09 Feb The True Nature of Reality: Sound Barriers – 17
In our last journaling exercise, Believing Is Seeing, we contemplated our inability to see the world in its entirety. In today’s journaling exercise, we will examine our ability to hear the world around us.
Just like sight, there are several frequencies of waves that can be perceived by vibration sensing organs like the ear. Not all of these frequencies, however, are perceptible to the human ear, and the range of audio wavelengths we are capable of hearing is limited. We share the world with several other species of animals that have different capabilities when it comes to hearing. A dog, for example, can hear pitches much higher than a human being. You may have seen or used something called a dog whistle, that when blown makes no apparent noise to us, but makes one that dogs can hear quite clearly.
While doing research on elephant communication, scientists believed they could feel vibrations in their bodies at times when the elephants were making no audible noises. It was later discovered, that in addition to the loud sounds we all associate with the elephant’s trumpet, they are also able to create low frequency waves known as infrasound. Like the high pitch of a dog whistle, these low pitched noises are also inaudible to the human ear. Perhaps even more fascinating, elephants are believed to have the ability to sense vibrations from the ground during communication, using the sensitive pads on their feet to receive vibrations and transfer them to their ears via bone conduction. Many animals are believed to have the ability to perceive infrasound, and in cases of natural disasters such as a tsunami, animals have been seen fleeing forests hours before the large wave makes landfall.
During highly stressful situations, such as hunting a wild animal or being involved in a shooting, many people report not hearing their own gunshots or perceive them as a very muffled noise. In several documented shooting incidents, police officers said they believed there was something wrong with their weapon or ammunition because their guns would not “go bang”. Remarkably, this phenomenon is not just the brain shutting down the noise, but consists of a physical reaction of the three bones in our ears used for hearing. Somehow, they are able to sense the front end of the shock wave of a loud sound and disengage the hearing mechanism before the audible blast reaches them, something that has to occur faster than the speed of sound.
Human hearing changes with age and as we grow older, the frequency range we hear starts to shrink with time. In many cities, businesses facing problems with loitering teenagers have started playing high frequency pitches that sound annoying to the teenager’s ears, but that are imperceptible to the adult ear.
Once again, the world we perceive, no matter how large it may seem, is just a very small sliver of what is out there.
If your hearing range was somehow augmented, what do you imagine a high pitched dog whistle would sound like?
What would the low pitched infrasound used by elephants sound like?
Name three sounds you find annoying. Why do they annoy you?
Name three sounds you find very pleasant. Why do you find them pleasant?
If you could hear the entire spectrum of sound, how would your life be different?
What is silence? Is silence relative?
If we perceive silence, but there are several noises going on around us that we cannot hear, then does silence actually exist?
What kind of conditions would be required to accomplish true silence?
Combine your inability to hear certain tones that are going on around you right now with your inability to see anything besides a small fraction of the light spectrum. Write down any thoughts you have.