Chemistry is a subject based on experiments. In the past, chemical experiments were ignored in the process of chemistry teaching, and it was common for teachers to talk about experiments. With the in-depth implementation of the new curriculum reform, chemical experiments gradually attract people's attention. At present, the number of students in large classes cannot be accommodated by the laboratory; Teaching experiments in large classes, experimental instruments and drugs are far from meeting the needs of students' experiments. Many school experiment teachers can only use demonstration experiments instead of students' experiments, and barely complete the teaching task. Even some schools simply don't do experiments and only talk about theory; The weakness of rural teachers is also the bottleneck that affects the abnormal development of experimental teaching in rural middle schools. The relative lack of professional chemistry teachers makes the standardization and scientificity of experimental teaching very problematic. Due to the lack of teachers, most teachers spend too much time on experiments and research. Some schools in rural areas are relatively backward in management, and there are no specialized laboratory administrators. Most of the laboratory management is given to the logistics and general affairs teachers, who only play the role of keeping property, which brings great inconvenience to the experiment. Rural middle school students come from village-run primary schools in various villages, with uneven basic level, poor hands-on experimental ability, introverted personality and weak desire to express; These problems have seriously affected the development of chemistry experiment teaching in rural middle schools, so it is particularly important to find a solution to the existing problems in chemistry experiments in rural middle schools as soon as possible. This topic will study and explore the above problems and find ways to solve the difficulties in chemical experiment teaching in rural middle schools.
Second, the content of the study:
(1) Problems and countermeasures of relative shortage of pharmaceutical instruments in rural large classes;
(2) Problems and countermeasures of insufficient chemistry teachers and laboratory personnel in rural middle schools;
(3) Problems and countermeasures of poor practical ability of rural middle school students;
(4) Problems and countermeasures that some experiments cannot be demonstrated due to insufficient conditions or unobvious phenomena.
Third, the significance of this study.
The research on the problems and countermeasures in the chemical experiment teaching in rural middle schools is of far-reaching significance to the experimental teaching, students' ability training and ecological environment in rural middle schools.
(1) can effectively alleviate the problem that the current rural laboratory resources are insufficient and the normal experiment rate cannot be guaranteed. At present, the common problems in rural middle schools are: the average laboratory area is not up to standard, the equipment is poor, the number of instruments and drugs is insufficient, the laboratory management is not standardized, and the experimental funds are insufficient. These problems have been puzzling the chemical experiment teaching in rural middle schools for many years, which can not guarantee the normal opening rate of experimental courses and seriously affect the implementation of the new curriculum in rural areas. Through the research of experimental substitutes and the exploration of laboratory management, the prominent contradictions in chemistry experiments in rural middle schools can be alleviated to some extent. Let the chemistry experiment teaching in rural middle schools develop healthily and orderly.
(2) It can further cultivate students' experimental operation ability and thinking ability, as well as the ability to analyze and solve problems. Influenced by various aspects, rural students' hands-on ability is not strong, which hinders the implementation of the new curriculum in rural areas and makes rural middle school students synonymous with "high scores and low abilities". The reasons for the low experimental ability of middle school students in rural areas are as follows: first, there is a shortage of rural teachers and professional experimental teachers. Some teachers attach importance to theory and ignore experiments in the teaching process, and over time, students lack interest in experimental operation; Second, some rural students are introverted and have a weak desire to express themselves, and are unwilling to show off in front of teachers and classmates (mainly girls). Through the study of experimental substitutes, the author replaces experimental supplies with some daily necessities, which improves the enthusiasm of students to do experiments. In addition, some demonstration experiments have become students' grouping experiments, and the passive experiments originally told by teachers have become creative experiments under the guidance of teachers. Let students participate in the management of the laboratory. Driven by students, students' enthusiasm for experimental operation can be fully mobilized. Opening the laboratory regularly and irregularly can enable students to come to the laboratory immediately when they encounter problems in class and solve them in time through experiments, which can not only cultivate their experimental operation ability, but also cultivate their analytical ability. Guide students to actively start work and complete chemical manual production. While enjoying the fun of designing and making, students have a closer understanding of some experimental instruments, which has played a positive role in cultivating the experimental operation ability of rural middle school students.
