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初中物理课本第二册第129页有“用伏打电池给小灯泡供电”的演示实验。但在做这个实验时,随着反应的进行,由于铜片上会附着一层氢气泡,增加了原电池的内阻,阻碍了电子从负极锌片流向正极铜片,即铜片上发生“极化”现象,从而使小灯泡很快变暗直至熄灭。为此,我们对该实验作了一些改进,效果较好。现介绍如下。一、制作 1.电池液的配制: 在250ml的烧杯中倒入10％左右的稀硫酸约200ml。然后,加入适量的重铬酸钾,并搅拌,使之大部分溶解。
There is a demonstration experiment of “powering a small light bulb with a voltaic battery” on page 129 of the second volume of the junior high school physics textbook. However, during this experiment, as the reaction proceeded, a layer of hydrogen bubbles adhered to the copper sheet, which increased the internal resistance of the primary battery and prevented the flow of electrons from the negative electrode zinc sheet to the positive electrode copper sheet, ie, the “polarization” occurred on the copper sheet. "The phenomenon so that the light bulb dims quickly and goes out. For this reason, we made some improvements to the experiment and the results were good. The introduction is as follows. First, the production of 1. Preparation of battery liquid: In a 250ml beaker, pour about 10% of about 200ml of sulfuric acid. Then, an appropriate amount of potassium dichromate was added and stirred to dissolve most of it.