultivate students' innovation and inquiry ability. For example, when talking about electrostatic shielding, first lead students to do electrostatic shielding experiments and get the correct results. Suddenly a student asked a question? When the hair dryer is used to blow the head, the hair dryer has an influence on the TV signal, so is the electrostatic shielding not completely established? So I led the students to do the following experiment: put one mobile phone in a closed carton, make a phone call with another mobile phone, and the students heard the noise. Ask the students to think again. If you put your mobile phone in a metal cage where you have done experiments, can you hear the bell? Most students can't guess from the principle of electrostatic shielding. However, after putting the phone in the cage, you can still hear the bell. The students are confused. Is the electrostatic balance theory wrong? Did you make everyone think about this phenomenon? Static electricity then explained to the students that the mobile phone signal is electromagnetic wave rather than static electricity, which belongs to alternating electromagnetic field. When it meets the metal mesh, the metal mesh will induce electromagnetic waves with the same frequency, but the intensity will be reduced, so the cell phone bell can still be heard in the cage, which explains why the hair dryer will have an impact on the TV signal. In this way, students' understanding of physical knowledge can be deepened through the reproduction and comparison of physical knowledge, thus improving the teaching quality.
2. Using holographic theory, choose the appropriate teaching methods according to the physics textbooks and learning conditions.
In physics teaching, the difficulty of arranging knowledge points in physics textbooks is different. If all knowledge points are explained according to the same teaching method, students who are easy to understand will be relatively skilled, while students who are relatively difficult may be confused, which is unfavorable to students' learning. In this way, when using holographic theory, physics teachers should not blindly follow a teaching method to explain, but should pay attention to the changes in teaching methods, so that students can master knowledge points skillfully. In addition, each student's mastery of knowledge points is different. Some students may have a good grasp, while others have a poor grasp. Therefore, physics teachers should choose teaching methods according to students' learning situation, not only to take care of those students with poor knowledge, but also to let students with good knowledge learn more. For example, explain to classmates? Measurement? Relative knowledge points are relatively easy for students and easy to come into contact with in daily life. Therefore, when using holographic teaching theory, teachers can explain the main idea of the content to students first, and then explain the main knowledge points carefully. After this explanation, students can easily master the knowledge of measurement. While explaining to the students? The laws of optics? Sometimes, students are easily confused about the rules, if the physics teacher still follows the explanation? Measurement? When explaining this method to students, it is difficult for them to master it. Therefore, teachers should change the teaching methods, not only to explain the theory to students, but also to lead students to carry out experiments on this law, so as to deepen students' understanding of the optical law and make them better grasp the knowledge points. 3. Using the holographic theory, select the appropriate evaluation method according to the content and characteristics of knowledge. In physics teaching, it is very important for physics teachers to evaluate students. Some evaluation methods will stimulate students' interest in learning physics knowledge, while others may make students suffer, thus losing their interest in learning physics. Therefore, teachers should make rational use of holographic theory and choose appropriate evaluation methods according to the content and characteristics of knowledge to stimulate students' interest in learning physics. For example, when students are asked to answer questions in class, they will be given a positive evaluation if the answers are correct, and they will be given a positive evaluation if they are wrong. Holographic theory is used to tell them that they have not chosen the right way in the process of discussing knowledge, so that they can discuss in the right way, which will not only let students know their own shortcomings, but also encourage them, so that students will be willing to learn, thus greatly improving physics teaching.
Two. Concluding remarks