Ears

Did you hear that? What’s that rustling in the bushes? Is that a warbler in the distance? A plane taking off and then a jackhammer drown out other sounds. You slap the side of your head as the drone of a mosquito attracts your attention. Home from your walk, Beethoven’s 6th Symphony lulls you to sleep on the recliner. All these experiences may be very familiar but we have hardly a clue about what is really going on when we hear sounds. Air vibrations are detected, converted into hydro-dynamic vibrations and then into electrical impulses that reach the brain which evaluates and identifies what it hears. Amazing! How does that work? The level of technology involved is beyond what science has attained or in some aspects hasn’t even understood. Let’s take a peek at a few of the intricacies.

The outer ear on each side of our head captures the sound waves in the uniquely shaped grooves that funnel them into the ear canal along two paths, a shorter one directly to the canal and a longer path around the outer edge. That seems trivial but the net result is a cleverly designed, tiny split second difference in arrival and intensity at the ear drum on each side. From this the brain calculates the direction and approximate distance from which the sound comes. The two ‘sources’ on each side effectively create 4 ears. Wow!

In the middle ear area the drum vibrates and transfers air vibration energy to liquid vibrations. These liquid vibrations reach the 3 tiniest bones in the human body: hammer, anvil and stirrup. Together these weigh only 10 milligrams. Vibrational transfer from air to liquid usually means huge losses due to reflection or bounce at the surface. The energy level is already very small. But the middle ear has been created in such a way that there is nearly zero loss. The ear drum and middle ear bones exactly match the sound wave impedance. The oval window through which the waves travel is about 1/20 the size of the drum, concentrating the sound. The three bones further triple the amplification directed to the inner ear. And it gets even more complex.

In the inner ear the vibrations are changed into electrical neural impulses that travel to about 12,000 miniscule hair-like sensory cells lined up like piano keys. A piano has 88 keys. This apparatus has 12,000! It is not yet understood how this works. From there the auditory nerve transmits the message to the brain for interpretation, which is another wonder!!

There is much more detail in Dr. Werner Gitt’s book, “The Wonder of Man” to whom I am indebted for this information.

In summary, our larynx is built to produce sounds, our mouth and throat modulate them into usable vowels and consonants, and our brain controls and interprets the meaning of sounds that our ears have heard. Ps. 94:9 “Does He who implanted the ear not hear?” The Lord is very interested in hearing from each one of us, but even more interested in us listening to Him.

Listen for the sunny side, Henry Wiebe