Chemistry teaching itself is not only to teach students some preliminary chemical concepts and laws, but also to improve students' intelligence in an all-round way through a series of effective educational and teaching means, so that they can master and apply some chemical principles and experimental means, learn the basic methods of scientific research, and learn to understand the world dialectically and objectively, so that they can further study and engage in socialist modernization independently and creatively in the future. Using chemical experiments and a series of effective methods and means can better develop students' intelligence.
First, around the "three principles" to guide students to carry out experimental thinking activities
The main content of chemical experiment theory can be summarized as (1) experimental principle; (2) device principle; (3) Working principle. Teachers should guide students to explore, understand and discriminate the above-mentioned "three principles" in the specific chemical experiment teaching process, and carry out thinking training activities throughout.
The first is the thinking training of experimental principles. "Experimental principle", that is, reaction principle, refers to the theory that every specific chemical experiment reflects or explains or infers which substance has changed. It can arouse students' thinking around the following angles: 1. The nature of change-what chemical substances (sometimes further analysis is needed to find out why these substances are chosen)? 2. Quantitative relationship-what kind of substance quantity (or mass, or volume, or number of particles) is used between reactants? Why do you want to take this quantitative or excessive relationship? 3. Reaction conditions-what kind of material state, changing temperature, pressure or catalyst conditions should be selected during the experiment? Why do you choose such conditions? (1). Selection of instruments-According to the experimental principle, which instruments should be selected for measuring, mixing, reacting, heating, removing impurities, drying, testing, collecting, absorbing, separating and buffering (safely) a specific reactant or product? Why are these instruments more suitable? (2) Matching-according to the needs of the experiment, how should the dimensions and specifications of the selected instruments be coordinated? What's the harm if you don't make this combination? Can we make some kind of exchange or substitution? (3) Connection sequence-how to connect the selected instruments and the sequence of installation and disassembly in order to achieve good results? Why should we arrange this order? What are the bad consequences of not obeying this order?
Second, form the habit of careful observation and lay a solid foundation for creative thinking.
Einstein said that he had no special talent, only a strong curiosity. In the history of human cognition, it is the individual's curiosity and surprise about things or a phenomenon that leads to major inventions.
Chemistry is closely related to our life, and various phenomena related to chemistry can be seen everywhere. When building a wall with bricks and sticking tiles, first wet the tiles with water; Newly bought aluminum pot has black spots after burning tap water; Where there are frequent thunderstorms, seedlings flourish. These wonderful phenomena arouse students' curiosity and can prompt them to learn the properties of cement, aluminum and nitrogen.
We will also encounter some strange experimental phenomena. For example, an aluminum can filled with CO2 gas, and then an appropriate amount of NaOH solution is injected into the can, and the can mouth is immediately sealed with adhesive tape. What might happen after a period of reaction? First, the cans are "dented", and then "dented cans are bulging again". It is generally easy to explain the previous phenomenon. This is because it is easy for students to start from the inherent mindset, that is, when analyzing the changes of substances, only consider the added substances and only analyze the reaction between NaOH solution and CO2, and then they can get the phenomenon of "concave" of cans. Why does the latter phenomenon occur? After deep thinking, it is not difficult to draw a conclusion that this is because the "aluminum" in the container itself will also react with sodium hydroxide solution. Curiosity about these phenomena can make students feel excited and excited, thus generating sparks of innovation in white-hot thinking.
Generally speaking, students are interested in chemical experiments, but they are often driven by curiosity. Because the purpose of observation experiment is not clear, they are not good at focusing on the main phenomena of key equipment, and the instruments are small, the classroom is wide and there are many students in the demonstration experiment, so their observation experiment is not accurate. Therefore, teachers should try their best to change demonstration experiments into parallel experiments, or play experimental videos with the help of CAI software or VCD discs and videos, and combine parallel experiments or video playback as far as possible, interspersed with a series of thinking questions around the "Three Principles", to guide students to think pertinently and carry out thinking training activities.
Thirdly, the method of instilling creative thinking by typical experiments.
