Exceptional singers are sometimes able to shatter a glass by singing at its natural frequency. It resonates, then explodes. People should make thin glasses that are sold tuned to a known frequency. Breaking glasses, I'll call them. There would be glasses for altos, tenors, sopranos and so on. With enough practice, anyone should be able to break a glass. It could be a neat exercise for singers, and maybe competitions could be held.-- Madcat, Jan 11 2004 One way to tune the choir, I guess.-- DrCurry, Jan 11 2004 Thank god I have polycarbonate lenses in my glasses.-- Letsbuildafort, Jan 11 2004 random, halfbakery