演示实验一般是配合教学进行的,基本要求之一是确保成功。但在许多情况下,演示实验不是费时太多,就是效果不明显,或实验误差太大,以致难以成功,造成整节课的失败。决定一个演示实验成功有效与否的因素是多方面的,但从实验装置结构方面去分析,造成演示效果不好的原因有:一是为实验提供能源或动力作用的部分可能欠佳或运用不当,如热 Demonstration experiment is generally carried out with teaching, one of the basic requirements is to ensure success. However, in many cases, the demonstration experiment is not too time-consuming, the effect is not obvious, or the experimental error is too large, so difficult to succeed, resulting in the failure of the entire class. There are many factors that determine whether a demonstration experiment is successful or not. However, the analysis of the structure of the experiment device is not good for some reasons. First, the part that provides energy or motivation for experiment may be poor or improperly used , Such as hot