实验一　将一些铁屑装入试管内 ,并用橡皮帽盖住试管口 ,然后用条形磁铁的一极在试管下沿同一方向移动几次 ,如图1所示 .观察　“试管”能吸起大头针等物 ,说明“试管”有磁性 .思考　“试管”为什么会有磁性呢 ?图 2这实际上是一个磁化现象 .原来 ,在磁性材料的内部有大量的磁 In the first experiment, some iron chips were put into the test tube, and the test tube mouth was covered with a rubber cap. Then one pole of the bar magnet was moved several times in the same direction under the test tube, as shown in Fig. 1. The observation “tube” could suck up. Pins and other objects indicate that the “test tube” is magnetic. Consider why the “tube” has magnetic properties. Figure 2 This is actually a magnetization phenomenon. It turns out that there is a lot of magnetism inside the magnetic material.