“多普勒效应”是高二《物理》必修加选修课的内容 ,许多参考资料介绍多普勒现象时都用“火车鸣笛事例”加以阐述 :“当我们站在火车站的站台上 ,火车拉响汽笛急驶而过时会有两种截然不同的感受 .当火车朝我们开来时 ,汽笛声调变高———频率增大 ;当火车离我们远去时 ,汽笛声 The “Doppler Effect” is a compulsory addition to the “Physics” in the second year. Many references to the Doppler phenomenon are described in the “Training Trumpet Case”: “When we stand on the train station platform, the train There are two distinctly different feelings when the whistling sirens and the obsolete. When the train heads towards us, the tone of the whistle becomes higher—the frequency increases; when the train is away from us, the whistle