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初中物理第二册第八章“决定电阻大小的因素”一节和高中[甲种本]物理第二册第七章“电阻定律、电阻率”一节中研究“决定导体电阻大小的因素”,如果让学生观察一个直观性强的小实验,学生学后印象深刻。为配合好教学,笔者设计了一个“液体变阻演示实验”,效果令人满意。器材:玻璃缸一只、食盐水、面积相同的铜片(或铁片)两块、米尺一根、电池组(两节干电池)一个、电珠(1.5V或2.2V)一只、电键一个、导线四根(其中有两根是焊接在A、B片上的)。方法和步骤: 在玻璃缸内装一些食盐水,缸上放一米尺,缸内导电液体中两边各插入一块面积相
The chapter “Determining the size of the resistance” in the second volume of the junior high school physics booklet and “The factors determining the size of the conductor resistance” in the section entitled “Resistance law, resistivity” in Chapter 7 of the second edition of Physics in the second edition of Physics. If students are allowed to observe a small, intuitive experiment, students will be impressed after studying it. In order to coordinate with the teaching, the author designed a “liquid variable resistance demonstration experiment” with satisfactory results. Equipment: one glass jar, salt water, two copper sheets (or iron sheets) with the same area, one meter, one battery pack (two dry batteries), one power cord (1.5V or 2.2V), one key , four wires (two of them are welded on A, B film). Method and procedure: Place some salt water in the glass jar, put one meter rule on the cylinder, and insert an area phase on both sides of the conductive liquid in the cylinder.