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新课标人教版生物学教材第四单元第三章第二节“发生在肺内的气体交换”的实验装置如图1所示。其操作方法是抑住鼻呼吸,用口对准丫形管呼气、吸气。呼气时,右手捏紧甲胶管,左手松开;吸气时,左手捏紧乙胶管,右手松开。用甲乙两个锥形瓶进行对比实验,实验现象明显,学生通过实验能认识到呼出的气体中含有较多的二氧化碳。但要注意的是,实验者的双手动作不能有差错。否则,要么在呼气时,将甲瓶中的石灰水吹
New Curriculum PEP teaching the fourth unit of the fourth chapter of the third chapter second “occurred in the lungs of the gas exchange,” the experimental device shown in Figure 1. The method of operation is to restrain the nasal breathing, mouth with the mouth alignment Ya breath, inhale. Exhale, the right hand pinch the hose, left hand release; inhale, pinch the left hand H tube, right hand release. With two conical bottles A and B comparative experiments, the experimental phenomenon is obvious, students can experiment to recognize the exhaled gas contains more carbon dioxide. But note that the experimenter’s hands can not make mistakes. Otherwise, either in the breath, the bottle of lime blown water