Text: Teaching is an art. We should use this art to make chemistry class more exciting and efficient from all aspects and factors, and make junior middle school chemistry, a newly opened natural science, a happy learning world for students. For junior high school chemistry, students may not have mastered their own unique learning methods in the learning process, so we should use the art of teaching to let students learn chemistry methods in the learning process, which saves time and effort. Teaching is always instructive. Therefore, combined with the teaching mode of "guiding self-study and improving energy through practice" in our school, this paper discusses how to build an efficient classroom: 1. Simplicity and effectiveness of the classroom are the central extreme principles of building an efficient classroom, also known as the principle of simplicity, that is, the most concise mode or law is used to contain and concentrate the most abundant things and phenomena. Therefore, chemistry class does not have to be gorgeous, but in the teaching process, students should understand the key points, difficulties and knowledge points in the simplest, most direct and clearest way. Just like a sword, go straight to the point, there is no need to have so much ostentation. Because of this, we let students preview before chemistry class (such preview can give some guidance and make students study more effectively), and then let students interact or ask questions directly in class. In this way, classroom learning is very direct and simple, so simple that students can understand after discussion, and teachers who don't understand after discussion will give guidance. In short, it is necessary to "intensively cultivate". Since we want to do intensive lectures in class, teachers should do the following: 1. Fully preparing lessons is the foundation. As the saying goes, sharpening a knife does not miss the woodcutter. Only by preparing lessons well and being prepared can teachers improve classroom efficiency. In classroom teaching, the relationship between teachers and students should not be the relationship between actors and audiences, but the relationship between directors and actors. This is what we often call the "teacher-led, student-centered" teaching model. Teachers should figure out what to do before giving lectures, just like the director's script. The important and difficult contents of this section, how to break through and how to implement it, should be thought out before class to achieve the purpose of intensive listening. For example, when I was teaching the basic operation of chemical experiment in the third quarter of chapter 1, I imagined that the podium was completely given to my students in the process of preparing lessons. I put the instruments and some drugs on the experimental platform in advance, and let the students observe for themselves. Then I talked about the precautions in the experimental operation, and asked the students to come to the podium to explain the precautions in the experimental operation while demonstrating. After the demonstration, let other students correct and evaluate. In this way, teachers and students interact, students interact, the classroom atmosphere is active, students learn hard, and teachers teach easily. It changed the situation that teachers talked too much and students were sleepy in the past, and played a very good role in the classroom. Only in the process of preparing lessons, we must imagine that class can be targeted. In order to really do intensive lectures, teachers must carefully design every sentence and question in class, carefully design every teaching link, and try to avoid the waste of teaching resources and time. 2. Classroom intensive reading teaching is the key. Classroom is the main position of teaching and learning. No matter what kind of education is carried out and to what extent, it is always a truth that teachers, as organizers and implementers of classroom teaching, realize teaching objectives, optimize teaching process and pursue high efficiency of classroom teaching. So, what kind of classroom is efficient? The most important thing is to concentrate in class. From the point of view of economics, the classroom should be a classroom that obtains the maximum learning benefit with the minimum investment in teaching and learning. To measure whether classroom teaching has achieved high efficiency from the perspective of new curriculum, we should first look at whether students' knowledge acquisition, ability growth and changes in emotions, attitudes and values have reached the corresponding dimensions; Secondly, it depends on whether the teaching process really improves the learning efficiency; Finally, it depends on whether the process of teaching and learning is harmonious, agile and full of vitality, and whether it can reflect the mutual encouragement and common growth of both teaching and learning. These final realization are to return the class time to the students, so the teacher should explain it concisely and accurately in class. As a student, he must be the main body of the performance, and as a teacher, he should focus on the process of classroom learning through leading guidance and on-demand, so that students can improve their learning efficiency. However, teachers can't take the place of students' "acting", and at most occasionally make guest appearances as "supporting actors", which requires teachers to give enlightening and on-demand lectures in class. Let your students fully "act" and "practice", enter the "role" in the process of full and effective practice, comprehend knowledge, understand principles and develop their abilities. 3. Feedback of Excellence is the proof of classroom efficiency. The next thing to consider is the problem of refinement. Refinement and timely feedback are complementary and inseparable in classroom teaching. If you just talk and don't practice, you can't understand students' learning situation, and you can't feedback students' mastery of knowledge points. Printing exercises from a large number of reference materials to students and engaging in sea tactics is not only a waste of students' time, but also kills their interest in learning chemistry. In order to be concise and to the point, we now adopt the "exercise clipping method", that is, after teachers know the contents of the textbook in detail (including illustrations, experimental activities and exploration, discussion, materials, exercises, etc.), they determine the key points and difficulties. They cut and paste valuable topics from several reference books onto a blank sheet of paper and organize them into a test paper. How to make students master key knowledge? What methods are you going to take to break through the difficulties? "What knowledge needs to be re-integrated?" Wait, it can only be solved by teachers studying textbooks and delving into the key points and difficulties of knowledge points. It is believed that this can not