中学化学里所遇到的平衡问题较多。初中要学习溶解平衡,高中还要学习化学平衡、电离平衡、水解平衡等。这些都属于动态平衡。由于看不见摸不着,学生对动平衡的概念很难建立起来。笔者采用了一个小实验,可以帮助学生建立动平衡的概念。用品:底破孔的废试管一支(18×180或大些都可以,太小的不便于操作),在一定高度(比如离管底3～4cm处)套上一个橡皮圈做为标志。大烧杯两只(200～400ml均可),一只盛水,事先用红墨 The balance problems encountered in middle school chemistry are more. Junior high school should learn to dissolve and balance, and high school should learn chemical balance, ionization balance, hydrolysis balance and so on. These are all dynamic balances. Because students cannot see it, students’ concept of balancing is difficult to establish. The author used a small experiment to help students establish the concept of balancing. Supplies: A broken test tube at the bottom of the hole (18 x 180 or larger can be too small for easy operation), at a certain height (such as 3 to 4 cm from the bottom of the tube) put on a rubber band as a mark. Two beakers (200-400ml each), one full of water, with red ink in advance