初中物理第二册实验一、导体和绝缘体实验为了培养学生的辩证唯物主义观点,防止他们认识上的绝对化,在演示了各种材料有不同的导电性之后,还要进一步演示导体和绝缘体之间没有绝对的界限,在一定条件下可以转化的现象。 1.用一根粗4毫米左右的玻璃棒,两端各缠上粗1毫米长20厘米的金属线,再串联一只40瓦灯泡,如图1所示。接入220伏特电压的电路中,灯泡不亮,用酒精喷灯对玻璃棒加热,则见灯泡 Physics experiment in junior high school second experiment, conductor and insulator experiments In order to develop students' dialectical materialist point of view, to prevent their understanding of the absolute, after demonstrating a variety of materials have different conductivity, but also to further demonstrate the conductor and insulator There is no absolute boundary, under certain conditions, the phenomenon can be transformed. 1. Using a glass rod roughly 4 mm thick, wrap the 1 mm 20 cm long metal wire at each end and a 40 W bulb in series as shown in Figure 1. Access 220 volts circuit, the light bulb is not bright, with alcohol torch heating the glass rod, then see the light bulb