A Nice Clean Plate
   It's Saturday evening. Bruce is having a birthday party. There are a lot of children at the party. They play together for an hour. Then Bruce's mother gives them some food. But she forgets to give Sam any.
   Sam feels wronged(委屈) but then he remembers his mother's words, “Be polite.(礼貌). Don't ask for food.” So he waits for a few minutes, then he holds his plate up over his head and says loudly, “ Does anyone want a nice clean plate?”

小明利用玻璃瓶、细管和带颜色的水自制了一个气压计和一个温度计（如图甲和乙所示）．下列说法错误的是（　　）