实验室有一根外形与条形磁铁一样的金属棒，为判断其是否就是条形磁铁，请写出两种方法。

 阅读下面的诗歌，完成后面的题目。

                                                                                                                  约 客
                                                                                                                 赵师秀
                                                                                                          黄梅时节家家雨，

                                                                                                          青草池塘处处蛙。 

                                                                                                          有约不来过夜半， 

                                                                                                          闲敲棋子落灯花。