Science is mainly chemistry and physics, right? Chemistry: 1. Understand double base and master chemical terms. The so-called "double basis" refers to the basic concepts and theories of chemistry, which is an important part of the basic knowledge of chemistry and the basis for learning chemistry well. They are generally expressed in concise and clear words, which are scientific, rigorous and logical. When learning, don't just memorize, be good at grasping key words and phrases and understanding them accurately. For example, the key words of the catalyst concept are "variable", "before and after the reaction", "quality and chemical properties" and "unchanged"; The law of conservation of mass focuses on understanding "participation in reaction", "total mass" and "equality" and grasping "three conservation" (elements, atoms and mass). We should not only correctly understand double bases, but also use them. The so-called "chemical terms" refer to some chemical terms commonly used in the process of communication, description and expression of material changes in chemical science, such as element symbols, chemical formulas, chemical equations and so on. , to master, flexible use. 2. According to the structure, understand the essence of matter. The object of chemical research is matter. The composition and structure of matter determine the nature of matter, which restricts the way of existence, preparation and use of matter. Therefore, when studying the properties of elemental compounds, we should master their structures to understand the properties of substances. For example, when learning oxygen, we must think that oxygen is composed of many oxygen molecules, and one oxygen molecule is composed of two oxygen atoms. There are six electrons in the outermost layer of oxygen atom, which is easy to obtain, so the chemical properties of oxygen are more active. Many substances can change chemically with oxygen at room temperature, and when ignited or heated, a lot of heat will be released. After learning a lot of materials, we should be good at building related materials into a knowledge network, so that knowledge can be organized and grasped firmly. Attach importance to experiments and cultivate hands-on ability. Chemistry is a natural subject based on experiments. When studying the chemical properties of elemental compounds and conducting qualitative and quantitative analysis such as separation and purification, identification and identification, experiments are generally used to verify or explore and draw conclusions. Therefore, we must attach importance to experiments in order to learn chemistry well. From the simple use of commonly used instruments, the training of basic operation to the design of complex experiments, we should operate carefully and experiment boldly. The design of the experiment should be scientific and reasonable, that is, the device is simple, the operation is convenient, the program is reasonable and the phenomenon is obvious. Teachers should carefully observe and actively think about demonstration experiments in class, and master the principles, steps, phenomena and essentials of experiments. Students' experiments and family experiments arranged in textbooks are the best opportunities to cultivate their practical ability, so they should actively participate and do it seriously. 4. Pay attention to learning methods and improve learning effect. Chemistry in Grade Three is enlightenment chemistry, with many and miscellaneous basic knowledge points. With the accumulation of knowledge, some students' learning methods are improper, which leads to the decline of chemistry scores and even the weariness of learning. Therefore, to learn chemistry well, we must pay attention to the learning methods and improve the learning effect. Common effective learning methods are: (1) binary knowledge comparison. Such as combination and decomposition, oxidation and reduction. (2) the network of material properties. For example, related substances containing carbon elements can construct the systematic memory of carbon chain knowledge network. (3) Classification of similar knowledge. Such as the properties of H2 and carbon monoxide, the equipment for preparing H2 and carbon dioxide, etc. (4) Dispersed notes of chemical terms. Such as elements, atoms, molecules, valences, chemical formulas and chemical equations. , are scattered to each chapter according to the knowledge ladder for memory. (5) Cross-knowledge entry point. For example, the entry points of materialized knowledge include density, pressure, buoyancy, gravity, lever principle, electricity and so on. The entry point of biochemical knowledge is photosynthesis, respiration, greenhouse effect, ozone hole and red tide. 5. Timely feedback, strengthening exercises After learning each chapter, we should consolidate what we have learned in time, check the weak links in our study, and choose some classic exercises appropriately, but we must overcome the problem of blindly doing problems and falling into the sea of problems. Don't just stare at the topic when doing the problem, try to expand your thinking. For example, when doing calculation questions, pay attention to selecting some good questions related to daily life and combined with inquiry learning. Try to solve as many problems as possible, change or seek the law of solving multiple problems, and cultivate the ability of analyzing, solving and creative learning. 