Chemical experiment report

Chemistry is an experimental-based discipline. Many of the laws and laws of chemistry are found in experiments. At the same time, the application and evaluation of chemical theory also depends on the exploration and testing of experiments. Although in recent times and even in modern times, the rapid advancement of chemistry has produced a variety of new research methods, but experimental methods are still an indispensable research tool for chemistry. The new curriculum reform takes scientific inquiry as a breakthrough. Scientific inquiry is not only an important learning method, but also an important content of the middle school chemistry curriculum. It has an irreplaceable role in developing students' scientific literacy. And chemical experiments are an important form of scientific inquiry.

Learning chemistry by chemical experiment is not only in line with the characteristics of chemistry, but also in line with the understanding characteristics of students' learning chemistry. It is the basic means of implementing quality education in chemistry teaching. The new curriculum standards encourage students to conduct independent or collaborative chemistry experiments. Through chemistry experiments, students can stimulate their interest in learning, help students to form chemical concepts, understand basic chemistry theories, master chemistry knowledge and skills, cultivate students' scientific attitudes and values, and help students develop their thinking skills and training experimental skills. Improve the scientific literacy of students in an all-round way.

I. Understanding of middle school chemistry experiments under the new curriculum standards

The "General High School Chemistry Curriculum Standards" clarifies the basic philosophy of the high school chemistry curriculum: based on the needs of students to adapt to modern life and future development, focusing on improving the scientific literacy of citizens in the 21st century, building "knowledge and skills", "process and method" The high school chemistry curriculum target system that combines “emotional attitudes and values”. “Knowledge and Skills” is the “double base” of the past; “Process and Method” is to let students master the method of learning and learn to learn; “Emotional Attitudes and Values” is the embodiment of humanistic care. Therefore, the core of the new curriculum concept is “to enable students to develop in the process of knowledge exploration in terms of knowledge, learning, and humanities.” Article 5 emphasizes: “A variety of inquiry activities based on chemical experiments. To enable students to experience the process of scientific research, stimulate interest in learning chemistry, strengthen the awareness of scientific inquiry, promote the transformation of learning styles, and cultivate students' innovative spirit and practical ability." [1] The high school chemistry course consists of 2 compulsory modules and The six elective modules are composed of “Chemical Experiments” as an independent module that is different from the previous textbooks and highlights its important position.

The "Basic Education Curriculum Reform Outline" issued by the Ministry of Education in 2001 pointed out the direction for the chemistry curriculum reform. According to the new teaching concept and the resulting new curriculum standards, it is not difficult to find new courses in experimental teaching. There are several major changes:

1. From focusing on cultivating experimental operation ability to cultivating experimental thinking ability and cultivating experimental operation ability, changing the past design design experiment of “teaching” into “study” design experiment, making the experiment better match the active learning of students and breaking In the past, the design of teacher monopoly experiment program helped teachers to guide students to participate in the design of experimental programs. This is the so-called investigation of chemical experiments [2]. The key to changing the status quo of the chemical experiment "photographing the medicine" is to strengthen the inquiry design of chemical experiments, which is of great significance for better exerting the functions of chemical experiments and promoting the active and comprehensive development of students' scientific literacy. For example, in Exploratory 1 "Exploration of whether iron can react with water vapor", the textbook provides the necessary instruments and medicines for the experiment, and allows students to design experimental protocols; on the other hand, it provides an experimental program for students. Refer to and try to use the program to conduct experiments, and finally let the students summarize the exchange of inquiry activities. Such experimental teaching, while guiding students to learn design experiments, also exercises the hands-on ability of students to carry out experimental inquiry.

In addition, the new curriculum standard no longer rigidly divides the demonstration experiment and the student experiment, but provides space for the creativity of the teacher and the initiative of the student. Teachers create learning scenarios through experiments, providing students with observable chemical phenomena and experimental operations. Their activities are directed at students' self-observation, analysis and thinking, exchange and discussion, and experimental research. They are not simple performances or demonstrations of teachers. From this perspective, it is the student's activity, just like the student experiment. In the new curriculum standard, students are also encouraged to carry out chemical experiment research to realize the "two-legged walking" transition from the spontaneous research of "single soldier combat" to the study of masses and team research. This article is organized by the first · Fan Wenwang, the copyright belongs to the original author, the original source all.../

2. From the emphasis on theory to the combination of theory and practice, pay more attention to the connection between chemical experiment and life and technology, pay attention to solving practical problems by means of experimental inquiry; and transform students' in-class learning into in-class and extra-curricular combination. The mode is more suitable for the needs of open learning, which is the so-called life of chemical experiments [2].

