The Hague, 5 December 2024. The idea that a human voice can shatter glass has fascinated people for years, appearing in pop culture, science shows, and even advertisements. But how much truth is there to this myth? Could a singer really break a glass using only the power of their voice?
The science behind this phenomenon lies in resonance. When a sound wave hits an object, it causes the object to vibrate at a certain frequency. If the sound wave matches the natural frequency of the object, the vibrations can build up, causing the object to vibrate more intensely. This is known as an object’s resonance frequency.
For glass, this means that when a singer hits just the right note, one that matches the glass’s resonant frequency, the sound waves cause the glass to vibrate. If those vibrations become strong enough, they can lead to the glass breaking.
However, not just any old wine glass is susceptible to this. To achieve the dramatic shattering effect, the glass must have the right properties. Thin, high-quality wine glasses are typically used in these demonstrations because they have a clear, single resonant frequency that a singer can target. Cheaper, thicker glasses are much more difficult to break since their structure can absorb the sound energy more efficiently.
The note itself is typically a high-pitched one, usually around the frequency of 550 to 1000 Hz, depending on the size and shape of the glass. While it is theoretically possible for a singer to break glass with their voice, the reality is much more difficult. Most humans simply can’t sustain the necessary pitch and volume long enough to break the glass without amplification. In fact, it wasn’t until 2005 that anyone was able to accomplish this feat without using a microphone, when vocal coach Jaime Vendera shattered a glass on the TV show MythBusters by singing at over 100 decibels (which can be seen in the video below).
How can we apply this fun fact to the science of defect detection?
As sound waves travel through the air, they cause objects to vibrate at their natural frequency. If those vibrations grow too strong, they can break the object apart. This principle of resonance is more than just a party trick, it is the same fundamental idea that underlies much of acoustic testing in the modern world.
When it comes to testing materials, resonance helps reveal weaknesses. By sending sound waves through an object, we can detect how the material vibrates. If there are internal defects or weaknesses, those areas will behave differently when subjected to resonance, making it easier to identify problems without causing damage.
At RESONIKS, we use this principle in our acoustic resonance testing, combining sound waves and AI to detect subtle flaws in manufactured components. Just as a singer’s voice can cause glass to break, our technology identifies weak points in materials by studying how they respond to sound, ensuring that manufacturers can catch defects before they lead to failure.
