Resonance
RESONANCE: " The property whereby any vibratory system responds with
maximum amplitude to an applied force having the a frequency equal to its
own."
In english, this means that any solid object that is struck with a sound
wave of equal sound wave vibrations will amplitude the given tone. This
would explain the reason why some singers are able to break wine glasses
with their voice. The vibrations build up enough to shatter the glass. This is
called RESONANCE.
Resonance can be observed on a tube with one end open. Musical tones
can be produces by vibrating columns of air. When air is blown across the
top of the open end of a tube, a wave compression passes along the tube.
When it reaches the closed end, it is reflected. The molecules of reflected air
meet the molecules of oncoming air forming a node at the closed end. When
the air reaches the open end, the reflected compression wave becomes a
rarefaction. It bounces back through the tube to the closed end, where it is
reflected. the wave has now completed a single cycle. It has passed through
the tube four times making the closed tube, one fourth the length of a sound
wave. By a continuous sound frequency, standing waves are produced in the
tube. This creates a pure tone.
We can use this knowledge of one fourth wavelength to create our own
demonstration. It does not only have to be done using wind, but can also be
demonstrated using tuning forks. If the frequency of the tuning forks is
known, then v=f(wavelength) can find you the length of your air column.
Using a tuning fork of frequency 512 c/s, and the speed of sound is
332+0.6T m/s, temperature being, 22 degrees, substitute into the formula.
Calculate 1/4 wavelength
V=f(wavelength)
wavelength=V/f
=345.2 (m/s) / 512 (c/s)
=0.674 m/c
1/4 wave. =0.674 (m/c) / 4
= 0.168 m/c
Therefore the pure tone of a tuning fork with frequency 512 c/s in a
temperature of 22 degrees would be 16.8 cm. The pure tone is C.
If this was done with other tuning forks with frequencies of 480, 426.7,
384, 341.3, 320, 288, and 256 c/s then a scale in the key of C would be
produced.
There are many applications of this in nature. One example of this would
be the human voice. Our vocal chords create sound waves with a given
frequency, just like the tuning fork.
One of the first applications of the wind instrument was done in ancient
Greece where the pipes of pan were created. pipes of hollow reeds were
bound together, all of different length. When Pan, the god of fields, blew
across his pipes, the tones of a musical scale were heard. Later reproduction
of the same type were created and musical instruments are heard all over the
world thanks to the law of resonation.
Bibliography
Granet, Charles; Sound and Hearing; Abelard-Schuman, Toronto; 1965
Freeman, Ira M.; Sound and Ultrasonics; Random House; New york; 1968
Freeman, Ira M.; Physics Made Simple; Doubleday, New York; 1965
Jones, G.R.; Acoustics; English Univ. Press; London; 1967
White, Harvey E; Physics and Music; Saunders College, Philadelphia; 1980
Funk and Wagnall; Standard Desk Dictionary; Harper Row, USA; 1985
Resonance
RESONANCE: " The property whereby any vibratory system responds with
maximum amplitude to an applied force having the a frequency equal to its
own."
In english, this means that any solid object that is struck with a sound
wave of equal sound wave vibrations will amplitude the given tone. This
would explain the reason why some singers are able to break wine glasses
with their voice. The vibrations build up enough to shatter the glass. This is
called RESONANCE.
Resonance can be observed on a tube with one end open. Musical tones
can be produces by vibrating columns of air. When air is blown across the
top of the open end of a tube, a wave compression passes along the tube.
When it reaches the closed end, it is reflected. The molecules of reflected air
meet the molecules of oncoming air forming a node at the closed end. When
the air reaches the open end, the reflected compression wave becomes a
rarefaction. It bounces back through the tube to the closed end, where it is
reflected. the wave has now completed a single cycle. It has passed through
the tube four times making the closed tube, one fourth the length of a sound
wave. By a continuous sound frequency, standing waves are produced in the
tube. This creates a pure tone.
We can use this knowledge of one fourth wavelength to create our own
demonstration. It does not only have to be done using wind, but can also be
demonstrated using tuning forks. If the frequency of the tuning forks is
known, then v=f(wavelength) can find you the length of your air column.
Using a tuning fork of frequency 512 c/s, and the speed of sound is
332+0.6T m/s, temperature being, 22 degrees, substitute into the formula.
Calculate 1/4 wavelength
V=f(wavelength)
wavelength=V/f
=345.2 (m/s) / 512 (c/s)
=0.674 m/c
1/4 wave. =0.674 (m/c) / 4
= 0.168 m/c
Therefore the pure tone of a tuning fork with frequency 512 c/s in a
temperature of 22 degrees would be 16.8 cm. The pure tone is C.
If this was done with other tuning forks with frequencies of 480, 426.7,
384, 341.3, 320, 288, and 256 c/s then a scale in the key of C would be
produced.
There are many applications of this in nature. One example of this would
be the human voice. Our vocal chords create sound waves with a given
frequency, just like the tuning fork.
One of the first applications of the wind instrument was done in ancient
Greece where the pipes of pan were created. pipes of hollow reeds were
bound together, all of different length. When Pan, the god of fields, blew
across his pipes, the tones of a musical scale were heard. Later reproduction
of the same type were created and musical instruments are heard all over the
world thanks to the law of resonation.
Bibliography
Granet, Charles; Sound and Hearing; Abelard-Schuman, Toronto; 1965
Freeman, Ira M.; Sound and Ultrasonics; Random House; New york; 1968
Freeman, Ira M.; Physics Made Simple; Doubleday, New York; 1965
Jones, G.R.; Acoustics; English Univ. Press; London; 1967
White, Harvey E; Physics and Music; Saunders College, Philadelphia; 1980
Funk and Wagnall; Standard Desk Dictionary; Harper Row, USA; 1985
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