The new curriculum standard “focuses on the students' existing experience and enables them to learn chemistry in a familiar life situation” to help students “know chemistry from the perspective of science, technology and society”, and to understand chemistry from a combination of history and reality. . In addition, the new curriculum standard also lists a number of learning context materials to choose from, which helps teachers to implement the teaching requirements of “close to life, connect with reality” and deepen students' understanding of the concept of “science – technology – society”. Enhance students' sense of social responsibility, and inspire teachers to continuously absorb fresh information from social life and new technological development. Students gradually understand the important role of chemistry in promoting sustainable development of society. Explaining and solving daily life and social problems through chemical experiments is of great significance and value for expanding the functions of chemical experiments and improving students' scientific literacy. The content of the chemistry experiment is selected from many chemical phenomena in daily life and social life. The experimental drugs are taken from the common chemical substances around the students, so that students can have a sense of intimacy, feel that the chemistry is not mysterious, and it is beneficial to us. To motivate students to learn and to stimulate their interest in experimental inquiry. There are many such experimental materials in the textbooks of the new course. Such as the "Use of materials in life to make a simple battery" experiment in Compulsory 2; "Reducing the vitamin C in fresh fruit" experiment in Elective 1; "Separate water-absorbing material with starch and simulated water retention test" in Elective 2; Elective 4 Experiment on the effect of temperature on the washing effect of enzyme washing powder; the experiment of "washing effect of homemade soap and soap" in Option 5; "Electrochemical oxygen demand in sewage by redox titration or electrochemical analysis" in Option 6 "Experiment and so on.
3. From the application of modern experimental methods to the appropriate application of modern experimental methods and instruments, attach importance to the transformation of middle school experiments to modernization, which is the so-called modernization of chemical experiments [2].

The invention and use of modern scientific methods of chemical experiments are inseparable from human exploration of the composition and structure of matter. The identification of the chemical composition of a substance requires qualitative analysis. The determination of the content of each component of the substance requires quantitative analysis. Determining the structure of the substance requires structural analysis. The new high school chemistry curriculum has greatly improved the quantification of chemical analysis methods and the modernization of experimental methods compared with previous chemistry courses. Four categories of instruments or methods for modern instrumental analysis were introduced in the new high school chemistry curriculum. For example, in Elective 5, “Measurement of relative molecular mass by mass spectrometry”, “Identification of molecular structure by infrared spectroscopy, nuclear magnetic resonance spectroscopy, etc.”; Experiment 6 “Testing halogens in halogenated alkane by chemical method or infrared spectroscopy” in Experiment 6 , "Using Neutralization Titration or Gas Chromatography to Determine the Content of Acetic Acid in Acetic Acid" Experiment. It is worth noting that the study of these modern experimental analytical instruments and methods does not require students to master their specific principles and application techniques. The degree of requirements required by different experimental techniques is different. Some are only of an introductory nature. They only require students to master their most basic principles and achieve the goal of expanding their scientific horizons.

4. Emphasis on the embodiment of green chemistry ideas and sustainable development concepts in experiments. This is the so-called greening of chemical experiments [2]. The new high school chemistry curriculum is designed with a focus on “reflecting green chemistry ideas”. For example, in Elective 6, the concept of “formation of green chemistry” is taken as an important goal; “the awareness of green chemistry and the formation of environmental protection” is taken as a “content standard” alone; 'The production of ideas for chemical products' as a learning activity in the "Activity and Inquiry Advice".

Second, the issues to be paid attention to when carrying out chemistry experiment teaching

Under the new curriculum standards, chemistry experiment teaching has a more prominent role and significance. Therefore, doing a good job of experimental teaching is an important teaching content in chemistry teaching. So, what issues should be paid attention to during the course of conducting chemical experiment teaching? The author believes that it can be considered from the following aspects:

Strengthening ideological understanding and attaching importance to the function of experimental education

Stimulating interest in learning, experiencing scientific inquiry, training feasible methods, learning chemistry knowledge, and learning to unite and collaborate are the main educational functions of chemistry experiments. In this regard, teachers must first have a profound ideological understanding, and at the same time, they must play a good role in these chemistry experiment education functions through specific teaching practices.

