现行教材人教版初中化学的分组实验《分子运动》中 ,有这样一个实验 :氨分子的扩散。该实验在设计上存在的缺点主要有 :一是实验时间过长 ;二是操作不易 ,用滴管吸取浓氨水后 ,滴在试管口的脱脂棉上 ,易造成过多氨水流入试管中 ,与滴有酚酞试液的滤纸条接触 ,有碍得到正确的结 In the molecular experimentation of the current textbook, the junior high school chemistry grouping experiment, there is such an experiment: the diffusion of ammonia molecules. The experimental design has the following shortcomings: First, the test time is too long; Second, the operation is not easy, with a dropper to draw concentrated ammonia, drops in the test tube mouth of the absorbent cotton, easy to cause excessive ammonia flow into the test tube, and drops Contact with filter paper with phenolphthalein test solution hinders the correct knot