Presupposition and generation in classroom teaching. Question 1. Traditional classroom teaching presupposes too much. We know that teaching is a complex activity, which requires teachers to make careful arrangements, make detailed plans and make full preparations. These are the premises. However, traditional teaching is almost entirely the product of presupposition. Teachers only have textbooks and teaching methods in their minds, and regard students as a container to be loaded. Then, according to the pre-designed lesson plan, the teaching content is reversed layer by layer. Little attention is paid to the development of students and their living conditions in the classroom. Students are banned if they are out of line, which makes the original lively and interesting science class extremely dull, mechanical and rigid; The glow of students' subjective spirit and the flicker of innovative spirit are almost degraded and lost. 2. Generative classroom teaching. All for the development of every student is the core idea of the new round of curriculum reform. As the forefront of the new curriculum reform, the classroom should be student-oriented and highly aware that students are the main body of classroom learning. Therefore, when students with different ideas and colorful personalities take part in classroom learning with their knowledge, experience, thinking, inspiration and interest, and become the main body of classroom learning, and have equal dialogue, emotional collision and life exchange with teachers in a democratic and harmonious atmosphere, our classroom will show unprecedented richness and complexity, that is, it is full of generativeness. In such a classroom; Our students will let passion flow, flowers of thought bloom and words of wisdom flow; This kind of classroom is truly student-oriented and the ideal classroom needed by the new curriculum reform. Second, generate the relationship with the preset. Traditionally, generation and presupposition are a set of opposing concepts. Wonderful generation is often unpredictable. In fact, the wonderful generation can be preset. However, this presupposition is not in the traditional sense. It is a student-centered preset, a humanized preset and a flexible preset. Teachers should not only compile teaching plans in the traditional sense, choose teaching methods and design teaching models, but also give more consideration to students as the main body of learning, presuppose what new teaching resources they may generate, and give themselves a flexible disposable space so that they can safely accept and embrace classroom generation. Let's talk about several presuppositions that students are most likely to produce generative teaching resources in science classroom teaching. 1. The premise of academic change Mr. Tao Xingzhi said: We must become children before we can become their teachers. As we know, students are a group of living individuals. Their knowledge, experience and cognitive level are different, and the degree of preparation before class is also different, so our classroom teaching often has some changes. In order for students to complete the construction of knowledge, we must presuppose our teaching from the perspective of students. So before class, we should fully understand the students, their knowledge reserves, their preparation before class, predict all possible classroom changes, think about their countermeasures, and then store them in our own flexible preset space. 2. It is difficult to ask questions by default. Skeptics have the opportunity to know, realize and make progress. The new curriculum standard also requires students to dare to put forward their own opinions and make their own judgments in communication and discussion. Not only as a book, but also as a teacher, dare to put forward your own views and make your own judgments on the key points, doubts, difficulties and ambiguities of the article. The emergence of these unexpected problems makes the generated teaching resources more accidental, which is difficult for us to control at the moment. Therefore, when preparing lessons, we should make in-depth presuppositions for the above students. 3. Presupposition, expansion and extension of new curriculum standards advocate the development and utilization of curriculum resources. Attach importance to the cultivation of scientific inquiry methods. It is believed that the extension of scientific learning is equal to the extension of life, which requires us to expand the field of scientific learning and broaden students' horizons in the intersection, infiltration and integration of different contents and methods. Specifically, students are required to obtain information by consulting a large number of materials and reading the dictionary of life without words to help them study better. Because the methods, ways and contents of students' expanding learning are rich and colorful, it is easy to produce new and unpredictable teaching resources. This requires us to presuppose what students think is easy to expand, understand the ways and means they may use to expand, and be sure. However, it is undeniable that although we have made sufficient and student-centered humanized presuppositions, sometimes many situations in the classroom are unpredictable. As Bloom said, people can't predict the all-round results of teaching. Because teaching is an art, in the face of unexpected classroom generation, we should establish a correct classroom view, flexibly handle and use the generative resources in the classroom, and record and reflect in time to pave the way for the next preset and lay a solid foundation. So I think presupposition and generation are not incompatible, but compatible, just like twin brothers. Third, the scientific response to generative resources in the classroom is first and foremost leisurely. When the classroom generates new teaching resources, whether it is preset or not. Teachers should give themselves a calm mind, take their time and believe that they have fully preset students and texts; Facing this generation, I have a well-thought-out plan, which will be solved in equal dialogue and cooperation with students and texts. Second, learn to listen. There are two purposes of learning to listen: one is to capture effective information from the generative resources that are fleeting and will be ignored carelessly. The second is to give yourself a calm mind and time space to think and analyze the captured information. When listening, the teacher should look at the students with his own eyes, express your understanding and approval with a nod and smile, and give appropriate encouragement. While capturing effective information, it also conveys respect for students. Thirdly, he is good at guiding, which can be divided into two types: one is to follow the students' questions and give them to the whole class so that all students can actively participate and think together. The author calls it a logical conclusion. For example, in "Moon Phase", a student objected to the pictures in the textbook: Why do the first quarter moon and the second quarter moon look like the western moon? The teacher didn't express his thoughts directly, so he pushed the boat with the current: Is there any classmate who has the same problem with him? When' tis once spoken, several students raised their hands. After these students answered, the teacher pushed the boat with the current: Yes, we proved by experiments that the first quarter moon is the bright sky in the west, so why is the second quarter moon in the textbook picture also the bright sky in the west? I sincerely admire your courage to boldly challenge authority, and finally it is a clever extension. In the above two cases, students' problems have been skillfully solved in the dialogue between teachers and students, but sometimes some problems cannot be solved on the spot. We should not only admit that we can't solve it, but also learn to extend it skillfully. For example, in the textbook Burning, after exploring whether the long candle goes out first or the short candle goes out first, a student puts forward a new question: Does the size of the lid and the length of the candle affect the answer to the question? The teacher immediately praised the student and asked the students to further discuss the problem after class and improve the conclusion in class according to the results. In this way, teachers not only properly handle the unexpected generation in class, but also protect students' curiosity, and at the same time organically combine classroom inquiry with extracurricular inquiry. Suhomlinski, a famous educator in the former Soviet Union, said: The skill of education is not to foresee all the details of the classroom, but to make corresponding changes skillfully according to the specific situation at that time. Obviously, when we regard science classroom teaching as an important life course and a meaningful part of life for teachers and students, we will re-understand and organize science classroom teaching from the height of life with the concept of dynamic generation, correctly grasp the relationship between presupposition and generation, and establish a dynamic new science classroom, so that the emotions and wisdom of teachers and students will collide!