Biological science experiment is a practical activity aimed at understanding the essence and law of life movement. It is not a blind behavior, but a practical activity to change reality under the guidance of reason. In the process of every experiment, from the generation of experimental ideas to the design of experimental schemes, from the analysis of experimental results to the completion of experimental reports, every step has thinking activities, and every step is the result of thinking. Therefore, biological science experiments are conducive to bringing students into the situation of finding problems and enabling students to exercise their thinking ability of analyzing and solving experimental problems. Scientific thinking ability is an important aspect of scientific quality, and the cultivation of scientific quality is an important content of all-round quality education. This paper expounds some views on cultivating students' thinking ability in junior high school biology experiment. 1. Stimulating students' enthusiasm and interest in thinking is the trigger of thinking activities, and the need for knowledge is the basis of learning motivation. When students are interested in a problem, they will actively think about it. However, what is simply caused by the "charm" on the surface of "experiment" is only direct interest, and it will not last long without the attraction of deeper connotation. In order to keep students' lasting interest, we must be good at "creating" various incentives. For example, from the production practice and students' life, the experimental topics are drawn out, the purpose and significance of the experiment are constantly clarified, and interesting and thoughtful questions are constantly raised to arouse students' thinking, and so on. Through these means, students' direct interest can develop into indirect interest in time. Thinking is always carried out in the process of observing and solving problems. When a person has the need to overcome difficulties or understand problems, his thinking becomes active. Practice has proved that consciously creating situations to find problems is a good way to guide students to think positively. We should be good at using the questions in the columns of "observation and thinking" and "discussion" in practical experiments, and skillfully guide and mobilize the enthusiasm of students' thinking with enlightening questions in tutoring experimental teaching. Second, to help students master the basic process of scientific research, the primary problem of scientific thinking method is to clarify the basic process of scientific research, that is, the procedure of solving problems. For example, the experimental design idea of "observing the activities of rats and women". First of all, find problems through observation. Why is it easy to find rat girl under flowerpots and stones? What are the characteristics of these places? Secondly, put forward assumptions (boldly guess and explain the problems found). 1. The activities of rats and women may be related to the lighting conditions. 2. The activities of the rat girl may also be related to external factors such as moisture, and so on. The third step is to design an experiment to verify the hypothesis. At this stage, objectives, tasks, methods, materials, devices, etc. The result of the experiment is determined according to the hypothesis. So the theoretical basis of the experiment is mainly hypothesis (of course, it also depends on the students' mastery of relevant scientific knowledge). 1. First of all, check whether "light" has any influence on the activities of rat and girl. 2. In order to eliminate the interference of irrelevant variables, highlight independent variables and find out the causal relationship between independent variables and dependent variables, it is necessary to create a place with the same conditions except "light" and only light and shade. Put a certain number of female rats into it and observe the distribution of female rats in the light and shade. The fourth step is to analyze and discuss the experimental results, draw a conclusion and verify the authenticity of the hypothesis. Through the "mouse-girl experiment", help students feel and understand the basic process of scientific research: question → hypothesis → experiment → conclusion. Almost all junior high school biology experiments reflect this idea, so I won't go into details here. What needs to be clarified is that the scientific "hypothesis" is by no means groundless, but has scientific basis. This basis comes from the existing knowledge in the mind, or from the research results of others, or from the observation of objective reality. For example, the hypothesis put forward in the experiment of "digestion" is that "the cell membrane can only penetrate small molecular substances, and the macromolecular substances in food must become small molecular substances before they can penetrate the cell membrane." The theoretical basis of this hypothesis is as follows: ① Both humans and animals are made up of cells; ② Living cells need to absorb nutrients from the outside; (3) nutrients enter cells through cell membranes; ④ The nutrition of human and animals comes from food; ⑤ There are macromolecular substances in food nutrition. Through biological experiments, students can understand the basic process of scientific research. After repeated training, this thinking procedure can be internalized into students' thinking habits. Thirdly, the training of students' thinking operation skills includes several steps such as analysis, synthesis, comparison, abstraction and generalization. In order to realize the understanding of the nature and law of a life phenomenon in biological experiments, a series of thinking operations are needed on the perceptual materials in the experiments. First of all, it is to analyze what to study. According to the viewpoint of system theory, any living body or life phenomenon is an open and orderly whole composed of parts, levels and elements. For such a whole, it is impossible to swallow it and study it. Only by decomposing it can we study it part by part, go deep into it and