Tip of the Iceberg

Anyway, to explain the title of this entry. I occasionally make comments to Greg about the art of barbershopping, particularly in reference to the underlying mathematics and physics behind the type of sound barbershoppers aim to produce. In response, he sometimes gives me some mental gristle to chew on. In that vein, he recently made me aware of an intriguing concept: sonic levitation. Over the last couple centuries, a greater understanding of the physics of sound has led various researchers to investigate the possible applications of harnessing the energy of sound waves. One of these applications is the seemingly ridiculous possibility of levitating an object by focusing interwoven sound waves upon it. Strangely enough, this is actually being accomplished. Granted, on very small objects (i.e. semiconductor wafers), but stranger still is that this has led some historians to theorize, and produce convincing arguments, that this technique was used even in ancient times to assist in some, or all, of the large-scale construction projects that now baffle us. Like, for example, the Pyramids. It seems incredulous, but there may actually be truth in this. Some of what follows gets a little complex, but if you're already intrigued, bear with me.

Every object has a "resonant frequency": a pure tone directed at the object - or within a container, such as a musical instrument or even a room - will be hugely amplified if the frequency is perfect for that object's material and structure. If the tone is resonant (in other words, contains underlying tones of other frequencies), such as that produced by any human voice, only the resonant frequency will be amplified; the rest will be discarded. Barbershoppers exploit this fact all the time by singing chords that are structured such that not only the primary tones sung by each singer are amplified by each other, but the underlying "harmonics" amplify the primary tones and each other. When done correctly, this results in an enormous expansion in amplitude (perceived by the ear as volume) with little energy expended on the part of each singer. This makes sense when you consider that sound is a wave - alternating peaks and valleys - and therefore multiple sounds that overlap will either cancel each other out (if the peaks of one line up with the valleys of another) or expand each other. We refer to a room as having good acoustics if this effect is enhanced by the way that the sound waves are reflected by the size, shape and physical makeup of the room.

Furthermore, sound waves are created by vibrations, and are therefore not only produced by energy but contain energy... in other words, sound is a form of radiation. So an increase in a sound's amplitude is an increase in its energy. As the barbershop style demonstrates, the easiest way to increase the amplitude of any sound is to produce another sound with a different frequency but identical resonance. Jim Richards, author of "The Physics of Barbershop Sound", has actually come up with an equation that summarizes this well: F / (W0 - W1) = A. Expressed in English, this reads as follows:

Frequency (F) divided by the difference of two resonances (W) equals amplitude (A).

The implication of this is that if the different resonances are identical, we're dividing by zero. I was told in grade school math that you can't do that, that the result will be invalid. According to Jim, that's not actually true: whenever you divide by zero, no matter the numerator, the result is always infinity. In other words, two sounds of different frequencies but identical resonances results in infinite amplitude. Infinite energy.

Which brings us back to sonic levitation. When the energy of sound is focused into an object using the correct frequency for that object, the molecules are actually "excited" to the point that it counteracts the force of gravity acting upon the object. If the ancient Egyptians were in tune (oops, pun) enough with nature - and what little we actually know of their culture would seem to support that assumption - to be able to ascertain the resonant frequency of large stone blocks, it's conceivable to imagine that they devised a method to focus enormous energy into them by an act as simple as chanting or humming, even to the point of making the blocks weightless enough to make a construction effort that would otherwise be seemingly impossible more attainable.

Finally, I submit that George Lucas may have been closer to the truth than he realized when he came up with the idea of what we now call the "Jedi mind trick": moving objects by thought alone. As ridiculous as the idea would have seemed to me only a week ago, I now find myself admitting that it could be possible. We often refer to brain activity as "brain waves"... if that's indeed accurate - if the firing of synapses is truly an electrical process, which would therefore generate some radiation, no matter how minute, and that radiation is emitted in the form of a wave - then it would theoretically be possible to overlap these waves in such a way as to produce infinite amplitude. This would require, however, multiple waves of identical resonance to be emitted simultaneously. In other words, an identical thought by multiple people, or multiple simultaneous thoughts by one individual. Come to think of it, this might even lend mathematical credence to the Judeo-Christian concept of the "power of prayer". It would certainly seem to explain the dynamics between different individuals or groups of people... although this is typically referred to as "chemistry", it may be that the true explanation lies in the realm of physics.