Introduction to Water and Sound

Water, a universal solvent, has a profound impact on the way sound is perceived and transmitted. Unlike air, water is denser and less compressible, which affects the propagation, quality, and perception of sound. In this detailed exploration, we will dive into how a piano's sound changes when played underwater. We will elucidate the physics behind the muffled and distorted sound, clarify why pitch alterations and resonance reduction occur, and discuss the unique challenges and insights this phenomenon presents.

Understanding Waves and mediums

Sound is a wave that requires a medium to travel through. Air, the medium we are most familiar with, allows sound waves to bounce off surfaces, creating echoes and reverberations. Water, though still a liquid, differs significantly in its properties and density. This dense medium dampens the vibrations of objects, such as the strings of a piano, affecting the sound in unique ways.

The Physics of Sound in Water

Inside a piano, sound is primarily created by the vibrations of the strings, which are transduced into sound waves through the soundboard and then distributed through the air. However, when the piano is submerged under water, several physical changes occur:

The density of water increases the resistance to the string vibrations, dampening and distorting the sound.

Water transmits sound differently; it cannot transmit sound in the same manner as air. This results in a significant reduction in the sound's resonance and clarity.

The pressure and density of water can also cause changes in the pitch, as sound travels at a slower speed through water compared to air.

Experimental Evidence and Examples

Several experiments and videos on the internet showcase the effects of a submerged piano. Most notably, the video by Mitsuku Aoki provides a dramatic visualization of a piano playing in a swimming pool. In these videos, the sound produced is muffled, and the notes are distorted, often sounding more like noise than a clear musical melody.

Scientific Explanations and Insights

The muffled and distorted sound of a piano underwater can be explained by the following scientific principles:

Water Density: Water is 800 times denser than air. This high density makes it harder for the vibrating strings to push the water away, significantly reducing the amplitude of the sound waves. This dampening effect is felt most prominently in low-frequency sound waves.

Reduced Resonance: The soundboard of a piano traditionally relies on air to help amplify the sound. When submerged, the soundboard's ability to resonate is compromised, further reducing the clarity and redundancy of the sound.

Sound Speed: Sound travels at approximately 1482 meters per second (m/s) in water, compared to 343 m/s in air. The slower speed reduces the perception of clarity and pitch.

Pitch Alterations: The reduced speed of sound in water, combined with the depth and pressure effects, can cause slight pitch alterations as the sound waves interact differently with the environment.

Conclusion

The sound of a piano when played underwater is a fascinating demonstration of the effects of water on sound waves. While the basic sound is still recognizable, it is heavily altered due to the unique properties of water. Understanding these changes provides valuable insights into the mechanics of sound and the elasticity of musical perception. For a more in-depth exploration of these phenomena, check out my Quora Profile for more detailed discussions and insights.