The wave has always been a most important and sacred form to me. One of my favorite places to be is cradled in the middle of an ocean wave as it carries me to shore. Quantum physics reveals that all of reality is waving even as we stand solidly within it. Now that is one tiny sacred wave, let me tell you! So infinitesimal that we cannot feel it, but, truth be told, we are solidly in motion. We move through our lived experience on great waves of vibrating energy.
Thanks to Trudie’s insatiable curiosity about life, I have been continuing my education through free on-line courses. A few months ago, we studied basic physics. I love the basics. Basics are the source, the juice, the impetus. If one does not go back to the basics on a regular basis, then one loses touch with the core. And, when it comes to physics, all that I understand is the basics. Those basics are so mind boggling that when the instructor moved into the mathematical minutia, I lost interest and was awash in wonder.
So one of the physics lessons was on sound and waves. Even though I have taken a number of sound related courses and had sound waves explained over and over again, the lens of physics allowed for a bigger picture. A wave is generally defined as “a disturbance moving through a medium.” I really like the idea of a moving disturbance – something happens, something is initiated and that action dances a form. So the template emerges over time. You can capture a moment of the form in a snapshot, but that is not the full form. You can illustrate the movement of the form in a diagram or drawing using mathematical formulas to see the wave at specific points in time, but this is not the full form either. The form in its entirety must be experienced as a process – from initiating action/disturbance to the last moment of decay before the medium returns to its pre-disturbance state. This last “way of knowing” is the phenomenological experience of the form. We can grasp parts of the form with diagrams and measurement, but to know the form in its wholeness, we must engage it with our attention and our senses. We must experience it as it unfolds before us.
As the waveform unfolds, it is important to remember that the wave and the medium are separate phenomenon. This means that they can move in different relationships to each other. A transverse wave moves up and down at right angles to the motion of the medium. An ocean wave is a perfect example of a transverse wave. A longitudinal wave moves the same direction as the medium in a kind of pulsing motion. Sound waves are longitudinal waves. When the air (the medium) is initially disturbed, there is a bumping up of the air molecules which causes them to bunch together. The wave travels through the medium by alternately bunching and dispersing, bunching and dispersing. The bunched up molecules are called the compression aspect of the wave and the dispersed molecules are called the rarefaction aspect of the wave. So sound waves travel in a pulsing longitudinal path:
I was confused when I first learned this concept because in my audio work I am used to seeing this familiar waveform pattern that actually looks more like a transverse wave to me:
Thanks to the physics explanation, I realized that this waveform is not illustrating a wave to medium relationship. It illustrates an amplitude to frequency relationship – amplitude and frequency being the characteristics of a sound wave. This is the picture of a single sound wave which can be experienced through head phones as a sine wave.
When we have two sound waves and they meet. they interact to create a superposition wave. This wave comes into being through the constructive and destructive interference patterns between the two original waves. In other words, the places where the frequency and amplitude patterns of the two waves come together is constructive and where they move apart is destructive. When the waves are two different frequencies, the superposition wave creates what we perceive as a beat. As the waves interact over time, the pulse of the shifting interference patterns creates the beat. If you are a singer and would like to experience this phenomenon, sing the same pitch with a partner, then one of you move off that pitch ever so slightly. You will experience a full body “hearing” of the beat that the superposition wave creates. It is quite powerful and amazing.
Here is an audio example of two waves at two different frequencies and the vibrating “beat” of the superposition wave they create. First you will hear a single tone and then I will add a tone that is a half step higher. You will hear two sets of tones- the first higher set will have a faster beat. The second set is lower and you will hear a slower beat that wavers and throbs.
Lets go back to that quantum wave I was talking about in the opening paragraph. Those molecules that are disturbed and initiate the pulsing longitudinal waves that become sound are made up of another type of wave: electromagnetic waves. Some scientists are realizing that these tiny waves are existence itself. I wonder how those quantum waves are effected when they are disturbed as a group in our observable reality? How do quantum waves and observable waves interact with each other?
The mystery just keeps unfolding.