Singing Bowl Resonance and Harmony
Published on 21 Sep 2023
Sound therapy has become very popular in recent years. It is said that the sound produced by singing bowls can put the listener in a meditative state and relax, thereby reducing stress.
To play a singing bowl, the bowl must be struck or the edge of the bowl must be rubbed with a mallet, producing vibrations that in turn become the sounds that we hear. The size, thickness, and material of the singing bowl, as well as the mallet used to strike it, also affect the tone produced. Adding water to the bowl will lower the frequency of the singing bowl's vibrations, resulting in a deeper, more sustained sound.
Sometimes you can see that when the player continues to wipe the edge of the singing bowl, the sound of the singing bowl will become louder and louder, and the water will splash! In fact, this is related to the phenomenon of resonance.
All objects have their natural frequency. When the frequency of friction is close to the natural frequency of the singing bowl, resonance will occur, which greatly increases the amplitude of the singing bowl and produces a louder sound. In addition, if there is water inside the bowl, as the singing bowl vibrates and produces sound, its edge begins to change shape, switching back and forth between slightly oval shapes, and in this way energy is transmitted to the water, generating waves. When the frequency of friction is close to the natural frequency of the singing bowl with water added, it causes a standing wave pattern due to resonance, a phenomenon called Faraday waves. The pattern of water waves becomes more complex as the vibration frequency increases. When the amplitude continues to increase and exceeds a threshold, water splashes.
This water wave phenomenon is so fascinating that there are even studies dedicated to recording and figuring out how to create specific patterns. Can you think of other resonance phenomena or Faraday waves that you come across in daily life?
Image courtesy of John W. M. Bush, Dept. of Mathematics, MIT.