(3) It is conducive to energy conservation and emission reduction and building a resource-saving society. Large class students will consume a lot of experimental supplies in chemical experiments, and at the same time, they will discharge a lot of waste liquid, waste gas and waste residue. It has certain pollution to the environment. Through the exploration and research of "conservation-oriented" chemical experiments, the author looks for cheap, environmental-friendly substitutes for instruments and drugs that turn waste into treasure. It greatly saves school expenses, uses less drugs and emits less harmful substances to the environment. It plays a positive role in saving chemicals, saving energy and reducing emissions, and has far-reaching significance in cultivating students' thrifty thinking, environmental awareness and love for nature.
Fourth, the theoretical (empirical) results of the research.
(1) Experience and achievements:
(1) In view of the relative shortage of pharmaceutical instruments in large classes in rural areas, a set of better solutions has been found.
At present, there is widespread teaching in large classes in rural middle schools, and the laboratory resources are relatively low, coupled with the shortage of funds in rural middle schools. Although the state has increased its investment in rural middle schools and equipped them with some necessary experimental equipment and drugs, which can meet the needs of teachers' demonstration experiments, the number of drugs needed by students' experiments is too large to fully meet the needs of students' experiments. However, according to the requirements of curriculum standards, teachers have to find ways to find some experimental substitutes to ensure the normal opening of students' experiments.
Through the teaching practice in recent years, the members of the project team found that the junior middle school chemistry experiment is qualitative, and some drugs can be replaced by daily necessities, which not only reduces the experimental cost, but also is easy to buy and will not delay the experimental time of students. For example, sodium chloride, which is commonly used in the laboratory to prepare brine, can be replaced by experiments, and limestone with carbon dioxide gas is completely unnecessary to buy. Limestone is the most important around the school where the author works. The teacher only needs to lead the students to pick up some stones rich in calcium carbonate and break them. Zinc particles commonly used in the laboratory, I often call on students to collect waste batteries, take their skins and cut them to replace zinc particles to prepare H2O2 solution of oxygen. If the laboratory is not enough, you can only get it from the nearest drugstore. Na2CO3 commonly used in laboratory is often replaced by edible soda ash.
(2) The concept of chemistry teachers in rural middle schools is backward, and there are a set of effective countermeasures for the shortage of laboratory staff.
With the implementation of the new curriculum reform in rural areas, the state has increased its investment in rural middle school teachers and school conditions. However, compared with cities, there are still obvious weak links in rural areas, teachers are still weak, and basic school facilities are still backward. Some schools don't have professional physics, chemistry and biology teachers, let alone specialized experimenters and laboratory managers. In this way, most chemistry teachers in rural middle schools still use chalk and blackboard instead of experiments. In the past, schools and teachers did not pay enough attention to experimental teaching, thinking that experimental teaching had no obvious effect on improving grades and was a waste of time. As a result, rural middle schools are far from urban students in cultivating students' experimental operation skills, which undoubtedly hinders the implementation of the new curriculum in rural areas. First of all, chemistry teachers should renew their educational concepts, study chemistry curriculum standards seriously, understand its essence, study the examination trend after the curriculum reform, grasp the significance of experimental teaching, change their teaching concepts, reform teaching methods, and truly implement experimental teaching. However, due to the change of chemistry teachers and the change of curriculum arrangement in various schools, I hope that the county can hold chemistry professional training every year, which can improve the professional quality of chemistry teachers, update teaching methods and better adapt to the requirements of the new chemistry curriculum reform.
In addition, most chemistry teachers also serve as class teachers and several classes, and also as laboratory administrators, experimenters and other roles. Most rural middle schools have 3-6 classes in the ninth grade, but there is only one chemistry laboratory, and there is no special chemistry experimenter. In the process of teaching, students should organize an experiment, teachers should be busy for several days, prepare all kinds of equipment and medicines needed by students' experiments, and then prepare experimental classes. After a few classes, I will be busy adding medicine, replenishing consumables and checking whether there is any equipment damage. After the experimental class of four or five classes is over, the teacher is still busy cleaning up the laboratory. Usually after an experiment, the teacher is exhausted. How to deal with the relationship between these roles, how to arrange teaching reasonably and provide a good experimental environment for students? I think we should innovate boldly, train laboratory assistants among students and train small experiment administrators. I start to find 2-3 responsible and hard-working classmates in each class at the beginning of the first semester of Grade 9 every year. Through some simple training, by the second half of the semester, these students in each class have basically been qualified for the work of laboratory personnel. Before and after each experiment, students can prepare experimental instruments and drugs according to the teacher's requirements. This not only helped the teachers a lot, but also greatly promoted their own study of chemistry. But also can drive the class to form a strong atmosphere of learning chemistry. This not only facilitates teachers, cultivates students' ability, but also stimulates students' strong interest in learning. Why not teachers?
