“叫蝉”是一种用竹木制作的民间玩具,由鸣蝉(发音体)、细线和木棒构成(如图1所示).转动木棒,使细线带动鸣蝉做圆周运动,此时将会听到音调起伏变化的鸣叫声(类似蝉鸣).运用“叫蝉”作为演示实验让学生亲自体验音调变化的规律,从而引出多普勒效应,这不仅可以激发学生探索的兴趣, “Clam” is a folk toy made of bamboo and wood. It consists of a gong (sounding body), a thin line, and a wooden stick (as shown in Figure 1). The wooden stick is rotated so that the thin line will drive the gong to make a circular motion. At this time, you will hear the fluctuating sound of the fluctuating tone (similar to buzzing). Using “screaming” as a demonstration experiment allows students to personally experience the law of pitch change, thereby eliciting the Doppler effect, which can not only stimulate students to explore interest,