Seashell resonance
Encyclopedia
Folklore
Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...
that if one holds a seashell
Seashell
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer created by an animal that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers...
—specifically, most often, a conch
Conch
A conch is a common name which is applied to a number of different species of medium-sized to large sea snails or their shells, generally those which are large and have a high spire and a siphonal canal....
shell—to one's ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
, one can hear the sound of the ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
.
The rushing sound that one hears is in fact the noise of the surrounding environment, resonating
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
within the cavity of the shell. The same effect can be produced with any resonant cavity, such as an empty cup or even by simply cupping one's hand over one's ear. The similarity of the noise produced by the resonator to that of the oceans is due to the resemblance between ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
movements and airflow.
The resonator is simply amplifying
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
some frequencies
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
of the ambient noise in the environment, including air flowing within the resonator and sound originating within the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
itself, and attenuating
Attenuation
In physics, attenuation is the gradual loss in intensity of any kind of flux through a medium. For instance, sunlight is attenuated by dark glasses, X-rays are attenuated by lead, and light and sound are attenuated by water.In electrical engineering and telecommunications, attenuation affects the...
others.
The human ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
picks up sounds made by the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
as well, including the sounds of blood flowing, muscles acting, and even air seeping through ear wax. These sounds are normally discarded by the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
; however, they become more obvious when louder external sounds are filtered out. This occlusion effect
Occlusion effect
The occlusion effect occurs when an object fills the outer portion of a person's ear canal, and that person perceives "hollow" or "booming" echo-like sounds of their own voice. It is caused by bone-conducted sound vibrations reverberating off the object filling the ear canal...
occurs with seashells, cups, or hands held over one's ears, and also with circum-aural headphones, whose cups form a seal around the ear, raising the acoustic
Acoustic
Acoustic may refer to:In science:* Acoustics, a branch of physics that studies sound** Musical acoustics, the branch of acoustics that studies the physics of music** Acoustic metamaterials, engineered materials with atypical properties...
impedance to external sounds.