“差异法”是自然科学研究中常用的一种逻辑方法和实验方法,也是自然教学中培养学生逻辑思维能力和实验能力的一个重要内容。所谓“差异法”就是通过观察、分析一个现象在某一场合下能出现,而在另一场合下不能出现,这两个场合只有一个条件不同,其余的条件完全相同,证明那个不同的条件就是导致该现象发生的条件。本文试以“露”为例,谈谈“差异法”教学的一般程序。 Difference Law is a kind of logical method and experiment method commonly used in natural science research. It is also an important content of cultivating students' logical thinking ability and experimental ability in natural teaching. The so-called “difference law” is through observation, analysis of a phenomenon can occur under a certain occasion, but can not appear in another occasion, the two occasions, only one condition is different, the rest of the conditions are exactly the same, proving that the different conditions are Conditions that cause this phenomenon. This article attempts to “dew”, for example, to talk about the “difference method” teaching general procedure.