discover its essence. The process of dividing the whole into parts in your mind, one by one, is analysis. For example, when studying the "external conditions affecting the activities of rats and girls", we should first decompose the "external conditions" into single factors such as light, water and chemical substances, and then examine the relationship with the activities of rats and girls one by one; When studying "photosynthesis", it is also decomposed into raw materials, conditions and products, and each part is composed of secondary components. In order to facilitate the study, a deeper decomposition is needed. All scientific experiments are inseparable from analysis. Synthesis, in mind, combines all parts of life, all aspects and attributes of life phenomena to form an overall understanding of life and life phenomena, which is synthesis. For example, after understanding the structure of cell membrane, cytoplasm, organelle, nucleus, etc. And then combine them to form a complete concept of living cells. Analysis and synthesis are antagonistic, complementary and closely related relations of unity of opposites. They are the basis of thinking activities. Comparison is to compare the structure, function and some properties of various parts of biology and determine their similarities and differences. This will lay a foundation for further understanding the nature and laws of life and for abstraction and generalization. For example, compare the similarities and differences in morphology, structure and function of various cells, compare the structures of various seeds, and compare the effects of amylase on starch under different conditions. , are the process of comparison. Abstract generalization is to find out the essential attributes of * * * in various organisms or various life phenomena, or to find out the causal relationship between structures, functions and structures, and between organisms and environmental conditions, while leaving aside secondary, non-essential attributes and non-causal accidental connections. Moreover, we must combine abstract essential attributes to form concepts and judgments, so as to realize the nature and laws of biological phenomena. For example, after studying all kinds of flowers in plants, in the absence of secondary attributes such as color and shape, the two most essential characteristics of "stamen" and "sexual reproduction" are extracted, forming a general concept of flowers, which is an abstraction and generalization of flowers. Analysis, synthesis, comparison, abstraction and generalization are closely combined with participating in the same thinking activity. Generally speaking, analysis and comparison are the basis of abstract generalization, and abstract generalization is the core of thinking. Only through abstraction and generalization can we understand the essence and development law of things, form concepts and principles, and thus achieve a rational understanding of things. Fourthly, cultivating the logic of students' thinking mainly refers to the ability to correctly use concepts, judgments and reasoning to think and express thinking results. During the experiment, students get a lot of concrete and intuitive perceptual materials through observation, and through thinking about these materials, they abstract and summarize the essential attributes and inevitable connections of various life phenomena, and then express or store them in the form of concepts, judgments and reasoning. Various basic concepts, laws and principles in biology are concrete manifestations of concepts, judgments and reasoning. These constitute the knowledge system of biology. The basic concepts and concept system of biology are the basis of biological science knowledge, so we must attach importance to the teaching of basic concepts. But let students acquire these concepts through "labor", form these concepts through experiments, observation and thinking, and express them in scientific language. Insisting on letting students define concepts and deduce experimental conclusions is actually to train students' logical thinking ability. The common reasoning methods in biological experiments mainly include inductive reasoning and deductive reasoning. This creates favorable conditions for cultivating students' reasoning ability. Induction is a form of thinking that induces universal principles from individual cases. Generally divided into complete induction, simple enumeration and causal induction. Simple enumeration is a common method in biological experiments in middle schools. For example, one female mouse likes darkness and is afraid of light, while two female mice like darkness and are afraid of light ... From the fact that most female mice like darkness and are afraid of light, it is concluded that all female mice like darkness and are afraid of light. For another example, many biological concepts such as flowers and seeds are the result of simple enumeration and inductive reasoning. Causal induction can take many forms, such as seeking common ground, seeking differences, and residual method. These methods are all applied to designing biological experiments. For example, the experiment of photosynthesis applied the method of seeking difference. The method of seeking difference is to study the causal relationship between phenomenon (a) and condition (a). If a phenomenon also appears when A exists, but A does not appear when A does not exist, it can be concluded that A and A have a causal relationship. The relationship between photosynthesis and "illumination" conditions is as follows: processing light (a) other conditions (b) photosynthesis (a) ① illumination √√②shading ××× Conclusion The deductive reasoning about photosynthesis related to illumination conditions is from general principles to special cases. It has three types, of which "syllogism" is the most widely used. For example, starch, one of the products of photosynthesis, is applied to the thinking form of "syllogism". The major premise is that all substances that turn blue when exposed to iodine are starch, and the minor premise is that if one of the photosynthetic products turns blue when exposed to iodine.