Optimizing Physics Teaching with Experiments

Physics is based on observation and experimentation, the construction of physical models, the application of mathematics and other tools, through scientific reasoning and argumentation, the formation of a systematic research methodology and theoretical system. The basis and carrier of physics teaching is experiment. Physics laboratory teaching is an important form and method of physics teaching. Generally divided into demonstration experiments, in-class experiments (experiments while lecturing), student group experiments and extracurricular experiments. Physics classroom teaching in a reasonable use of physics experiments for students to create a sensible, vivid, image of the physical scene, it is easy to guide students from the interest of physical phenomena to the learning of physical theory. And students through the observation of the experiment, from which the relevant perceptual material, not only for the understanding and mastery of the content of the textbook to prepare, but also for the students to correctly form the physical concepts, understanding and mastery of the laws of physics, cultivate the students' observation ability, hands-on ability, thinking ability and creativity has a very obvious role. In this paper, the capacitance of the capacitor as an example, the application of physical experimentation in classroom teaching to discuss.

First, the use of living experimental teaching aids, stimulate students' interest, the establishment of scientific concepts

Capacitors are a new electronic component that students have never touched. For students capacitor is an abstract concept, the lack of necessary perceptual knowledge, it is difficult to establish a correct and clear concept. How to let students quickly establish the concept of capacitors, understand its structure and role, is the focus of this section.

The teaching of the use of common objects in life - cans as a teaching aid to introduce the theme. Raise the question: cans as a water container for liquids, can be loaded with electricity? Stimulate the curiosity of students, put forward a variety of conjectures. Then the cans are charged, and then tested with a sensitive ammeter. When the ammeter pointer deflection, confirmed that the cans can indeed be loaded with electricity, and then lead to the concept of capacitors. Why cans can hold electricity? The cans of capacitors for the big reveal, so that students understand the basic structure of the capacitor, two close to each other and each other insulated conductors can form a capacitor.

The experimental device from life, easy to make, the experimental effect is obvious, greatly stimulate the students' interest in learning. Famous physics educator Prof. Zhu Zhengwu said "altar cans when the instrument, put together to do experiments", that is, in the physical laboratory teaching to vigorously advocate doing simple and easy alternative experiments. Through the concept of water containers and capacitors analogous design, so that students can more easily understand the concept of capacitors, clear capacitor role. Finally, the last to "physical + picture" form of display, rich perceptual understanding, to promote the formation of rational cognition.

Second, the application of diversified experimental means to cultivate students' experimental observation ability

The process of charging and discharging capacitors is the main form of capacitor work, but also a carrier for students to understand the capacitor. In the can demonstration experiment, has shown the charging and discharging process of the capacitor. But for students this feeling is indirect. Therefore, the teaching of the design of student experiments, so that students personally experience the charging and discharging process of capacitors, and in the process of experiments to discover the unknown phenomena and laws, to develop students' experimental observation skills.

The digital experiment can collect data in the experimental process at a high frequency and monitor the dynamic experimental process, which cannot be realized by the traditional experiment. The experiment collected real-time data of the voltage and current of the capacitor in the process of charging and discharging, and presented the change curve of the two over time through the image. The application of digital sensor experiments enables the dynamic change process of charging and discharging to be clearly, completely and intuitively presented, so that the students' understanding of capacitors is more specific and richer.

The combination of student group experiments and digital demonstration experiments in the classroom, both rich perceptual understanding, and accurate and efficient data collection and processing, realizes the learning process from qualitative perception to quantitative analysis and verification, and in-depth excavation in the consolidation of knowledge.

