我们在实验室所用的试管架,在具体操作使用过程中存在许多不足,如图1所示。①备用试管放在前面,挡住了后面试管中的现象,影响观察。②正在反应的试管,放在试管架,没有背景,要想让学生观察清楚,只好用白纸或黑纸作背景,操作复杂。③教师取用不便,不易移动。为了解决以上不足,参 The test tube racks used in our laboratory have many deficiencies in the specific operation and use, as shown in Figure 1. 1 The spare test tube is placed on the front, blocking the phenomenon in the back test tube and affecting the observation. 2 The test tubes that are being reacted are placed on the test tube racks. There are no backgrounds. To make students observe clearly, they have to use white or black paper as the background and the operation is complicated. 3 Inconvenient for teachers to use, it is not easy to move. In order to solve the above problems,