阅读下面这首古诗，完成两小题。
                                                                                                              齐安郡中偶题
                                                                                                               （唐）杜牧
                                                                                           两竿落日溪桥上，半缕轻烟柳影中。
                                                                                           多少绿荷相倚恨，一时回首背西风。
                                                                                                             暮热游荷池上
                                                                                                            （宋）杨万里
                                                                                             细草摇头忽报侬，披襟拦得一西风。
                                                                                             荷花入暮犹愁热，低面深藏碧伞中。

（1）高压锅是利用增大气压，使水的沸点____ 的原理来更快煮熟食物的。
（2）船闸利用的是____ 原理；
（3）飞机能飞上天，是利用空气对它产生的____ （选填“浮力”或“升力”）。

下列物质属于纯净物的是(  )