According to the characteristics of middle school physics, this paper puts forward the learning method of "observation, thinking, experiment and transfer", and illustrates the specific requirements with examples.

[Keywords:] physical learning methods to observe the transfer of experimental thinking

Physical learning methods are closely related to the discovery of physical laws. Throughout the history of physics development, every discovery made by physicists is inseparable from observation, experiment, thinking and migration. In physics learning, observation is the beginning of learning, thinking is the relationship of learning, experiment is the means of learning, and transfer is the purpose of learning.

1 observation

Observation is a process of making full use of various sensory organs and perceiving physical phenomena (including experimental phenomena) in nature. Galileo realized the synchronization of the pendulum by observing the swing of the chandelier. When Renford was engaged in the manufacture of firearms, he observed that the temperature of metal fragments under the borehole was extremely high. He thought that so much heat was not provided by metal, and made a series of experiments on metal drilling. According to the experimental results, Lunford asserts that the heat card theory is not credible and that heat should be regarded as a form of motion. Later, David of England made a more rigorous experiment, which laid the experimental foundation for heat as the motion form of matter particles. People's correct understanding of the objective world is formed on the basis of repeated observation and experiment. Since observation is so important, what specific observation methods and requirements should be mastered in learning physics knowledge?

1. 1 methods and steps of observation

① Be fully prepared before observation. That is, it is necessary to prepare observation tools and records.

(2) Concentrate, don't give up accidental goals, and don't let go of those phenomena that you even think are irrelevant. Long-term training makes it a meticulous scientific habit.

(3) Repeated observation, find out the reasons of some phenomena in the experiment, and see the essence through the phenomena.

(4) Summarize after observation, carefully analyze the observed phenomena and recorded data, form physical concepts and establish physical laws. For example, to observe the convex lens imaging experiment, we must first make it clear that the position changes of candles and screens and the changes of images on the screen are mainly observed in the experiment. In this experiment, we should pay attention to the position of candle, screen and image. In order to observe these phenomena more accurately, we can carry out many experiments, and finally sum up the relationship among object distance, image distance, focal length, image reality and magnification.

1.2 observation requirements

① Quickly. In physics experiments, many experiments need to accurately read two or more data in a short time, which requires fast observation speed.

2 accurate. Is to reduce the error caused by observation.

3 profound. It is to grasp the phenomena that are often hidden, but often the essential physical process. For example, in the floating and sinking experiment, the rubber film on the bottle mouth is pressed by hand, and the floating and sinking will sink. The essence of sinking caused by downward pressure is that downward pressure reduces the volume of the air column above the float and the buoyancy it receives.

4 be careful. The changes of some physical phenomena are not obvious, so we need to observe them carefully to distinguish the subtle differences.

2 thinking

Thinking is an indirect and general reflection of the human brain on the objective world, and it is a process of processing perceptual materials obtained through observation and experiment into rational knowledge. Learning process is a kind of thinking activity, and thinking activity also has certain procedures and methods.

2. 1 physical thinking program

Physical thinking is to upgrade perceptual knowledge gained from physical phenomena and experiments to rational knowledge, and gain new rational knowledge from existing rational knowledge. The main procedure of physical thinking is questioning and resolving doubts.

(1) Questioning: Questioning is not a general question that you don't understand, but mainly refers to a difficult problem that the observer can't explain after making full use of his knowledge. Therefore, correct questioning is directional and enlightening for further study and research. There are many ways to ask questions, but the depth of questions is closely related to the observer's observation ability. For example, in the experiment of observing sinking objects, some people only found a simple relationship between depression and sinking. Some people can find the essential reason why depression leads to sinking.

2 dispel doubts. Questioning is the premise of solving doubts, and existing knowledge is the priority of solving doubts. When the existing knowledge has obvious difficulties in explaining doubts, creative activities should be carried out for the difficult parts. To solve the puzzle, we should start with the basic concepts and laws of physics, first analyze physical phenomena, find out the essential factors that produce these phenomena, and then choose appropriate physical knowledge to answer physical questions.

Problem: All three thermometers show the position of 20℃, but the scale of one thermometer is not accurate, so the temperature measured by one thermometer is definitely inconsistent with the actual temperature. What caused the deviation of actual temperature in (a), (b) and (c)?

Note: In the laboratory, the alcohol in the cup in Figure 2 (c) is communicated with air, and its temperature is lower than room temperature due to the heat absorption of evaporation. Although the bottle in Figure 2 (b) is also filled with alcohol, it will not evaporate, so its temperature should be the same as room temperature, so it can be judged that the thermometer scale in Figure 2 (c) is not accurate.

