As one of the five traditional senses, hearing, is a very important sense for humans to have. People who cannot hear have a condition of deafness. In the past, those who could not hear were often left out of conversations and other social situations.
Thankfully, over 100 years ago, with the advent of electricity, hearing aids were developed, giving those with hearing troubles a chance to regain their social position and overall enjoyment of life. The modern hearing aid is a superb device that is comfortable to wear, discerning in fashion, and provides the broadest technological rewards for wearers.
In order to understand what a hearing aid does for those with hearing difficulties, one must first picture how we hear. By looking at the physics of sound, the path of a sound wave, the anatomy of the human ear, differences in function between human ears and the ears of animals, hearing under different conditions, and choices to traditional hearing, one can understand the entire complicated process fairly easily.The Physics of Sound
Sound is transferred through every medium, including liquid, solid, plasma and gas. When carried through a solid, it is both a longitudinal wave and a transverse wave. However, when sound is transferred through the other mediums, it is only a longitudinal wave, also known as a compression wave. Longitudinal waves are areas of different pressure, deviating from the equilibrium pressure.
In order to classify a sound wave, they should be examined by the general properties of all waves.
Frequency
Wavelength
Period
Amplitude
Intensity
Speed
Direction
Sound travels quickly. Not nearly as fast as light, of course, but fast nonetheless. Sound travels through various mediums at various speeds, but this can always be measured by being proportional to the square root of the ratio of the stiffness of the medium to its density. Additionally, sound travels at different speeds due to the temperature of the medium. Here are a few examples.
In 20 degree freshwater, sound travels at 3,315 mph.
In steel, sound travels at 13,330 mph.
This is a significant difference in how sound behaves in various environments.
How loud something is can be referred to as intensity or volume, and volume is measured in a unit of measure named decibels. The significant decibel levels for those thinking about getting a hearing aid are transferred from common sources like a person talking or a TV that has been turned on. Here is a list of other sounds and decibel levels.
Normal conversation, 50 decibels
Traffic on a major thoroughfare, 90 decibels
Damage will occur if exposed to this level for a short time, 120 decibels
Damage to one's hearing is one of the few things which the human body cannot repair. Once some of the auditory nerves have been damaged, they are not put back or fixed.
For people, sound waves between the frequency range of 12Hz to 20,000Hz can be detected as sound. For animals, the range differs, with dogs being noted for their ability to hear things with a frequency above 20,000 Hz. The vibrations from a sound being created are picked up by the outer ear, and brought into the inner ear where the ear changes pressure waves into nerve impulses. These impulses are sent to the brain and comprehended as sound. A more in-depth knowledge can be gained by looking into the anatomy of the ear.
The process of receiving a sound wave to amplifying it to translating it into a form that the brain can understand is genuinely amazing. Hearing aids help the middle ear by inflating the signal enough for the inner ear to interpret it and send the message to the brain. When the brain receives these signals, it interprets them as the various sounds which we all know. The path of sound from source to the outer ear, middle ear, inner ear, and then brain where it is perceived as a sound is a long one. However, because speed travels extremely quickly, and the nerves in the ear receive and send the signal to the brain rapidly, what we see and what we hear are in sync.
If you have lost your hearing, hearing aids are excellent tools of our modern time which should be enjoyed.