only save students' time in writing chemistry homework, but also enable students to practice in a targeted way, thus greatly improving the teaching effect of chemistry class. In short, the purpose of timely feedback is to make students seriously understand the teacher's lectures, understand and master knowledge, and learn to think, learn to learn and learn to create in this process. Second, paying attention to the teaching of learning methods is the basis of building an efficient classroom. The ancients said: Give people fish, only one meal; Teach people to fish and enjoy it for life. Teaching students to learn must attach importance to the teaching of methods, that is, teaching students to learn and think. As a basic comprehensive subject, chemistry is not only based on knowledge, but also on scientific thinking methods. Therefore, in teaching design, teachers must consider students' learning methods. Teaching methods adopted must promote students' understanding and mastery of learning methods, and teaching methods must serve learning methods. Only in this way can we improve the quality of classroom teaching and achieve twice the result with half the effort, thus improving classroom efficiency. Therefore, we should not only pay attention to the teaching of basic knowledge, but also pay attention to the cultivation of students' ability. We should teach students how to study. In chemistry classroom teaching, we should highlight the important role of scientific methods in the process of knowledge formation. Therefore, in chemistry classroom teaching, teachers should pay attention to effective guidance for students to acquire knowledge, and train students to extract relevant chemical information through observation, experiment, inquiry, communication and cooperation, so as to promote students to acquire new knowledge and new ideas in the process of forming chemical knowledge, so as to get all-round development. (for example, the cultivation of learning methods. Our current teaching emphasizes double basics. However, we have also seen this situation. Some students, especially female students, have a solid "double foundation", but their grades have been unsatisfactory. In this way, cooperative inquiry is better used in the teaching process and chemical experiments are arranged reasonably; The summary and evaluation in the model should not only make students comment on each other, but also make teachers focus on some learning methods and problem-solving methods, so that students can gain more and be more efficient in learning. 3. Chemical experiment is the key to build an efficient classroom. Chemistry is a natural science based on experiments. Experiments will produce problems and problem situations. A good experiment can arouse students' interest immediately. If students are puzzled and puzzled by some obvious phenomena during the experiment, thus stimulating their strong thirst for knowledge and giving them the motivation to explore, then the exploration and understanding of the unknown can be successfully completed. For example, in order to get the sequence of metal activity, we only need to create such an environment: put magnesium, zinc, iron and copper into dilute sulfuric acid respectively, and let students carefully observe whether hydrogen is released and how fast it is released, and then we can get whether the metal activity is fast or slow. Another example is that the composition of the air is determined by experiments: after the red phosphorus in the gas container is burned, the water rises to one fifth. I immediately put forward this question: Why does the water only rise by one fifth? Around this experiment, students' strong interest in inquiry was aroused and the problem of air composition was solved. Similarly, when learning the laboratory preparation method of carbon dioxide, the teacher does not necessarily need to explain it step by step, but designs a series of questions to guide it step by step: 1. What are the similarities and differences between the laboratory preparation methods, equipment and collection methods of oxygen and hydrogen? Why one needs heating and the other doesn't; One uses the upper row method and the other uses the lower row method? 2. How should the device for producing carbon dioxide be equipped with instruments? 3. According to the nature of carbon dioxide, how should it be collected, verified and filled? This series of questions are put forward on the basis of students' original knowledge and are coherent. Students can draw conclusions one by one through discussion. So I discuss that this content should be handled by the students themselves, and then they will go on stage to talk about their experimental design scheme and operate the whole experimental process by themselves. Other students observe that if there are objections, they can complement each other and encourage innovative design. Chemistry is an experimental science, so we must attach importance to and tap the role of chemical experiments. There is no clear grouping experiment for students in the new textbook. Many teachers are afraid of trouble. They either talk about the experiment but don't do it, or treat all the experiments as demonstration experiments, and even tell the students the answers to the experiments and let them memorize them. On the surface, it saves time and improves classroom efficiency, but the functions of chemical experiments in helping students understand chemical knowledge deeply, improving students' ability to analyze and solve problems, and cultivating students' ideas and methods of scientific inquiry have been obliterated. Teachers should cultivate students' experimental ability and teach them how to do experiments. It takes a process to cultivate students' experimental ability, but once this ability is formed, it will certainly promote teaching and benefit students for life, which is efficient from a long-term perspective and knowledge application. Therefore, teachers must pay enough attention to chemical experiment teaching. However, if students can't be effectively monitored during the chemical experiment, one possibility is that the experiment can't achieve the expected effect and waste time; Another possibility is that students accidentally hurt themselves by operating at will. Therefore, teachers must be strict with students in this respect, and students must know what to do, what not to do, what to do right and what to do wrong. For example, before chemistry experiment teaching, students must be clear about the basic requirements in chemistry laboratory, such as standardized operation and the use and storage of various drugs. Before each experiment, students should make clear the purpose of the experiment, design the experimental steps and make clear the problems that should be paid attention to in the experiment, review the experimental design of students in advance, and ask students to operate carefully according to the standardized steps; To do experiments