我們的耳朶以聲音形式感覺到的聲波是傳播在空氣中、水中和固體中的彈性波。振動的聲源壓縮和它緊挨着的媒質微粒,它們又把這個壓縮傳給相鄰的媒質層,於是與稀疏波互相更替的壓縮波傳到該媒質所佔的整個空間。說明每一聲波特點的物理量是每秒鐘交替的稀密波的數目,即該聲音的振動頻率。不同頻率的 The sound waves that our ears feel in the form of sound are elastic waves that spread in the air, in water, and in solids. The vibrating sound source compresses the medium particles next to it and passes the compression on to the adjacent medium layers, so that compressional waves that alternate with the sparse waves propagate to the entire space occupied by the medium. The physical quantity that characterizes each acoustic feature is the number of alternating dilute waves per second, ie, the vibrational frequency of the sound. Different frequency