Can a soprano shatter someones spectacles by singing a loud, high note?
The answer is no, but the question is not as bizarre as it sounds. Consider the phenomenon of resonance. Some systems, such as a child on a swing or a wine glass, can vibrate and store energy of vibration at a particular frequency, their resonant frequency. I give my nephew on the swing a gentle push, then another, then another… after 20 pushes he is flying three metres in the air, which is far higher than I can throw him. The energy of all the successive pushes has been stored in the vibration. Some wine glasses can ring spectacularly at a particular frequency: give them a flick and a nearly pure sine wave sounds. Suppose that the singer sings this frequency (it falls in the soprano range, and operatic sopranos are good at concentrating lots of energy in the fundamental frequency). A little sound energy gets stored in the glass with each vibration cycle and eventually a substantial amount of energy is stored in the glass, causing oscillations of large amplitude. If you use very high
