Hearing happens in an instant - quick transformations to energy until the movement of molecules is meaningful to a listener. It’s not magic, but the small size and complexity of shapes, movements and structures involved in energy transformation makes the process seem magical. To be able to hear beautiful music or birdsong in spring or mother’s voice is an awesome act of nature.
To put it very simply, sound is a type of energy and to get it from outside the head to the place in the brain where it can be “heard,” sound energy has to be sent from the microphone to the amplifier, along wiring, and on to the translating device.
Outer Ear
The ear that seen on the side of the head acts like a satellite dish that catches waves of sound. This outer ear is shaped to funnel and swirl the sound of energy made when molecules move as they are displaced by air, water or solid objects. The displacement forms waves that flow into the ear hole. In the tunnel that leads to the ear’s complex structures, the molecules move closer together and become louder.
On to the Middle and Inner Ear
Just about an inch past the ear that is seen outside the body and inside the ear hole, sound energy beats on the ear drum. The rhythm is taken up and passed along by three very tiny bones. In the middle ear compartment, the mechanical action of the bones amplify the air waves.
Now in the form of mechanical energy, the wave moves on to another tiny membrane that leads to the shell-shaped and fluid-filled inner ear. In the shell, called the cochlea, sound energy swims through the fluid and strums across teeny, tiny hairs that bend and snap. Damage to these hairs or cilia is all too common due to loud noise and traumatic brain injury and often results in an annoying condition called tinnitus.
On to the Brain
Energy fires neurons bundled into the nerve of hearing, the auditory nerve. The nerve’s long wires or axons zings energy forward to lower brain structures until the energy in analyzed in the cortex of the brain.
Now, if anything is really magical, it’s this part of hearing. How does that electrical energy get processed into meaningful words and sentences? Researchers are just beginning to understanding how the brain works and new discoveries are revealing more and more amazing information every day.
Sound Traveled, Energy Converted, Hearing Accomplished
Hear that? Fast, wasn’t it?
To summarize, the sound energy from the air is captured by the ear, knocks on the ear drum, is amplified by the bones of the middle ear, swims into the waters of the inner ear where waves wash over tiny hairs, which snap an electrical message along nerve wiring to the brain. The energy zaps to the cortex where analysis takes place and a response unfolds next.
Although it happens in an instant, it’s not magic. But hearing is still rather miraculous … or magical … don’t you agree?
Learn more about hearing at How Stuff Works. If concerned about hearing loss, visit the Better Hearing Institute or Kids Health. Hearing loss has an educational impact on more that 8 percent of schoolchildren.
Reference: Martin, Frederick N. and Clark, John Greer (2009). Introduction to Hearing. Boston: Allyn and Bacon.
Sara E. Lewis - Sara E. Lewis is a writer and publications consultant. As a freelancer, she writes and produces marketing materials and especially enjoys ...
