Nature, Behavior, and Properties of Sound: Difference between revisions

Latest revision as of 21:17, 28 November 2015

Claimed and Created by Nadiya Zafar (nzafar7)

Sound is a Wave

https://www.youtube.com/watch?v=R6sSnMbPl5Q

https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/mechanical-waves/v/introduction-to-waves

Mechanical

A sound wave is a mechanical wave or medium (a series of interconnected or interacting particles) that carries a disturbance from one location to another, like air, water, or even metal. There is an original source of the wave, and then, the sound wave is moved to a new place by particle-to-particle interaction. "If the sound wave is moving through air, then as one air particle is displaced from its equilibrium position, it exerts a push or pull on its nearest neighbors, causing them to be displaced from their equilibrium position. This particle interaction continues throughout the entire medium, with each particle interacting and causing a disturbance of its nearest neighbors. Since a sound wave is a disturbance that is transported through a medium via the mechanism of particle-to-particle interaction, a sound wave is characterized as a mechanical wave." (Physics Classroom)

Longitudinal

https://www.youtube.com/watch?v=9LkLj8TS9VI

"Sound waves are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction that the sound wave moves. A vibrating string can create longitudinal waves. As it moves in the forward direction, it begins to push upon surrounding air molecules, moving them to the right towards their nearest neighbor. This causes the air molecules to the right of the string to be compressed into a small region of space. As the vibrating string moves in the reverse direction, it lowers the pressure of the air immediately to its right, thus causing air molecules to move back leftward. The lower pressure to the right of the string causes air molecules in that region immediately to the right of the string to expand into a large region of space. The back and forth vibration of the string causes individual air molecules (or a layer of air molecules) in the region immediately to the right of the string to continually vibrate back and forth horizontally. The molecules move rightward as the string moves rightward and then leftward as the string moves leftward. These back and forth vibrations are imparted to adjacent neighbors by particle-to-particle interaction. Other surrounding particles begin to move rightward and leftward, thus sending a wave to the right. Since air molecules (the particles of the medium) are moving in a direction that is parallel to the direction that the wave moves, the sound wave is referred to as a longitudinal wave. The result of such longitudinal vibrations is the creation of compressions and rarefactions within the air." (Physics Classroom)

Pressure

https://www.youtube.com/watch?v=8adOVT8UcTw

Sound waves are pressure waves because it consists of a repeating pattern of high-pressure and low-pressure regions moving through a medium. "If a detector, whether it is the human ear or a man-made instrument, were used to detect a sound wave, it would detect fluctuations in pressure as the sound wave impinges upon the detecting device. At one instant in time, the detector would detect a high pressure; this would correspond to the arrival of a compression at the detector site. At the next instant in time, the detector might detect normal pressure. And then finally a low pressure would be detected, corresponding to the arrival of a rarefaction at the detector site. The fluctuations in pressure as detected by the detector occur at periodic and regular time intervals. In fact, a plot of pressure versus time would appear as a sine curve. The peak points of the sine curve correspond to compressions; the low points correspond to rarefactions; and the "zero points" correspond to the pressure that the air would have if there were no disturbance moving through it." (Physics Classroom)

Behavior

https://www.youtube.com/watch?v=CDj_HRaGqp4

Reflection

https://www.youtube.com/watch?v=xnTAfCqzYZI

"Reflection of sound waves off of surfaces can lead to one of two phenomena - an echo or a reverberation. A reverberation often occurs in a small room with height, width, and length dimensions of approximately 17 meters or less. Why the magical 17 meters? The effect of a particular sound wave upon the brain endures for more than a tiny fraction of a second; the human brain keeps a sound in memory for up to 0.1 seconds. If a reflected sound wave reaches the ear within 0.1 seconds of the initial sound, then it seems to the person that the sound is prolonged. The reception of multiple reflections off of walls and ceilings within 0.1 seconds of each other causes reverberations - the prolonging of a sound. Since sound waves travel at about 340 m/s at room temperature, it will take approximately 0.1 s for a sound to travel the length of a 17 meter room and back, thus causing a reverberation (recall from Lesson 2, t = d/v = (34 m)/(340 m/s) = 0.1 s). This is why reverberations are common in rooms with dimensions of approximately 17 meters or less. Perhaps you have observed reverberations when talking in an empty room, when honking the horn while driving through a highway tunnel or underpass, or when singing in the shower. In auditoriums and concert halls, reverberations occasionally occur and lead to the displeasing garbling of a sound." (Physics Classroom)

Refraction

https://www.youtube.com/watch?v=UR2rjO0TkU0

"Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So if the media (or its properties) are changed, the speed of the wave is changed. Thus, waves passing from one medium to another will undergo refraction. Refraction of sound waves is most evident in situations in which the sound wave passes through a medium with gradually varying properties. For example, sound waves are known to refract when traveling over water. Even though the sound wave is not exactly changing media, it is traveling through a medium with varying properties; thus, the wave will encounter refraction and change its direction. Since water has a moderating effect upon the temperature of air, the air directly above the water tends to be cooler than the air far above the water. Sound waves travel slower in cooler air than they do in warmer air. For this reason, the portion of the wavefront directly above the water is slowed down, while the portion of the wavefronts far above the water speeds ahead. Subsequently, the direction of the wave changes, refracting downwards towards the water." (Physics Classroom)