(3) By improving the experiment, the demonstration was changed to students' grouping experiment, and the experimental steps were told by teachers in advance to students' designing experiments under the guidance of teachers, which solved the problem of poor practical ability of rural middle school students.
Students in rural middle schools have poor hands-on ability in chemical experiments. The author found through investigation that the reasons are as follows:
1, teachers attach too much importance to experiments, strictly demand students, and overemphasize the preciousness of experimental instruments, which will increase students' psychological burden and make many students cautious and timid when doing experiments, afraid of damaging instruments, and be criticized by teachers.
2. Some teachers overemphasize the toxic effects of reagents and drugs, which leads to students' fear, so they take an evasive attitude in the experiment.
3. Some experiments in the textbook have the characteristics of known operation process and known experimental results, and some have been demonstrated by teachers, which are easy to form repetitive and boring problems. Most of the experimental classes are crammed, that is, teachers and textbooks are designed. In order to ensure the normal progress of the experiment, the teachers are preparing more and more carefully, and the students just take medicine according to the prescription, far from independent thinking. As a result, many students have lost interest in experiments.
4. Some exploratory experiments, many students don't know the experimental links and want to start, but they can't.
Some students think that the chemistry experiment is too mysterious, so let's learn the theoretical knowledge first.
6. Some students are introverted and unwilling to show off in front of teachers and classmates.
According to the survey, most rural students still want to do it themselves, but the main reason is that they are afraid of breaking the instrument, do not know how to operate it, and are introverted. Only by finding the crux of the problem can we prescribe the right medicine. I think we should start from the following aspects to stimulate students' practical ability: (1) chemistry experiment is life-oriented. For example, an experiment in the first semester of the ninth grade chemistry textbook explored the burning of candles. The teacher arranged for students to prepare their own experimental equipment in advance, so that they could finish the experiment in the classroom and get busy preparing candles, glasses, matches, hydrated lime, knives and sticks after class. Results After the experiment, the students' faces were filled with joy. It turns out that chemical experiments are so simple. Then another experiment was "exploring the difference between the air inhaled by human body and the air exhaled". I also arranged for students to prepare their own drinks, such as straws, sticks, hydrated lime, etc., and replaced the sink with a washbasin. I only provided the students with two gas cylinders. In this way, we can not only find the preciseness and scientificity of special chemical instruments, but also find that many original chemical experimental instruments can be replaced by daily necessities, thus unlocking the mystery of chemical experiments. (2) Open chemistry experiment. Most chemistry teachers pay attention to strictly following the operation steps, what to do in this step, what to do next and so on when guiding students to complete the experiment. In this way, students don't have to think at all, just follow the prescription step by step intuitively, and can't cultivate their experimental ability. The author thinks that the experiment should be slightly "open", and the teacher only guides the general ideas, steps and schemes, which can be left to the students to complete themselves. At first, students may feel at a loss, but if they persist, under the guidance of teachers, students can develop a good habit of paying equal attention to both hands and brains. It can also satisfy the curiosity of some students who study well. (3) treat students with praise and appreciation. In fact, rural students are as curious and eager to explore as urban students. As an experimental teacher in rural areas, we should praise students who dare to start work from time to time, completely dispel their timidity, and gradually reverse their introverted personality until we select a few students to stand bravely on the podium and calmly complete a demonstration experiment. The teachers are calling on the students to give warm applause. Excellent experimental students are trained in this way. (4) Rational use of experimental substitutes, experimental teachers in rural areas should be good at developing rural curriculum resources and invigorating experiments. When students use substitutes to complete the experiment, they will not worry about being criticized and damaging the instrument, but will boldly carry out the experiment.
My idea also has many shortcomings. First, my level is limited, and the countermeasures are only at the empirical level, and the theory is not yet mature; There are many issues involved in this paper, and I only think of a few of them. The others are not mature yet, and I will consider them further in the future teaching.