Specifically, in the design and selection of experimental content, teachers need to pay attention to the students' existing experience and the social life experience that they will experience, in order to stimulate students to learn chemistry interests and help students understand the close relationship between chemistry and human life. The chemistry-related social problems faced by human beings foster students' sense of social responsibility, participation, and decision-making. Through chemistry experiment teaching, students can learn chemistry knowledge. In the process of learning, they will get a lot of perceptual knowledge, transform sensible cognition into rational cognition, and use existing knowledge and related materials to solve problems. At the same time, learning to unite and cooperate is the requirement of the quality of talents caused by the increasingly perfect and meticulous division of labor. In the choice of experimental content, we should pay attention to the selection of some experimental explorations that can be completed through group collaboration, so that students can explore in experiments. In the process, according to the requirements, work division and cooperation, complete the experiment together, learn to cooperate and share in the experimental inquiry.

The new course in the first chapter of Compulsory 1 "From Experimental Chemistry" has made it clear that "chemistry is an experimental-based natural science" and emphasizes the importance of mastering experimental methods. We can make good use of the first section of the "Basic Methods of Chemical Experiments" textbook, first to educate students on the characteristics of chemistry and chemistry learning methods, including experimental safety education and experimental normative education. Experimental safety education can be considered and communicated by students in groups and then summarized by students, so that students realize that the operation of chemical experiments should be standardized, and safety measures should be carefully checked to ensure the safety and success of the experiment. Then, using the group to do the experiment can be a group of two, with a rough division of labor, basic responsibilities, and close cooperation to complete the "purification of crude salt" experiment. After the students complete the experiment, they should sum up and evaluate each other. The teacher finally reviews the students' performance in light of their observations and praises some groups or individuals. Through such experimental teaching, the students' experimental safety awareness has been cultivated, and the students' sense of unity and cooperation has been established.

Improve the ability to work and pay attention to the cultivation of students' experimental skills

The basis for conducting chemical experiments is that the experimenter must have a certain understanding of the basic methods and skills of chemical experiments. The curriculum objectives of the new curriculum standards will include “acquiring basic knowledge and basic skills in chemical experiments, learning experimental research methods, and designing and completing some chemical experiments” as one of the goals of “knowledge and skills”. In the new course, a large number of students' experimental inquiry content is added. Every experiment in the experimental inquiry must be done by the students themselves. Therefore, improving the students' experimental ability is the basis for completing the good chemical experiment teaching. At the same time, we must attach great importance to the ability of students to solve problems, especially observation, experiment, hypothesis, reasoning, collecting data, analyzing data, processing data, and so on. It is necessary to attach importance to the development of students' practical spirit and innovative ability through the development of students' agility, flexibility, profoundness, originality and criticality.

It is worth noting that, due to the limitations of various conditions, the textbooks are often written with more experiments and less students. If the teacher is teaching in accordance with the "teacher demonstration experiment → student observation experiment → teacher guides the students to draw conclusions → examples → classroom Training → post-class consolidation exercises, the effect is that students will try and not develop. Therefore, teachers should create conditions, flexibly handle textbooks according to actual conditions, and try to demonstrate studentization as much as possible, so that each student has a chance to do so. The student's operation process is: according to the problem to be solved → design experimental principle → select experimental equipment → hands-on experiment → record phenomenon and data → process data to draw conclusions.

For example, in the first section of the first chapter of Compulsory 1 "Basic Methods of Chemistry Experiments", the textbooks do not have a hard distinction between demonstration experiments and student experiments. In order to better improve students' experimental ability, teachers are encouraged to use experiments while speaking. teaching methods. This is conducive to students mastering experimental skills, training observation, thinking, independent operation and other abilities, easy to get a sense of success. It is recommended that experiment 1 "purification of crude salt", experiment 2 "test of sulfate ion" as a side-by-side student experiment, experiment 3 "laboratory preparation of distilled water" as a demonstration experiment, experiment 4 "extraction and liquid separation" is required The student completes the experiment under the guidance or demonstration of the teacher.

Develop awareness of problems and improve students' ability to solve problems

Enhancing the ability to develop students' problem awareness and turning problems into topics is a prerequisite for improving students' design and problem-solving skills. Problem consciousness refers to the psychological state of suspicion, anxiety, and inquiry that students are aware of in their activities. This state of mind drives students to think positively and constantly raise and solve problems. Psychological research shows that the existence of problems is the starting point of thinking, and the thinking without problems is superficial thinking and passive thinking. In the teaching of chemistry experiment, the problems that can be used for experimental inquiry may come from natural phenomena, social life and production practice, or from the process of learning, and may also come from the problem situation designed by the teacher. No matter what the situation, always Let students have the desire and desire to find and solve problems. If some of the validated experiments in the textbook are changed to exploratory experiments, students can be brought into the context of scientific inquiry, thus continuously enhancing their awareness and ability to find problems and solve problems.