Third, the integration of thinking experiments to design experimental programs to promote scientific investigation

Another capacitor using 220V charging, wire shorting accompanied by a "pop" sound to see a bright spark discharge. Comparison of the discharge phenomenon with the can capacitor, indicating that the capacitor's ability to store electricity is different. So, how to compare the capacitor's ability to store electricity? Through the previous experiments and theoretical analysis, students have mastered the charge of the capacitor, the potential difference between the plates, these basic concepts. Integration of the above, the following conclusions can be drawn:

1. The more charge the capacitor plate, the more obvious discharge phenomenon;

2. capacitor charging is completed, the potential difference between the plates and the supply voltage is equal.

3. The charge of the capacitor is related to the potential difference between the plates, the greater the potential difference between the plates of the same capacitor (i.e., the greater the charging voltage), the greater the charge carried by the plates.

Based on the above conclusions, how to describe the capacitor's ability to store electricity put forward conjecture: with the charge? Or with the voltage? If the charge is used as a parameter to describe the capacitor's ability, in different charging voltage, the capacitor carries a different amount of charge. And the capacitor voltage can not be increased indefinitely, more than a certain limit value, the capacitor will be damaged, this limit value is called breakdown voltage. Can we compare the charge voltage of a capacitor by comparing the storage capacity of the capacitor. Question: at the same voltage, different capacitors store the same amount of charge? Inquiry 1 task activity through experimentation (student experimentation). Students have already had experience with the first experiment and will soon be able to take measurements of different capacitors and draw conclusions from their observations and comparisons. Different capacitors do not carry the same amount of charge at the same charging voltage. Therefore, the charge or potential difference cannot be used singularly to express the capacitor's ability to store electricity. However, there is a positive correlation between the charge and potential difference of a capacitor, can we find a breakthrough by quantitatively investigating the relationship between charge and potential difference? (Inquiry task two demonstration experiment) analogous to the Coulomb torsion scale experiment in the idea of equal distribution of charge, the transfer of the learned scientific method, applied to the new content of the study of the investigation, not only consolidate the original knowledge, but also to achieve a breakthrough and innovation. Using this method successfully solved the problem of difficult to measure the charge, more accurate to get the quantitative relationship between the charge and the potential difference. This leads to the concept of capacitor capacitance. The process of experimentation on the operation and indoor environmental requirements are high: the indoor air should be as dry as possible, the experiment needs to use the exact same capacitor, the experimental process needs to be rapid and coherent, to avoid the time is too long capacitor electrode leakage, discharge, resulting in a large error in the experimental data.

Fourth, return to life, contact with reality, cultivate a sense of innovation

Capacitors in a variety of electronic instruments are widely used, but the students are not familiar with capacitors, because they rarely open the electrical appliances to observe the components. After students recognize and learn the knowledge of capacitors, then show the application of capacitors in life. Examples include power adapters, cell phone touchscreens, computer motherboards, the inner workings of household appliances, and supercapacitors for electric cars. Have students look at the circuit boards of used appliances to find the capacitors inside. Through such activities, students will realize that there are capacitors inside almost all electronic devices and appliances. The learning of physical concepts and laws, if only stay at the level of analysis and memorization, students will feel boring to understand, and must go to life in order to learn and use the knowledge alive. Finally, the end of the classroom homework assignments, in addition to completing the corresponding knowledge of the textbook exercises, but also requires students to make their own capacitors using common household items around them. To achieve learning to use, physics from life, and return to life.

V. Summary

In the process of teaching physics, experiments can constantly stimulate students' interest in learning physics, deepen students' understanding of abstract concepts, so experimental teaching in the physics classroom has an irreplaceable role. For teachers, to do a good job in an experiment-based physics class, teachers need to pay a lot of effort to prepare before class, including the preparation of teaching aids, experimental design, experimental debugging, as well as experiments and classroom convergence and integration, which require teachers to repeatedly test before class, pondering and pondering. Physics laboratory teaching is not only a test of teachers' hands-on experimental ability and subject-specific knowledge, but also a test of teachers' adaptability, creativity and other comprehensive qualities, which are constantly improved in physics laboratory teaching. In the continuous process of experimental teaching, gradually realized the education of teaching and learning.