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不少物理教师反映,初二物理(沪科版)《6.2磁场》一节图6-16(P55页)所示的磁屏蔽实验看起来很简单,实际上不大好做.笔者经多次实验,发现做好这个实验有两个关键:(1)磁铁的磁性要强,以保证足够的吸力(笔者用旧扬声器或电动机上的磁铁替代 U 形磁铁,效果更好).(2)铁片要有一定的厚度(4mm 左右),太薄不行,磁感线易泄漏.但是照书去做,效果还是不理想.主要问题是当在磁铁与回形针之间
Many physics teachers report that the magnetic shielding experiment shown in Figure 6-16 (page P55) of the 6.2 Magnetic Fields in the 2nd grade Physics (Shanghai edition) looks very simple and is actually not very easy to do. The author has conducted many experiments. , found that there are two key to doing this experiment: (1) The magnetic properties of the magnet should be strong to ensure sufficient suction (I prefer the old speaker or magnet on the motor to replace the U-shaped magnet, the effect is better). (2) There is a certain thickness (about 4mm), too thin, magnetic inductance line is easy to leak, but according to the book, the effect is still not ideal. The main problem is when the magnet and the paper clip