Beats

Acoustical Beat Periodic change in sound intensity caused by interference between two nearly identical sound waves They occur when the frequency of the 2 waves is nearly identical You hear beats as a change in loudness, from soft to loud

You can use beats to assess small differences in frequency between 2 waves When you tune an instrument, by checking the frequency of the beats, you can tell how well the instrument is tuned.

Beat frequency Frequency of the beats produced by the interference of 2 waves with slightly different frequencies. It is equal to the difference in frequencies of the 2 interfering waves video

How does it work? Strike a tuning fork and a piano key at the same time Keep tuning string by adjusting the tension until you don’t hear any beats