初中化学课本氨分子的扩散实验按教材的实验步骤现象很明显，滤纸上的红色小斑点很快由外到里出现。但笔者把变红的滤纸条拿出试管，由于氨分子迅速扩散，可以看到红色斑点逐渐变淡，不到１min全部褪色，再把褪色后的滤纸条放进试管，又出现变红的现象。学生观察由滤纸条变红→ The experiment of diffusion of ammonia molecules in the chemistry textbook for junior middle school is very obvious according to the experimental steps of the teaching materials. The small red spots on the filter paper quickly appear from the outside to the inside. However, the author put the red filter paper out of the test tube, due to rapid diffusion of ammonia molecules, you can see the red spots gradually fade, less than 1min all faded, then put the faded filter paper into the test tube, and then turn red The phenomenon. Student observation turned red by filter paper →