First, explore the meaning and characteristics of learning
1. The meaning of inquiry learning
Inquiry learning is an important way for students to learn chemistry, and it is also an important way to cultivate students' inquiry consciousness and improve their inquiry ability. Inquiry learning refers to a kind of learning in which students actively acquire knowledge, apply knowledge, solve problems and form opinions in a way similar to scientific research under the guidance of teachers. This kind of learning does not indulge in pure chemical knowledge, nor does it directly give conclusions. Instead, it enables students to acquire learning ability, master learning methods and learn to learn in theoretical study, historical materials reading, problem discussion, experimental operation and subject research, so that ideological quality, moral level, scientific spirit, practical ability, psychological quality and aesthetic emotion can be harmoniously unified and comprehensively improved.
2. The characteristics of inquiry learning
2. 1 Inquiry learning is an activity aimed at some "problems". Therefore, it is of great significance to find and correctly express the chemistry-related problems to be solved for enhancing the purpose and pertinence of inquiry learning.
2.2 Inquiry learning is an activity combining logic with imagination. In the process of experimental exploration, we need to guess and make scientific assumptions, and we need to verify and test the assumptions through practice. Therefore, to carry out inquiry learning activities requires students not only to have certain logical thinking ability, but also to have certain imagination ability and dare to guess and assume. This plays an important role in cultivating students' innovative spirit and practical ability.
2.3 Inquiry learning is an activity based on scientific evidence. In this activity, we make predictions and inferences by obtaining and analyzing evidence, and make reasonable explanations to draw conclusions.
Second, the general steps to carry out inquiry learning activities in chemistry classroom
Generally speaking, the basic process of inquiry learning is as follows:
1. Ask questions
Educator clay? p？ Bedford said: "If you teach him to learn by stimulating curiosity, he will continue to learn all his life." Problems are the source of opening and developing thinking, so when students are curious about natural phenomena, social phenomena and experimental phenomena, they should be inspired and encouraged to ask questions.
The questions raised should have inquiry value, that is, to meet the needs of students in chemistry teaching and develop their scientific inquiry ability. The difficulty lies in the appropriateness of the topic, which is too easy for students to solve without thinking; If the topic is too difficult, students can't work it out no matter how hard they think. Such a question is of little value to explore. Therefore, the value of inquiry must be judged from the actual situation of students. For example, in the study of benzene, an important hydrocarbon in oil and coal [1], after introducing the molecular formula of benzene through chemical history, we can be curious: what is the structure of benzene? How to design experiments to verify?
Establish a hypothesis
Collect relevant information, connect existing chemical knowledge with problems, and try to put forward testable hypotheses. The hypothesis put forward must be logical, and the feasibility of experimental inspection should also be considered. For students who have been studying passively for a long time, it is unrealistic to let them have certain guessing and assuming ability immediately. Therefore, in teaching, on the one hand, teachers should cultivate students' guessing and hypothesis ability in a planned way, so that students can gradually change the habit of passive learning through a period of study and experience; On the other hand, we should also pay attention to creating lively teaching scenes, which will naturally stimulate students' imagination in the atmosphere of inquiry. At the same time, we should also affirm and appreciate students' ability to guess and assume, and enhance students' enthusiasm for actively and boldly proposing guesses and assumptions. For example, the molecular formula of benzene is C6H6, which has eight fewer hydrogens than alkanes. Students speculate that benzene may contain carbon-carbon double bonds or carbon-carbon triple bonds.
3. Design the experimental scheme
According to the purpose and conditions of exploration, design a suitable experimental scheme. The design of the experimental scheme should be practical, and the general requirements are simple operation, obvious phenomenon, safety, reliability and environmental protection. This process is difficult for students. We should fully consider the selection of reagents, experimental conditions, experimental operations and equipment, which can be solved through group discussion. For example, in the experiment to determine whether the structure of benzene contains carbon-carbon double bonds or carbon-carbon triple bonds, students combine the properties of ethylene just discussed and compare the carbon-carbon double bonds, suggesting that acidic potassium permanganate or bromine water can be used for testing, while some students take the addition reaction of ethylene and hydrogen as an analogy and propose to use the reaction with hydrogen for testing. Students who are going to design the reaction between benzene and hydrogen should design a hydrogen generator, a reaction device with benzene and a tail gas treatment device. The Kekule molecular formula of benzene is that single bonds and double bonds alternate. In the process of making assumptions, students may encounter individual knowledge points that have not yet been learned, which can be given in the form of "knowledge support". For example, in the experimental design of "Discussing the Redox of Iron and Its Compounds", teachers can provide commonly used oxidants and reductants to help students choose experimental drugs and design experimental schemes.
4. Exchange and evaluation of experimental programs
Many experimental schemes may be designed for the same experimental problem, so it is necessary to choose them. This step can be carried out through students' mutual evaluation and teachers' comments. In the process of discussion and communication, teachers should encourage students to use a variety of evidence to demonstrate their own plans, guide students to listen to other people's design plans and other people's evaluation opinions on their own experimental plans, find advantages and existing problems through reflection and self-evaluation, and put forward further improvement and perfection plans. This is actually a process in which students learn together. For example, in the experimental design of benzene, the feasibility of the reaction between benzene and hydrogen should be considered, and heating, pressure and catalyst (compared with ethylene) may be needed, so that students can compare the operability of these schemes themselves and get the best scheme.
5. Implement the experimental scheme
Experiment with relevant reagents and instruments to obtain experimental facts and evidence. In the process of experiment, it is necessary to design a table in advance and record the experiment situation at any time, which has high requirements for the correct use and storage of drugs, the correct connection of experimental devices and the accurate control of experimental conditions. The implementation of more complex experimental schemes, such as the discussion on the laboratory preparation method of chlorine gas, can be carried out in the form of group experiments, with 2-4 students cooperating with each other and teachers guiding at any time to ensure the smooth progress of the experiment (Cl2 is toxic, and effective measures such as tail gas absorption and conduction in the fume hood should be fully considered when designing the experiment).
6. Conclusion and evaluation
The conclusion is a summative judgment based on certain facts and evidence. Use language, words, charts, models and other ways to express the process and results of inquiry, exchange their own inquiry results, and comment with classmates. For the experimental situation, students should be organized to exchange experimental experience and summarize the experimental class. Teachers should judge the problems and experimental results in the experiment in time, analyze the success or failure of the experiment and its reasons, affirm students' achievements, encourage students to continue their exploration, and encourage more students to participate in the exploration of chemical experiments through the display of students' experimental results.