笔者对实验作如下改进:取内径与食指粗细相近、长约18厘米的两端开口的玻璃管一根,演示时将食指插入玻璃管使其一端密封,然后盛适量凉水,照图2那样给水加热,上面的水沸腾了,手指并不觉得烫。从而直接说明了水不善于传热。该实验取材容易,操作简单方便,收到了较好的教学效果。 The author made the following improvements to the experiment: Take a glass tube with an inner diameter similar to the size of the index finger, which is approximately 18 cm long, and open the glass tube at both ends. Insert the index finger into the glass tube to seal it at one end, and then fill with cold water. Supply water as shown in Figure 2. Heated, the above water boiled, and the fingers did not feel hot. This directly shows that water is not good at heat transfer. The experiment was easy to draw, simple and convenient to operate and received good teaching results.