论文部分内容阅读
在中学教材中,演示实验很多,借助投影手段,将某些实验现象清晰地呈现在每个学生面前是一种很好的方法,下面介绍几个实验的做法。 1 电解饱和食盐水制取氯气和烧碱 将培养皿置于投影器的载物台上,将饱和食盐水倒入培养皿中并滴入几滴酚酞。碳棒接低压电源的正极上,铁棒接在负极上;然后把碳棒和铁棒平行放入培养皿中,用透明胶片写上
In the middle school textbooks, there are many demonstration experiments. With projection methods, it is a good method to present certain experimental phenomena in front of each student. Here are some experiments. 1 Electrolysis of saturated brine for chlorine and caustic soda Place the Petri dish on the stage of the projector, pour the saturated salt solution into the Petri dish and add a few drops of phenolphthalein. The carbon rod is connected to the positive electrode of the low voltage power supply, and the iron rod is connected to the negative electrode; then the carbon rod and the iron rod are placed in the petri dish in parallel and written on the transparent film.