“焦耳定律”是高中物理“稳恒电流”一章的重点,也是教学难点。本节课教学的主要目的有两点: 1.设计一组对比实验,使学生从观察实验中,进一步了解电流的热效应产生热量与I~2、R、t三个物理量成正比关系。(本节重点) 2.设计一个测定电动机转动与不转动两种情况下,电功与电热关系的学生分组实验,进一步从能量转化和守恒的观点阐明电功和电热的关系。 “Joule’s Law” is the focus of the chapter “Steady Current” in high school physics, and it is also a teaching difficulty. The main purpose of this lesson is two aspects: 1. Design a set of comparative experiments, so that students from the observation experiment, to further understand the thermal effect of the current heat production and I ~ 2, R, t three physical quantities are proportional to the relationship. (The focus of this section) 2. Design a student grouping experiment to determine the relationship between electric power and electric heat under the two conditions of motor rotation and non-rotation, and further clarify the relationship between electric power and electric heat from the perspective of energy conversion and conservation.