For example, for the "Fe2 preparation and properties" experiment in Compulsory 1, the teacher first explained the color, state and solubility of Fe2, and then demonstrated the reaction of the new FeSO4 with NaOH solution. As a result, the student failed to observe the white flocculent precipitate. And what I saw was a gray-green precipitate. This phenomenon will immediately attract the attention of the students, teachers should prompt students to ask questions: 1 Why use the new FeSO4 solution? 2 Why insert the dropper into the bottom of the solution in the test tube and slowly squeeze out the NaOH solution? 3 What kind of substance is dissolved in the NaOH solution for a long time? When students realized that FeSO4 and Fe2 were easily oxidized by oxygen in the air, they changed a bottle of boiled NaOH solution to remove dissolved oxygen, and then experimented, first obtained a white precipitate, but after a while it changed. It turns gray and then turns reddish brown, which raises questions for students. The teacher further guided the discussion: What method can be used to slow the rate of oxidation of Fe2 produced? After a series of reflections, discussions, comparisons, and finally selected a few drops of benzene as a protective layer on the surface of the new FeSO4, the dropper was inserted into the bottom of the test tube; the boiled NaOH solution was added dropwise to finally obtain a white Fe2 precipitate. And kept it for a long time. Through similar experimental teaching, students will eventually become aware of problems and solve problems and become a need.

Experiments are an important way to develop students' ability to solve problems. Scientific discovery activities such as problem discovery and formation, experimental design, operation, observation, thinking, expression and communication in experimental teaching can effectively cultivate students' experimental consciousness, subject discovery ability, experimental design ability, experimental observation ability and experimental operation ability. It can effectively cultivate students' thinking habits and thinking ability, which is difficult to replace with other forms of activities.

The new textbook has created many hands-on opportunities for students. How can we mobilize the enthusiasm of students? In the course of teaching the new course Gao Yi chemistry, I tried to improve the students' experimental ability through different teaching activities, and accumulated a little experience to share with you. I organized students to conduct extra-curricular experiment teaching with the help of a student's supplementary book "Chemical Activities and Exploration". The book's activity projects are drawn from the typical textbooks and designed as event cards. Each card contains six columns: problem thinking, activity inquiry purpose, activity research supplies, activity inquiry content, communication and discussion, harvest and experience. Here are some specific practices: Before starting the activity, let the whole class voluntarily divide into 8 groups and implement the team leader responsibility system. A group of experiments is conducted every week, and each group is free to choose a topic. The content of the experiment can be selected from 30 activity items in the activity card. The team leader is responsible for organizing and completing the experiment in the spare time, including experiment preparation, division of labor, activity record and activity evaluation. The entire group's experimental activities were completed in one week, and the team leader used the 15 minutes of the next week's chemistry class to "close the case." Accumulate the experimental reports of different groups every week, and show them regularly, so that everyone can vote for the best cooperation group. In the course of each group of activities, teachers will also participate in it. Where the group is doing well, it should be praised in a timely manner. It is necessary to promptly dial out and clear the existing problems, and play a guiding role. Evaluation and inclusion in the calculation of the credit system. Through these experimental activities, it is conducive to cultivating the ideological quality of students seeking truth from facts, respecting science and being brave to explore; cultivating students' scientific attitude of unity, cooperation and truth-seeking, and also stimulating students' interest in studying chemistry. In the experimental teaching, students are not only required to take the experiment seriously. As a teacher, they should take each experiment seriously. Guide the students to pay attention to the experimental process through the experiment, highlight the students' main position in the experimental teaching, enhance the exploratory nature of the experiment, and cultivate the students' science. Exploring and experimental design and evaluation capabilities.

All in all, chemistry experiment is an important part of the content of chemistry teaching in middle school. The reform of experimental teaching of new curriculum plays an important role in the reform of high school chemistry curriculum. Under the guidance of the new teaching philosophy, the vast number of chemistry teachers should study and study new courses conscientiously and meticulously, raise awareness and clarify goals. Learning around the experiment is a full expression of the characteristics of middle school chemistry teaching. As long as the chemistry experiment teaching is truly implemented, it will have a positive effect on stimulating students' interest in learning chemistry, cultivating students' creative thinking, developing students' potential and developing students' personality. It also exerts a unique function for the path of quality education in chemistry education [3]. New ideas, new curriculum standards, and new textbooks urgently require the renewal of experimental teaching concepts. This is a challenge that prepares us to face this challenge.