Can sound crack glass?

Yes, sounds can indeed crack glass. Singers with strong voices have been known to crack wine glasses by hitting the right pitch and sustaining a loud enough note. For example, there is a tale of the famous tenor Enrico Caruso being able to break glass: the opera singer steps onto the stage, and as he hits a high note, the sound shatters glass in the room.

In the 1970s, Ella Fitzgerald broke a glass with her voice. However, the sound was amplified to over 100 decibels through Memorex speakers.

While this is possible, it can only occur under very specific conditions. This phenomenon is related to the concept of resonance. Here’s how it works:

1. Resonant Frequency: Every object, including glass, has a natural resonant frequency, which is the frequency at which its particles vibrate most intensely. If a sound wave is produced at the same frequency as the resonant frequency of the glass, the glass will start to vibrate more forcefully, and with enough energy, it could eventually break.
2. Amplified Vibrations: As the sound continues at this frequency, the vibrations of the glass can become more and more intense. If the sound is loud enough (high amplitude), these vibrations can increase to a point where the glass can no longer handle the stress, causing it to crack or shatter.
3. Required Conditions: For sound to actually crack glass:

• The sound must be at the same frequency as the glass’s resonant frequency.
• The sound must be loud enough (often requiring a sound level of over 100 decibels or more).
• The glass must be fragile enough (thin wine glasses are often used in demonstrations).

references:
How to break glass with sound -bbc.com
Can an Opera Singer Break a Glass with their Voice? -soundplanning.co.uk