Our sense organs 45

The ear
– our highest-precision
sense organ
Without the sense of hearing we would lack an
important method of orientation. Like a bird in
a small cage, we would then be largely excluded
from everyday events,. Sounds intensify the sensory
impressions of life. We can listen to the murmur
of rippling wavelets at our feet, while at the
same time hearing the booming of the mighty
breakers rolling in from the ocean. When taking
a stroll, we enjoy the humming of bees flitting
from blossom to blossom, as well as the exuberant
song of a lark. We can hear a wide range of sounds,
from the soft whining of a mosquito to the earshattering
noise of a jet plane taking off. The racket
of pneumatic drills and other noisy machines
are also part of our everyday experience. Although
these sound signals reveal their origin, they do not
convey any personal messages to us.
no science has as yet been able to attain, or even
(in many aspects) to understand? For the purpose
of describing this, we need a few technical terms,
which will first be explained:
Sound level: Vibrating objects (like a tuning fork,
the cone of a loudspeaker, or human vocal
chords) induce vibrations in the surrounding air.
Adjacent air molecules are accelerated, causing
waves travelling at a speed of approximately
330 m/s. This phenomenon is called sound, and
in a sound field there are zones where air molecules
are more densely packed than in other
zones. Air pressure is greater in the denser zones,
and smaller in the less dense zones. Sound vibrations
can be depicted as wave-shaped graphs.
The distance between two adjacent locations
where the air pressure is the same, is known as
the wave length. The maximum deviation from
the neutral value is called the amplitude. If the
wave length increases (implying a decrease in the
number of vibrations per time unit), the pitch of
the sound becomes lower. And, vice versa, when
In addition to receiving sounds, we can also
transmit them. Speaking and hearing comprise
our basic method of communication. In this case
the kinds of noises and their significance are
completely different. Musical notes, songs, and
the spoken word bear meaningful messages. The
act of identifying their inherent meaning involves
much more than merely processing the received
sound waves. A special evaluation system, located
in the brain, is required for this purpose.
Without the brain we would not have been able
to hear. Our souls are stirred by what we hear, as
expressed by the poignant French proverb: “The
ear is the way to the heart.”
In our contact with the world our sense of hearing
is just as important as our vision. Sounds are air
vibrations which are detected by our ears, where
they are first converted into hydro-dynamic vibrations,
and subsequently into electrical nerve
impulses. Finally the brain identifies these signals
as information.
Did you know that the human ear is a detection
device which utilises a level of technology that
The curved rim
of the helix forms
a tunnel or flume
The root of the
helix (Crus helicus)
Concealed opening
of the external
acoustic meatus
Lid of the ear (Tragus)
Antitragus
Concha (a hollow depression)
Antihelix
Helix
Gateway to the flume of the helix
Darwin's tubercle
21