对比式液体电阻演示器

Demonstrating liquid resistance through comparison

现行教材中关于电阻大小与导体的材料、长度、横截面积、温度有关的实验只是用固态(金属)材料做实验得出结论,对于液体是否也符合该规律,教材未做详尽说明.为此,利用注射器等材料制作了对比式液体电阻演示器,该演示装置可探究柱状液体的电阻与液体成分、长度、横截面积、温度的关系.

The resistance of a conductor is related to the material resistivity, length, cross section and temperature. To demonstrate the relation, solid metals are used in the experiment introduced in the teaching material. However, whether the resistances of liquids follow the same relation is not expatiated. So the author designed a device to compare the resistances of liquids using injector and other materials. The device can easily demonstrate the relations between the liquid resistance and the liquid material, length, cross section and temperature. The phenomenon is obvious.