My teenage son and I were chatting in a hotel room, in a country that had just opened its borders to the outside world. We were facing an open window, 50 feet from another tall building. Between my son and me was a nightstand with an empty drinking glass on a plate. It was bright daylight. Suddenly, the glass shattered with a sharp crackling sound, in front of our eyes, into more than 20 glass fragments, crumbling to lie in a clump on the plate. We looked, but saw, and heard, nothing unusual, especially nothing coming from the other building. It was a strange, somewhat scary moment, which to this day I cannot totally explain.
The cracking of the glass reminded us instantly of great opera singers hitting the highest note, and shattering wine glasses in the line of the sound waves. At least that’s what happens in movies. Supposedly, at a particular sound frequency, glass can definitely “resonate” and shatter. It’s spooky however when it happens right before your eyes, without a visible or audible high-pitched opera singer!
Recently several members of the US Embassy in Cuba were evacuated because of damage to their inner ears, allegedly from some kind of spying efforts from local government, using sound wave bombardment. I’m not sure that is related to our story, but who knows? And I’m glad my son and I escaped damage to our inner ears! At least that I know of…
Indeed, all kinds of sound waves come at us from all kinds of directions, some we hear, and some we do not. Obviously, we do not hear all sounds, and some people are more sensitive than others. We had a child at church who had an amazing ability to hear conversations in the next room, even very soft ones. Which could be unnerving for friends of the family! He became too sensitive to normal sounds, and was even a troubled child apparently because of that. Too many and too loud sounds can make for great discomfort.
Indeed, many people are super sensitive to specific sounds such as chalk screeching on the blackboard, or metal on china. It can “drive some people crazy,” or make their ears painful. You might be one of these people, so you understand. There is just such a huge variability in even the “normal” perception of so-called “normal” sounds.
We all know how dogs can listen to sounds beyond our own range of sounds, so that we can use a dog whistle, at a higher frequency beyond our normal reception, and therefore inaudible to us, to summon it. And if we watch deer carefully in the backyard, we can also see that their ears are definitely much more sensitive than ours, and will sharply flip upright, and face left or right, to catch sounds coming at them, which we may not hear.
And obviously we use sound waves beyond our own perception, for health purposes. Nowadays, it is so common to use ultrasound (echo) machines, to visualize organs within the body, or even babies in the womb. Even though I have seen lots of baby echoes as part of my profession, it’s always amazing to see an “echo” baby sucking his thumb in the womb!
Our hearing system is so intricate and complex that we can readily hear and understand a huge range of musical sounds and diverse complex languages. Numerous computer-like designs are necessary for this to happen just “naturally.” Just to allow sound to go from outer eardrum, to microscopic ear ossicle bones, to inner eardrum, to microscopic semi-circular canals, to thousands of microscopic sensory hairs arranged like beautiful musical keyboards, which can sense complex sounds that will transmit along fine nerves all the way to complex brain areas of reception. An entire sound-initiated journey that is superbly amazing, and basically unbelievable without a Master-Musician-Linguist-IT- Designer!
What indeed would happen if we did not have this wonderful sound system? We would not be able to hear beautiful songs, there would be no need for musicians, schools would be severely limited in how to educate children, there would be no use for sound alarms, there would be no whispers of love, we would not be able to hear the scolding from our Asian parents! The whole world would be entirely changed. What would it be like to live in a world of silence?
How does the system ever work? How is it possible that all these absolutely critical steps can be all tied together synchronously, and super-complexly, in order for us to appreciate the beauty of sound? We stand in awe of the intricacies of sound, even though at times it can break glass, or screeching noises can make us go crazy! Humility and awe are great habits for everyone, and especially those like us who study science and use sound waves a lot!