In order to improve the efficiency of thinking training in chemical experiment teaching, teachers should use typical chemical experiments to induce and stimulate students' thinking activities, which mainly start from three aspects:
First, teachers should grasp the whole syllabus and teaching materials macroscopically, plan which typical experiments students will carry out and what aspects of thinking training, and implement them in stages and at different levels. For example, substances have different characteristics when burning. Flames are generated when gases burn, and sparks or sparks are generated when solids burn. Sulfur is a solid under normal circumstances, but why does burning in the air produce a flame instead of Mars? As long as students are guided to observe the characteristics of sulfur combustion carefully, they can master the mystery. It turns out that when burning, solid sulfur is liquefied first and then gasified, so it is not surprising that sulfur vapor produces a light blue flame when burning in the air.
The second is to stimulate learners' subjective initiative, and change some demonstration experiments or students' experiments specified in the textbook into experimental design or experimental exercises, so that students can put forward their own implementation plans according to the experimental requirements, thus improving students' creative thinking ability. For example, when explaining the nature of iron to junior three students and doing a demonstration experiment of rusty nails, students can first find their own materials and prepare three clean medical injection vials 10 days before the experiment. Put a nail in three different environments: full water, little water and dry. Let the students observe once a day and make records. When talking about this sub-content, let the students bring "results", and combine the teacher's explanation with the students' discussion; The effect will be better until the correct conclusion is reached.
The third is to select some typical comprehensive experimental questions from the senior high school entrance examination papers to guide students to solve problems, and even combine hands-on experiments for training. There are many excellent typical chemical experiments in middle school textbooks and previous senior high school entrance examination questions, such as the preparation of hydrogen, oxygen, carbon dioxide and carbon monoxide and a series of experiments, which are quite effective in cultivating students' thinking ability.
To sum up, the conclusion is obvious: thinking training in chemical experiment teaching can not be ignored, and thinking training in chemical experiment activities has broad prospects and great potential. The observation of chemical experiments is generally carried out in the following order: (1) Observe the device diagram, select the instrument used, and understand its purpose and usage; (2) Observe the color and state of reactants; (3) Pay attention to the conditions of reaction and observe the phenomenon; (4) Observe the color and state of the product after the reaction. Should be done in turn, there can be no omissions. Practice has proved that paying attention to the observation process is an effective method to cultivate students' creative thinking.
Fourth, flexible use of demonstration experiments and group experiments to create a platform for students to show their thinking.
Demonstration experiment is a common teaching form in chemistry teaching. It is vivid, simple and effective, and it is one of the best teaching methods to cultivate students' ability of observation, thinking and operation. In the process of implementing demonstration experiment teaching, we divide the demonstration experiment in the textbook into three forms: (1) For important experiments, teachers demonstrate and students observe and analyze to draw conclusions; (2) For some experiments with low requirements, the laboratory can be opened to students, and students are required to design or improve their own experiments and then demonstrate on stage; (3) For some difficult, demanding and unobvious experiments, teachers should demonstrate first, so that students can ask questions in observation, discuss and analyze the defects of the experiments, and keep students in a state of inquiry thinking, thus improving the experimental effect. Change the group experiment into a single experiment, so that each student can do it by himself and operate independently. It is helpful to cultivate good study habits and make students understand that everything should be done with a purpose, a plan and the determination to stick to it. The most important thing is to cultivate the ability to work independently, which is also an ability that education itself urgently needs to cultivate.
Verb (abbreviation of verb) carries out scientific and technological activities and demonstrates innovative ability.
The foundation of innovation activities is scientific and technological activities, and the development of scientific and technological activities has a profound impact on innovation activities. Therefore, we must do everything possible to carry out scientific and technological activities in our work. Do not create any conditions. Starting from extracurricular interest groups, establish the foundation of initial innovation activities. Through the guidance of teachers, give full play to students' innovative ability and try to carry out extracurricular scientific and technological activities by using existing conditions. For example, students can finish the small family experiment in the textbook first; Combine textbooks, supplement some extra-curricular knowledge, broaden knowledge and conduct some interesting and meaningful experiments; And guide students to write small scientific papers. Fully demonstrate students' innovative ability.
In cultivating students' innovative activities, we should also pay attention to connecting with social reality. Students can be allowed to conduct social surveys and visit, visit and investigate in factories, villages, shops and other places. Write a special investigation report and put forward suggestions and measures for improvement in combination with social reality. If conditions permit, we can carry out research plans and help implement them.
It's finally finished. Are you satisfied?