目前,学校一般使用的楞次定律演示教具还是20世纪80年代就已使用的教具。比如,用线圈加电流表,再外加一块磁铁,并利用磁铁插入和拔出线圈的方法观察感应电流的方向以判断感应电流的磁场方向,从而分析得出楞次定律。这种通过感应电流的方向判断感应磁场的方向,再与原磁场方向比较以推导楞次定律的方法,具有复杂、不直观的缺陷。笔者查阅了大量资料,并考虑了成本和效果因素,特设计了两个有针对性的楞次定律演示教具。下面,笔者谈谈以一块铁硼强磁铁和漆包线为主要材料设 At present, Lenz’s law teaching aids used in schools are still used as teaching aids in the 1980s. For example, with a coil plus ammeter, plus a magnet, and the use of magnets inserted and pulled out of the coil method of observing the direction of the induced current to determine the direction of the induced current magnetic field, thus Lenz’s law was analyzed. The method of judging the direction of the induced magnetic field by the direction of the induced current and then comparing with the direction of the original magnetic field to derive the Lenz’s law has the defects of being complex and not intuitive. The author consulted a large amount of information, and considered the cost and effect factors, specially designed two targeted Lenz’s law teaching aids. Here, I talk about a piece of iron and boron magnets and enameled wire as the main material