现行湘教版《化学(九年级)上册》专题2“利用大气资源”单元一“多组分的空气”里面“空气中氧气体积含量测定”的实验(23面图2-1),许多教师在做这个实验时往往会发现进入瓶内的水的体积大于瓶中空气体积的1/5(如图1所示),为什么会出现这种现象呢?笔者经过反复研究发现,产生这种情况的原因是由于烧杯的液面高于集气瓶中的液面,发生了“虹吸”现象。在实验中该如何避免这种现象的发生呢? The current version of the Hunan version of “Chemistry (Grade 9) Volume 2” using atmospheric resources “unit a” multi-component air “inside ” Determination of oxygen content in the air “experiment -1), many teachers in this experiment will often find the volume of water into the bottle is greater than the volume of air in the bottle 1/5 (as shown in Figure 1), why this phenomenon occurs? The author after repeated studies It was found that the reason for this was that a ”siphon" phenomenon occurred because the liquid level in the beaker was higher than the liquid level in the gas cylinder. In the experiment how to avoid this phenomenon?