6. Expand knowledge and read extracurricular reading materials. In order to expand knowledge horizons, summarize knowledge content, improve problem-solving skills and master problem-solving methods, it is very necessary to order a high-quality, accurate and practical synchronous counseling material. For example, The Journal of Middle School Students' Physics and Chemistry is a good teacher and friend of teaching and learning, and it is worth reading. Physics: (1) three basics. Basic concepts should be clear, basic laws should be familiar, and basic methods should be skilled. Give an example about the basic concept. For example, speed represents the distance traveled by an object in a unit time: v = s/t, and for the basic law, for example, the formula for calculating the average speed is also v = s/t, which is applicable to any situation. For example, the speed of a 100-meter athlete is 65438+100-meter/s when passing half the distance, and it is 8m/s when reaching the finish line. The time for running the whole course 100m is 12.5s, and what is the average speed? According to the law of average speed, the average speed is equal to V = 100/ 12.5 = 8m/s, and then let's talk about the basic method. When learning junior high school physics problems, sometimes we should pay attention to choosing "objects". For example, when solving problems with ohm's law, it is necessary to make clear whether ohm's law applies to the whole circuit, that is, the whole circuit, or to a certain resistor, that is, a single resistor. (2) Do the problem independently. Do some problems independently with good quality and quantity (meaning not relying on others). There must be a certain number of topics, not too few, but also a certain quality, that is to say, there must be some difficulty. Anyone who studies mathematics and physics can't learn this level well. Solving problems independently may sometimes be slow, sometimes you have to take detours, and sometimes you can't even solve them, but these are normal and the only way for any beginner to succeed. (3) Physical process. To clarify the physical process, there must be hidden dangers in solving problems if the physical process is not clear. No matter how difficult the topic is, try to draw as much as possible, some can draw sketches, and some need to draw accurate pictures, using compasses, triangles, protractors and so on. To represent geometric relationships. Drawing can turn abstract thinking into image thinking and master physical process more accurately. With this diagram, we can make state analysis and dynamic analysis. State analysis is fixed, dead and discontinuous, while dynamic analysis is alive and continuous, especially when solving circuit problems. Without drawing a circuit diagram, it is difficult to know whether the resistors are connected in series or in parallel. (4) attending classes. Listen carefully in class and don't think or think as little as possible. Don't be self-righteous, learn from the teacher modestly. Don't give up listening just because the teacher speaks simply. If this happens, it can be regarded as review and consolidation. Try to be consistent and synchronized with the teacher, and you can't do it yourself, otherwise it will be self-study. After getting started, with a certain foundation, you are allowed to have your own activity space, that is, you are allowed to have something of your own. The more you learn, the more things you have. (5) notebook. Class is mainly based on listening, and there are notebooks, and some things should be written down. Knowledge structure, good problem-solving methods, good examples, places you don't understand, etc. Should be recorded. After class, you should organize your notes. On the one hand, you should "digest" and on the other hand, you should supplement your notes. Notebook is not only to remember what the teacher said in class, but also to make some reading notes. Good problems found in homework and good solutions should also be recorded in a notebook, which is what students often call a "good problem book". Hard-won notebooks should be numbered, studied later and kept for life. (6) learning materials. Learning materials should be well preserved, classified and marked. The classification of learning materials includes exercises, papers, experimental reports and so on. Marking refers to, for example, marking exercises. General questions are not marked. Good questions, valuable questions and error-prone questions are marked differently for future reading. Marking can save a lot of time. (7) time. Time is precious. Without time, there is no time to do anything, so we should pay attention to making full use of time, which is a very superb art. For example, we can save time by "recalling" learning methods. Before going to bed, waiting for the bus, walking on the road, etc. We can recall the lessons of the day section by section, so that we can learn them again and again and achieve the goal of strengthening. Some physics problems are more difficult, and some problems may be solved on foot. People who study physics often have several problems in their minds that they can't do and won't forget. I don't know when they will make a breakthrough and find the answer to the question. (8) learn from others. We should learn from others, from our classmates, from people around us and see how others learn. We should often have "academic" exchanges with them, teach each other, learn from each other and improve together. We must never be self-righteous. Cann't be conservative Tell others if you have a good method, so that others will tell you that you have a good method. You should have some good friends in your study. (9) Knowledge structure. We should attach importance to the knowledge structure, master it systematically, and systematize scattered knowledge. From the whole knowledge structure of physics to the knowledge structure of mechanics, even to chapters. (10) Mathematics. The calculation of physics depends on mathematics, which is too important for learning physics. Physics is difficult to do without mathematics as a calculation tool. In the physics department of the university, mathematics and physics are equally important. To learn mathematics well, we must make good use of this powerful tool. (1 1) Sports activities. Healthy body is the guarantee of good study, and vigorous energy is the guarantee of high efficiency in study. You should always take part in sports activities, know one or two kinds of exercise methods, take part in sports activities all your life, and do sports activities continuously. Just because you are interested in fishing for three days and drying the net for two days, it will not do much good to your health. Consciously exercise. To ensure adequate sleep, it is not advisable to increase study time by reducing sleep time. You can't get some good grades at the expense of overdraft health, you can't talk about the so-called "sprint" and "struggle" at every turn, and you should pay attention to the regularity in your study, that is to say, you should always work hard and don't engage in surprise attacks. .

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