一、案例背景在《串联电路的应用(一)》学习伏安法测电阻的课堂中,学生已具备有欧姆定律、串联电路特点等知识为基础。学生已经知道用电流表、电压表测电阻的原理,也知道需要多次实验可以减小实验误差。但,学习串联电路特点后,由于学生的认知水平和能力基础,他们对实现多次测量的认识过程,要从“利用电池节数来改变电压”变化到“利用滑动变阻器改变电压”是有一定困难的。尤其是滑动变阻器的接入,使电路变化较多,对学生思维品质的要求较高,可同时,对思维品质的提高也较多。授课教师利用对比模式,通过学生回顾测电阻的原理以及多次测量的方法,经历同伴间的讨论、分析和比较,得出“利用滑动变阻器改变电压”的方法,在此基础上修改原有的实验方案,并进行学生实验,由此体会串联 First, the case background In the “series circuit applications (a)” learning volt-ampere method of measuring resistance in the classroom, students already have Ohm’s law, the characteristics of the series circuit knowledge based. Students already know the ammeter, voltmeter resistance principle, but also know that the need for multiple experiments can reduce the experimental error. However, learning the characteristics of the series circuit, due to the cognitive level and ability of students based on their understanding of the process to achieve multiple measurements, from the “use of the battery section to change the voltage ” change to “using a sliding rheostat to change the voltage ”There is a certain difficulty. In particular, sliding rheostat access, the circuit changes more demanding on the quality of the students thinking, at the same time, improve the quality of thinking are more. Learners use the contrast mode, through the students to review the principle of measuring resistance and multiple measurement methods, experiencing peer discussion, analysis and comparison, come to “use of sliding rheostat to change the voltage ” method, on the basis of modifying the original Some experimental programs, and students experiment, which experience tandem