The basic form of teaching design of chemistry inquiry experiment in middle school. Combined with teaching practice, it emphasizes the use of inquiry teaching to cultivate students' ability to ask, analyze and solve problems, and to cultivate students' ability to collect and process information, innovate and explore. This paper probes into the basic forms of teaching design of middle school chemistry inquiry experiment from the aspects of teaching content, teaching process, teaching media resources and teaching evaluation.
Specific methods can refer to the following specific cases:
Exploration of open experiment: exploration of reaction products of metal sodium and copper sulfate dilute solution
3. 1 introductory questions
Through the study of "alkali metal elements" and the teacher's classroom demonstration experiments, students have mastered the physical and chemical properties of sodium and understood the experimental phenomena and reaction products of sodium and water. On this basis, teachers guide students to think about what products will be obtained when sodium with very active properties reacts with copper sulfate solution. According to the knowledge that the metal activity of sodium is stronger than that of copper, some students do not hesitate to task: sodium can replace copper in copper sulfate; Some students also have questions: Does sodium react with water or replace copper first? At this time, through the guidance of teachers, a good "focus" of inquiry is formed.
3.2 conjecture and hypothesis
Teachers can organize students to discuss in groups and put forward their own ideas on the problem. The class's guesses and assumptions are mainly divided into two categories. Firstly, sodium replaces copper in copper sulfate to generate red precipitate of elemental copper and sodium sulfate solution; Second, sodium reacts with water to generate sodium hydroxide and hydrogen, and then sodium hydroxide reacts with copper sulfate to generate blue copper hydroxide precipitate.
3.3 put forward the experimental scheme
Because of the openness of the inquiry topic, each group of students put forward various experimental schemes. To sum up, the main parts are basically the same: take a piece of metallic sodium the size of mung bean, wash kerosene with filter paper, put it into a large test tube, and add copper sulfate solution into the large test tube with a separatory funnel. Some experimental groups added other experimental equipment to verify that hydrogen was produced in the experiment. There are two representative types: one is to introduce gas into a hot copper oxide test tube with a catheter. The second method is to place a balloon at the top of the separatory funnel.
3.4 experimental inquiry, experimental phenomena
Through grouping experiments, students mainly get the following realization images.
project
number of people
Conjectures and assumptions
Predicting experimental phenomena
Experimental phenomenon
9 groups (32 people)
Production of copper hydroxide
Blue flocculent precipitate is produced and hydrogen gas is released.
Blue flocculent precipitate is produced and hydrogen gas is released.
The fourth group (16 people)
Production of copper hydroxide
Blue flocculent precipitate is produced and hydrogen gas is released.
The third group (12 people)
Substitute copper
Produce red copper oxide precipitate.
Blue flocculent precipitate is produced.
3.5 Explain communication
When the students finished the experimental exploration, they cooperated with each other and finally came to a conclusion. Sodium metal reacts with copper sulfate solution. Firstly, metallic sodium reacts with water in copper sulfate solution to generate sodium hydroxide and release hydrogen. Then, sodium hydroxide reacts with copper sulfate to generate blue copper hydroxide precipitate. In some experiments, blue copper hydroxide precipitates and the black solid is copper oxide. After exchange and discussion, the students think that the reaction between metal and water is a violent exothermic reaction, and the released heat can decompose part of copper hydroxide to produce black oxidized solid. So why does sodium react with water first? For this problem, two students put forward in the experimental report that because the density of water molecules in copper sulfate solution is higher than that of copper ions, it is equivalent to generating hydrated copper sulfate, and copper ions are surrounded by water molecules, so sodium reacts with water first.
3.6 Teacher evaluation
Through exploratory experiments, most students have mastered the experimental process and phenomena, and can put forward a reasonable and firm principle of phenomenon occurrence. By consulting students' experimental reports, it is found that most students did not fill in the record column of group members, which shows that students' awareness of cooperative discussion is still weak and they are not good at recording. In the part of self-evaluation, the students wrote: "To tell the truth, I prefer experiments, and I prefer to find special situations from experiments to study. Of course, be careful when doing experiments. Many things in the experiment are irreparable, and the resulting losses are unnecessary "; "As long as the experimental operation is standardized and there is a certain knowledge base, you can cultivate your own experimental interest and find out the experimental methods"; "This experiment not only exercises our hands-on ability, but also allows us to draw conclusions through experiments, which can improve our interest. We have a strong experimental operation, a good knowledge base and are very interested in experiments. The experimental method needs to be further improved. I hope we can have more opportunities to do experiments "; "I think that in the experiment, our hands-on ability is poor. From the experimental results, my thinking ability is not comprehensive enough and my foundation is not solid enough; Through this experiment, we not only increased our extracurricular knowledge, but also made me experience the strictness of objective facts, and so on. The self-evaluation of students shows that all students are interested in the experiment, and it is suggested that more opportunities be provided in the future. Most students think that their knowledge base is good, and their evaluation of their experimental operations and methods is generally lower than that of teaching. In the evaluation part of the members of the same group, students' scores are mostly "very good or better", and there is no grade, and they are highly evaluated each other, which contradicts the self-evaluation part. Therefore, students did not establish a correct attitude towards mutual evaluation, and the evaluation was distorted.
4 conclusion
Looking back on the historical changes and vigorous development of inquiry experiment teaching today, we clearly realize the significance of inquiry experiment teaching in senior high school chemistry in the current chemical education and teaching reform. The basic process of implementing inquiry experiment teaching in senior high school chemistry teaching is deeply analyzed. We fully realize the important value of inquiry experimental teaching in cultivating students' experimental inquiry ability and spirit, experiencing the process of scientific inquiry, mastering the basic methods of scientific inquiry, giving full play to students' cooperative learning and team spirit, and forming a rigorous and meticulous scientific attitude of seeking truth from facts. From the perspective of epistemology, combined with cases, this paper expounds the epistemological functions of inquiry experiment teaching in raising chemistry teaching questions, understanding scientific inquiry process, providing students with chemical scientific knowledge, testing chemical theories and verifying chemical hypotheses.
Looking forward to the future, with the full implementation of the new curriculum reform, the research of inquiry experimental teaching will be gradually "refined" and the practice of inquiry experimental teaching will be more and more abundant. It will become one of the main means of chemistry teaching in senior high schools and a fertile ground for school-based curriculum development in senior high schools. With the development of economy, the instruments, equipment and conditions of chemical experiments are becoming more and more perfect. I believe that the prospect of inquiry experiment teaching in high school chemistry will be more and more beautiful.
Blue flocculent precipitate is produced, which is mixed with black solid to release hydrogen.