“焦耳定律实验”是初中物理的重要内容 ,但笔者认为按现行教材 ,教学中存在三个问题 .1 .用两次实验说明电流越大 ,产生的热量越多 ,但不同的电流所产生的液柱高度不能直接比较 ,演示效果差 .并且两瓶中电阻丝的阻值和两次实验时的电流值没有确定的倍数关系 ,不能直接从实验中 “Joule’s Law Experiment” is an important part of junior high school physics, but I believe that according to the current teaching materials, there are three problems in teaching. 1. Use two experiments to show that the greater the current, the more heat is generated, but the different currents are generated. Liquid column height can not be directly compared, the demonstration effect is poor, and the resistance value of the resistance wire in the two bottles and the current value of the two experiments have no definite multiple relationship and cannot be directly from the experiment.