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教学中发现学生对俯视或仰视仪器导致测定结果偏大或偏小这类问题弄不清楚,现以三种玻璃仪器的使用和读数为例分述并小结。要彻底解除学生这方面的疑惑,教学中应首先让学生注意以下几点:1援对于量筒和滴定管来说:首先要将读数和量取区别开来。读数是液体一定,视线不同读出的结果是不同的。量取则是刻度一定,视线不同量出的结果也不同。但无论是读数还是量取,视线都应与量筒或滴定管内凹液面的最低处保持水平,否则就会出现误差。
Students find it difficult to determine whether the results of overlooking or looking up the instrument are too large or too small. The use and reading of the three glass instruments are used as examples and summarized. To completely dispel students’ doubts in this area, students should first pay attention to the following points in teaching: 1 Aid For measuring cylinders and burets: First of all, it is necessary to distinguish between readings and measurements. The reading is a certain amount of liquid, and the result of reading is different depending on the line of sight. Measure is a certain scale, the results of different amounts of sight are also different. However, whether it is reading or measuring, the line of sight should be kept level with the lowest point of the concave surface in the measuring cylinder or burette, otherwise errors will occur.