with students, teachers and students should experience the process of experimental inquiry together, experience the happiness of success and the bitterness of failure, and jointly solve the problems encountered in the experiment. In addition, teachers should encourage students to ask questions boldly and answer their questions patiently, so that students can experience the joy of harvest in a harmonious and pleasant atmosphere. By listening, communicating and cooperating, they should devote themselves to learning, learn knowledge, develop their abilities and improve their personality. Fourth, the use of media should be simple and fresh. With the development of modern educational technology, the use of multimedia technology to assist classroom teaching has gradually been widely used in the teaching field. It is interesting and intuitive, which is not available in traditional teaching methods. It can fully mobilize the enthusiasm, initiative and creativity of teachers and students, and break through the difficulties in teaching, especially for the movement of some microscopic particles, slow chemical changes, instantaneous chemical reactions, chemical production processes, and some dangerous experimental descriptions and simulations, which is incomparable to any previous teaching method. In this case, teachers can easily achieve the teaching purpose through the "unconventional" simulation of multimedia technology and virtual technology, so that students can acquire knowledge in a pleasant, relaxed and intuitive environment. For example, when talking about the nature of carbon monoxide, because carbon monoxide is highly toxic, and there is no fume hood that produces toxic gas in the middle school chemistry laboratory, we can use online resources to complete the experiments on the flammability and reducibility of carbon monoxide. These vivid experiments sometimes stop, sometimes show, sometimes disperse, and sometimes combine, so that students can see at a glance, which will undoubtedly promote the improvement of chemistry teaching quality. 5. Reasonable design of "learning plan" to ensure the smooth implementation of efficient classroom teaching "learning plan" is a guiding material designed by teachers to guide students' autonomous learning according to the characteristics of teaching materials, teaching requirements and students' existing knowledge level, ability level, learning method characteristics and psychological characteristics. Its emphasis is how to arouse students' learning enthusiasm; How to lead students to acquire knowledge, ability and development actively? 1, "learning plan" design principle (1) exploratory principle. The main purpose of writing a study plan is to cultivate students' ability of independent inquiry learning. Therefore, the preparation of learning plan should be conducive to students' exploratory learning, so as to activate students' thinking and let students experience the joy of success in the process of re-understanding and solving problems. (2) Heuristic principle. The questions set in the study plan should be enlightening, which can fully mobilize students' thinking, let students understand the mystery of knowledge through autonomous learning, and cultivate students' agility and insight. (3) the principle of flexibility. Due to the different foundations of students, when compiling, the forms should be colorful, flexible and diverse, and the contents should also try to arouse the enthusiasm of students' thinking. (4) Gradient principle. The setting of questions takes into account the students' understanding level and ability as much as possible, and the steps are small and the gradient is low, so that most students can experience the joy of success, thus mobilizing the enthusiasm of students for further exploration. (5) the principle of innovation. When writing a study plan, we should emphasize content innovation and cultivate students' innovative thinking ability. 2. The content of the "learning plan" (1) focuses on guiding students to learn to learn and improving their ability to obtain information, analyze information, process information, apply information and evaluate information. (2) In-class "Learning Guidance Outline" transforms the learning materials or tasks of this class into concrete forms that students are interested in and easy to master, thus guiding students to learn quickly and effectively. Three aspects are highlighted in the design. First, study practice guidance, which mainly puts forward learning content, learning objectives, key knowledge, difficulty analysis, teaching time arrangement, as well as preparatory knowledge, tools and reference materials needed in the teaching process. The second is the content of learning guidance, which mainly puts forward learning requirements and requirements for knowledge, learning methods, thinking methods, learning emotions, will and attitude. , put forward the idea of autonomous learning, put forward key contents or discuss topics, etc. Its emphasis is "guidance", which mainly includes guiding students to learn law, Taoism, doubt and thinking. First, the guidance method refers to the method of guiding students to master the content of this lesson, so that students can learn to read and analyze by themselves. Two. Leading the way refers to guiding students to sort out the logical order of teaching materials, so that students can know by the way and see in order. Three. Guiding doubt refers to guiding students to learn to question and ask difficult questions by themselves, and also to learn to ask questions, so that students can guide and answer questions in depth when they are in doubt. Ⅳ. Guiding thinking refers to guiding students to think positively, giving them scientific thinking methods and letting them learn to think. The third is the evaluation method, which mainly puts forward the requirements and assessment methods of reaching the standard in class, and its purpose is to spur students to improve the efficiency of classroom learning. At an appropriate time, conduct a "five-minute classroom standard test" in the last class. Can stimulate students' enthusiasm for learning. It should be noted that different types of learning contents-elements and their compounds, basic concepts and chemical reaction principles, etc. The idea and content of designing a "learning plan" will be slightly different. Students consciously read textbooks by themselves, think independently, or conduct group experiments, exchange and discuss among students, compare what they want to learn, and enter the classroom with remaining problems, thus improving learning efficiency. To sum up, in order to achieve classroom efficiency, we must carry out classroom teaching reform. As long as we continue to study, practice, summarize and accumulate in teaching practice, give full play to the wisdom of the group, and constantly explore and tap our own potential, we will certainly achieve efficient classroom and save time and effort.