Summary of knowledge points in the second volume of physics in the second day of junior high school, as detailed as possible.

The contents of the second volume of junior high school physics textbook for Grade 8 * * include four chapters, which are ohm's law, electric power, electricity and magnetism, and information transmission. They are all outstanding contents of electricity and magnetism.

Chapter VI Ohm's Law

Requirements of curriculum standards:

1. Understand some characteristics of semiconductors and the impact of the development of semiconductor materials on society.

2. Understand some characteristics of superconductors and the possible impact of superconductors on human life and social development.

3. Be able to connect simple series circuits and parallel circuits. Can tell examples of using series circuit and parallel circuit in daily life and production.

4. Explore the relationship between current, voltage and resistance through experiments, understand Ohm's law, and make simple calculations.

5. Know how to use ammeter and voltmeter.

6. Know about home circuits and safe electricity use, and be aware of safe electricity use:

Overview of the whole chapter.

1. Voltage. Measurement of voltage.

2. Explore the law of voltage in series circuit.

3. The concept and unit of resistance, the structure and function of rheostat.

4. Ohm's law, the relationship between current and voltage resistance and the harm of short circuit.

5. Measure the resistance of small light bulb.

6. Ohm's law and safe electricity use.

Textbook. Our teachers should guide students to observe and arouse their thinking. Can ask: is there a relationship between electricity and lightning in life? To stimulate students' interest in exploring the mysteries of nature.

Section 1 Voltage

What is the unit of voltage for students to understand through this section? How to measure voltage? This is the most basic requirement for students.

voltage is an important concept in electricity, which is the basis of studying ohm's law. This section focuses on practicing using voltmeter.

figure 6.1-1 shows the lightning phenomenon simulated in the laboratory, that is, the high-voltage discharge phenomenon of the starter. Compared with the first picture in the chapter, it can make students think that natural phenomena are also related to scientific experiments. Teachers can try to simulate experiments and demonstrate the discharge phenomenon.

the formation of the concept of voltage: the textbook learns from the word "voltage" that students are familiar with in daily life. The textbook only talks about what voltage is.

Teaching suggestion: Enlightening question: Where have you heard of the concept of "voltage" in your daily life? Let the students discuss, read, think and answer, and let them know the voltage from practice.

think and do: ask students to carefully observe the voltage changes and brightness changes at both ends of the light bulb. Let the students perceive the relationship between the brightness of the light bulb and the voltage, thus leading to the effect of the voltage. That is, to generate a current in a circuit, there must be a voltage at both ends. Then explain the function of power supply, voltage symbol and unit.

how to connect the voltmeter: it is the focus of this textbook, which removes the narrative introduction of the use of the voltmeter in the current textbook, but allows students to learn by themselves according to the instruction manual and use the voltmeter to ask students to read the instruction manual of the voltmeter with questions to obtain the required information. So as to cultivate students' reading ability.

suggestion: teachers can let students read the instruction manual of voltmeter first, and then exchange the obtained information to talk about the connection method of voltmeter. At the same time, let the students design a circuit to measure the two ends of a small bulb with a voltmeter according to the usage of the voltmeter, and do the experiment. In this way, students have developed the habit of cooperation and communication with others.

teacher's attention: the difference between the connection of voltmeter and the old textbook: in the past, the voltmeter was connected in parallel with some circuits. The current flows from "+"to "-",which is too abstract. Nowadays, it is more intuitive, accurate and operable.

How to read on the voltmeter: The textbook does not tell the method of reading, but uses analogy and association to let students think about the method of reading on the voltmeter. Teachers should not tell directly in teaching. Show the ammeter first, let the students talk about the reading method of ammeter, and then think about how to talk about what you are inspired by the reading of ammeter. Try the reading of the voltmeter boldly.

think about it: battery series connection is a common problem in life. Through students' hands-on experiments and analysis of measurement, it is not difficult to get the characteristics of series battery voltage, that is, let them perceive that the series battery voltage is more than that of a single battery and equal to the sum of the voltages of three series batteries.