人教版《生物学》七年级上册有一个演示实验“种子在萌发的过程中放出什么气体”(如图1)。其中在图1实验过程中,往瓶内注入清水时,种子萌发产生的气体并不一定沿着导管进入到盛有澄清石灰水的试管中,而是从漏斗处逸出。分析其原因可能一是试管中的澄清石灰水较多,液面较高,产生 In the seventh edition of the Bibliotheque “Biology”, there is a demonstration experiment “What kind of gas the seeds emit during germination” (Figure 1). In the course of the experiment in Fig. 1, when the bottle is filled with fresh water, the gas generated by the seed germination does not necessarily enter the tube containing the clarified lime water along the conduit, but escapes from the funnel. One of the reasons for the analysis may be that the clarified lime water in the test tube is more and the liquid level is higher.