Can an opera singer really break a wine glass by singing?

Jean Barrette, a physics professor at Canada's McGill University, says that you first need a high-quality wine glass. By that, he means a glass that will resonate strongly at a well-defined frequency and will maintain that resonance for some time.

To break the glass the singer would have to produce a very loud sound and maintain for several seconds the vocal pitch at the exact resonance frequency of the glass. By transferring energy to the glass this way, the singer would increase the vibration amplitude and that would eventually break the glass. It is likely easier for sopranos, or singers with a high pitch, to meet this challenge since when they sing, they produce a tone that is purer.

So if you're having an opera singer over for drinks, don't bring out the expensive stemware.