在夏天,我们常遇到雷雨天气,可是为什么闪电的时间只是一瞬,而打雷声轰隆半天不断?还有,为什么夜间声音传得又远又清楚?以至于唐朝张继著名诗句“姑苏城外寒山寺,夜半钟声到客船”千古流传。 有人会说,夜间安静,声音传得远。这当然是一个原因,但是它并不是最主要的原因。关键是夜间声音传播拐了弯。首先,声音是声源的振动扰动了空气,扰动以波的形式向外传。设想声源是地面上空的一个点,如果空气中部分声音传播的速度是相同的,由此传出的声波的波前 In the summer, we often experience thunderstorms, but why is the lightning flashing only for a moment and thunder banging for a long time? And why is the sound at night so far and clear? As far as the famous verse of the Tang Dynasty Zhang Ji’s “Sugu City” Outside the Hanshan Temple, the sound of passengers is heard at midnight. Some people may say that the night is quiet and the voice is far away. This is certainly a reason, but it is not the main reason. The key is to turn the sound at night. First, the sound is the vibration of the sound source that perturbs the air, and the disturbance spreads outward in the form of waves. Imagine that the sound source is a point above the ground. If some of the sound in the air travels at the same speed, the wavefront of the sound wave that is transmitted