How we Hear
Understand Ear and Sound
Human beings have five senses. Every sense receptor is a complex piece of bioengineering. This natural marvel does not have a manmade or mechanical counterpart. It receives and converts sounds of nature, music, conversations with family and friends, etc. into legible sounds that we can relate to.
Additionally, human ears act as a natural warning system. It is capable of identifying oncoming traffic, processing a possible break-in, alerting when there are other possible dangers, etc. Thus, hearing is a critical human sense and we must not wait until we experience hearing loss in order to remind us about its importance.
Life is not worth living without the sounds and voices that matter!
The human ear has three parts:
- The outer ear (pinna, ear canal and eardrum)
- The middle ear (the ossicular chain)
- The inner ear (semicircular canal cochlea)
The outer ear collects the sound waves and transmits them towards the eardrum, or tympanum. The tympanum vibrates and these vibrations are carried inside and amplified further by the ossicular chain. Further amplification takes place in the inner ear and the sensations are taken to the brain for analysis.
Sound waves are like ripples created on a pond’s surface when it is disturbed by a stone. Sound waves, like ripples, move out as differences occur in air pressure (compressed air and rarefied air). When these fluctuations hit the eardrum, they manifest as sound.
Sound travels as waves of pressure through air at a speed of 740 miles (approx. 1184 km) per hour. There are two features of sound that we can measure — pitch and intensity.
Pitch, also known as frequency, is a measure of how rapidly the waves change from above to below the ambient pressure. In other words, it is a measure of how many crests pass a point in a second. The greater the number, the higher is the pitch.
Intensity (loudness or amplitude) is a measure of how far the waves are above or below the ambient pressure. The greater the amplitude, the louder is the sound. Pressure levels of sound are measured as decibels (dB).