Thinking comes from doubt. Without problems, there is no thinking. Thinking always begins with solving problems. Therefore, in chemistry teaching, teachers should create new and different teaching situations by asking enlightening questions or questioning questions, create a good thinking environment for students, and let students deepen their understanding of knowledge through thinking, analysis and comparison. For example, when talking about the oxidation of nitric acid, it can be suggested that acid can react with various metals to release hydrogen, but why should hydrochloric acid or dilute sulfuric acid be used instead of dilute nitric acid when preparing hydrogen and hydrogen sulfide? When describing the properties of nitric oxide and nitrogen dioxide, we can use the comparative analysis of their properties to put forward the method of removing impurity nitrogen dioxide. In the teaching of hydrogen sulfide reduction, students are inspired to think: 1, hydrogen sulfide is an acidic substance, why not dry it with concentrated sulfuric acid? 2. What kind of reaction will happen between hydrogen sulfide and concentrated sulfuric acid? 3. Is hydrogen sulfide used as oxidant or reductant in the reaction? Stimulate students' enthusiasm for exploration by setting situations.
When setting questions, we should grasp the key points, difficulties and keys of the textbook. The content of the question should conform to the logical order of knowledge accumulation, connecting the preceding with the following, from simple to complex, knocking on the door of students' thinking, making students feel novel, causing continuous thinking, forming a lasting internal driving force, arousing students' ideological resonance, activating the classroom atmosphere, and effectively mobilizing each student's thinking enthusiasm, thus achieving unexpected results.
Second, heuristic teaching methods are often used.
Heuristic teaching means that teachers ask questions, give information, guide students to think independently in an inspiring way and actively explore the occurrence and development of knowledge. His advantage is that students not only gain correct knowledge, but also have a process of thinking, giving students an opportunity to explore, think and create themselves, so that students can experience themselves in learning, which not only cultivates their considerate ability, but also enhances their self-confidence. In teaching, we should not only teach students knowledge, but also master the development process of knowledge, learn scientific thinking and analyze methods to solve problems.
Of course, a class lasts only 4 0 minutes. If students are allowed to think and discuss most of the time, it will be difficult to complete the teaching task. Therefore, I fully prepare lessons before class, properly handle the teaching materials, and make the details appropriate and the key points clear, so I can't grab my eyebrows and beard. The analysis and discussion should focus on the central content, with distinct levels and careful design. The whole teaching process is interlocking. The front knowledge is the foundation of the back, and the back knowledge is the development of the front, so that students can feel nature and solve problems naturally. In addition, students should also give appropriate help when they encounter difficulties in thinking.
Third, train thinking ability in various forms.
1, analysis, comparative thinking training
In the process of teaching, new knowledge is constantly emerging and new concepts are constantly introduced. These knowledge and essentials are both related and different. For example, measuring cylinder, pipette, burette and volumetric flask are all volumetric instruments, which can produce a certain volume of liquid, and students are easily confused when using them. Only by guiding them to compare the influence of capacity range, calibration specification and shape on accuracy can students truly understand the purpose of each instrument and know which instrument to use under what circumstances.
Teachers should always consciously put forward confusing concepts for students to think about and compare, pay attention to some vague or wrong understandings, and analyze the reasons, so that students can grasp the essence of concepts, nip mistakes in the bud, make the knowledge they have learned correct and reliable, and improve their ability of analysis and comparison.
2. Training of abstract and generalized thinking
The input of information induces thinking, arouses suspicion and leads to problems. Asking questions always hopes to solve problems, in fact, it is to find the information needed to solve problems. Sometimes it takes a few minutes or a little longer to solve a problem, sometimes it takes a long time, decades or even centuries. From the reality of teaching, students' cognitive process mostly belongs to the former, especially in classroom education. In a very short time, the process of understanding several objects should be completed, so teachers should guide students to think actively, explore the best time and choose the best knowledge media. For example, when discussing the stability of colloid, the teacher asked why the prepared colloid did not precipitate. On the basis of students' reading and discussion, playing audio-visual video of Fe(OH)3 colloid, students can clearly see the red micelle floating up and down near the cathode, and the whole process of preparation, purification and electrophoresis of Fe(OH)3 can be seen in only five minutes, so that students can quickly draw the conclusion that the colloid is stable, one is the mutual repulsion of charged colloidal particles, and the other is the diffusion of Brownian motion. The completion of this cognitive result is actually a reflection of the essential regularity of the objective object. It is the result of abstracting and summarizing the facts seen.
3. Training of reasoning ability
? Inference is a thinking form that derives a new judgment from one or several known judgments. Can be divided into inductive reasoning and deductive reasoning. Inductive reasoning is from special to general reasoning, that is, from individual special facts to general conclusions. For example, conductors, from copper, iron, aluminum, gold and silver, all metals are conductive, which is inductive reasoning. Deductive reasoning is from general to special, that is, from general principles to individual special cases. For example, the conclusion that "sodium has strong metal activity" is deduced from two judgments: "alkali metal element has strong metal activity" and "sodium is an alkali metal element". When learning elements and compounds, we can often infer the main chemical properties of other elements in the same family after learning the representative elements of a certain group of elements. It is deductive reasoning. In chemistry teaching, students are often required to summarize and reason what they have learned, so as to improve their reasoning ability.
Fourth, cultivate students' active learning.
Modern knowledge is updating at lightning speed, and no one can learn all the knowledge. Therefore, only by learning to learn, "it is better to teach people to fish than to teach them to fish", can we continuously enrich our knowledge in the future. The foothold of our teaching ultimately lies in making learning autonomous. "Teaching is to not teach, and learning is to learn." In classroom teaching, we should pay attention to cultivating students' learning skills and methods.
Let students take the initiative to learn, encourage students to actively participate in the teaching process, rather than passively form the connection between stimulus and response, and remind themselves that they are the masters of learning. Only by actively learning, actively obtaining information and actively thinking can we learn knowledge well and promote the development of thinking.
In the teaching process, it is only through the guidance of teachers that students' dominant position can be reflected. This is particularly prominent and important in experimental teaching, guiding students to learn to observe, think and operate, and encouraging students and teachers to evaluate and learn from each other.
Confucius said that "learning without virtue is useless, and thinking without learning is dangerous." The teaching process is also a process of guiding students to think. Through three years' thinking training, students can solve research topics independently and creatively, deepen their innovative consciousness and further develop their thinking ability.