2.2 the basic method of physical thinking

The methods of physical thinking include analysis, synthesis, comparison, abstraction, generalization, induction and deduction. In the process of physics learning, abstraction and generalization are the main ways to form physical concepts, deduction, induction and generalization are the main ways to establish physical laws, and the methods of analysis, synthesis and comparison run through the whole physical thinking. Especially in solving physical problems, analytical methods and comprehensive methods are more widely used, such as the following methods and divergent thinking methods.

(1) The final method, that is, the forward reasoning method, is a method of inferring results from known conditions.

(2) Divergent thinking method, that is, starting from a certain physical law, find out various manifestations of the law. This is an important way to form skilled skills. For example, based on ohm's law and the characteristics of series-parallel electric energy, the following conclusions are drawn: the total resistance of series circuit is greater than any partial resistance, and the total resistance of parallel circuit is less than any partial resistance; In the series circuit, the voltage across the resistor with large resistance is large, and the voltage across the resistor with small resistance is small; In parallel circuit, the resistance with large resistance value passes through small current, and the resistance with small resistance value passes through large current.

3 experiment

Experiment is the foundation of physical science and the source of physical knowledge. Strengthening experiments is the characteristic of the times and the premise of improving the quality of physics teaching. Similarly, experiment is also an important method to form physical concepts and establish physical laws. Physics learning is to obtain the necessary perceptual knowledge through physical phenomena and processes, which can come from the physical facts provided by students' lives and experiments. The perceptual materials obtained from life usually come from complex sports forms, and essential and non-essential factors usually blend together. It is quite difficult to form concepts and establish laws only in this way. Experiments can provide simplified and purified inductive materials. It can make students have a clear and concrete understanding of physical facts. For example, in junior high school physics textbooks, the factors affecting evaporation speed are directly analyzed and summarized from daily life experience; The occurrence of sound is the conclusion drawn from the analysis of experimental phenomena; The lever balance condition is a conclusion drawn from a large number of experimental data after induction and necessary mathematical treatment. The pressure of liquid is to draw qualitative conclusions from experimental phenomena first, and then seek a strict quantitative relationship.

In the process of physics teaching, the importance attached by physics teachers to experimental teaching is an important factor affecting the teaching quality, and the importance attached by students to experiments is an important factor affecting the learning quality. When learning physics, we should do the following: ① Observe the classroom demonstration experiment carefully. 2 independently complete the students' group experiments and extracurricular small experiments, and try to dare to do it. ③ Design and make some simple models or toys by yourself. ④ Gradually form the habit of solving physical problems by experiments.

move

Migration is the application of basic principles under other conditions. As the saying goes, applying what you have learned is to apply what you have learned and methods to social practice. Its essence is migration. In physics, there are many contents that embody the principle of migration. Specific performance in the following aspects.

4. 1 Transfer of mathematical knowledge

Physics often uses mathematics to express physical concepts and describe physical laws. For example, the density of matter (ρ = m/v) is described by applying the proportional relation in mathematics. The speed of motion of an object (v = s/t), Newton's second law (a = f/m), etc. Using the coordinate image method in mathematics, the temperature-time image (representing the melting and solidification process of a substance), displacement-time image, velocity-time image, energy-displacement image and so on are described. The propagation, refraction and reflection of light are represented by geometric methods in mathematics.

4.2 the transfer of physical knowledge

The transfer of physical knowledge is manifested in three aspects. First, apply physical knowledge to solve problems. In physics textbooks, there are exercises after units and chapters. Secondly, the application of physical knowledge to explain natural phenomena, such as solar eclipse and lunar eclipse, can be explained by the principle of straight-line propagation of light. The reason of state change can be explained by molecular motion theory. Mirage wonders can be explained by the refraction principle of light. Third, apply physical knowledge to design and make various products. For example, thermos bottles are made according to the principle of heat transfer, generators and electronic measuring instruments are made according to the principle of electromagnetic induction, thermometers are made according to the principle of thermal expansion and contraction, and cameras, slide projectors and film projectors are made according to the principle of light refraction and reflection.

4.3 the transfer of physical concepts

In the process of its formation and development, physics has gradually formed a view of matter, that is, matter exists in interaction, in motion and in the transformation and conservation of energy. Therefore, mechanics is formed by studying the laws of force, motion and mechanical energy of macroscopic objects. Study the laws of force, motion and internal energy of molecules to form heat. Studied the laws of force, motion and energy between electricity and magnetism, and formed electromagnetism and so on. When we study physics, when we form this view of matter, we will purposefully know and understand the laws of interaction, movement and transformation, and energy conservation, and our study will be by going up one flight of stairs. The correct learning method is the golden key to get twice the result with half the effort. However, successful learning depends on hard work-observation, thinking, experiment and migration.

PS: It involves a lot. You can choose a few of them.