Diffraction

https://www.youtube.com/watch?v=GgxcvflVxDM

"Diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path. The amount of diffraction (the sharpness of the bending) increases with increasing wavelength and decreases with decreasing wavelength. In fact, when the wavelength of the wave is smaller than the obstacle or opening, no noticeable diffraction occurs. Diffraction of sound waves is commonly observed; we notice sound diffracting around corners or through door openings, allowing us to hear others who are speaking to us from adjacent rooms. Many forest-dwelling birds take advantage of the diffractive ability of long-wavelength sound waves. Owls for instance are able to communicate across long distances due to the fact that their long-wavelength hoots are able to diffract around forest trees and carry farther than the short-wavelength tweets of songbirds. Low-pitched (long wavelength) sounds always carry further than high-pitched (short wavelength) sounds." (Physics Classroom)

Connectedness

I am majoring in biochemistry with a minor in Health, Medicine, and Society, and I wish to enter the medicinal field. Sound and vibrations are not only used as a diagnostic tool in primary care physicians offices for lung and bone cavity analysis, but the fundamental concepts of them are also used in creating medical devices such as ultrasound technology for imaging of early fetus development.

@@ Line 1: / Line 1: @@
-Claimed by Nadiya Zafar
+Claimed and Created by Nadiya Zafar (nzafar7)
-==Sound is a WAVE==
+==Sound is a Wave==
-This topics focuses on energy work of a system but it can only deal with a large scale response to heat in a system.  '''Thermodynamics''' is the study of the work, heat and energy of a system.  The smaller scale gas interactions can explained using the kinetic theory of gases.  There are three fundamental laws that go along with the topic of thermodynamics.  They are the zeroth law, the first law, and the second law.  These laws help us understand predict the the operation of the physical system.  In order to understand the laws, you must first understand thermal equilibrium.  [[Thermal equilibrium]] is reached when a object that is at a higher temperature is in contact with an object that is at a lower temperature and the first object transfers heat to the latter object until they approach the same temperature and maintain that temperature constantly.  It is also important to note that any thermodynamic system in thermal equilibrium possesses internal energy.
+https://www.youtube.com/watch?v=R6sSnMbPl5Q
+https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/mechanical-waves/v/introduction-to-waves
 ===Mechanical===
-The zeroth law states that if two systems are at thermal equilibrium at the same time as a third system, then all of the systems are at equilibrium with each other.  If systems A and C are in thermal equilibrium with B, then system A and C are also in thermal equilibrium with each other.  There are underlying ideas of heat that are also important.  The most prominent one is that all heat is of the same kind.  As long as the systems are at thermal equilibrium, every unit of internal energy that passes from one system to the other is balanced by the same amount of energy passing back.  This also applies when the two systems or objects have different atomic masses or material.
+A sound wave is a mechanical wave or medium (a series of interconnected or interacting particles) that carries a disturbance from one location to another, like air, water, or even metal. There is an original source of the wave, and then, the sound wave is moved to a new place by particle-to-particle interaction. "If the sound wave is moving through air, then as one air particle is displaced from its equilibrium position, it exerts a push or pull on its nearest neighbors, causing them to be displaced from their equilibrium position. This particle interaction continues throughout the entire medium, with each particle interacting and causing a disturbance of its nearest neighbors. Since a sound wave is a disturbance that is transported through a medium via the mechanism of particle-to-particle interaction, a sound wave is characterized as a mechanical wave." (Physics Classroom)
 ====Longitudinal====
-If A = B and A = C, then B = C
+https://www.youtube.com/watch?v=9LkLj8TS9VI
-A = B = C
+"Sound waves are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction that the sound wave moves. A vibrating string can create longitudinal waves. As it moves in the forward direction, it begins to push upon surrounding air molecules, moving them to the right towards their nearest neighbor. This causes the air molecules to the right of the string to be compressed into a small region of space. As the vibrating string moves in the reverse direction, it lowers the pressure of the air immediately to its right, thus causing air molecules to move back leftward. The lower pressure to the right of the string causes air molecules in that region immediately to the right of the string to expand into a large region of space. The back and forth vibration of the string causes individual air molecules (or a layer of air molecules) in the region immediately to the right of the string to continually vibrate back and forth horizontally. The molecules move rightward as the string moves rightward and then leftward as the string moves leftward. These back and forth vibrations are imparted to adjacent neighbors by particle-to-particle interaction. Other surrounding particles begin to move rightward and leftward, thus sending a wave to the right. Since air molecules (the particles of the medium) are moving in a direction that is parallel to the direction that the wave moves, the sound wave is referred to as a longitudinal wave. The result of such longitudinal vibrations is the creation of compressions and rarefactions within the air." (Physics Classroom)
 ====Pressure====
-How do we visualize or predict using this topic. Consider embedding some vpython code here [https://trinket.io/glowscript/31d0f9ad9e Teach hands-on with GlowScript]
+https://www.youtube.com/watch?v=8adOVT8UcTw
-==Properties and Perception==
-The first law of thermodynamics defines the internal energy (E) as equal to the difference between heat transfer (Q) ''into'' a system and work (W) ''done by'' the system.  Heat removed from a system would be given a negative sign and heat applied to the system would be given a positive sign.  Internal energy can be converted into other types of energy because it acts like potential energy.  Heat and work, however, cannot be stored or conserved independently because they depend on the process.  This allows for many different possible states of a system to exist.  There can be a process known as the adiabatic process in which there is no heat transfer.  This occurs when a system is full insulated from the outside environment.  The implementation of this law also brings about another useful state variable, '''enthalpy'''.
+Sound waves are pressure waves because it consists of a repeating pattern of high-pressure and low-pressure regions moving through a medium. "If a detector, whether it is the human ear or a man-made instrument, were used to detect a sound wave, it would detect fluctuations in pressure as the sound wave impinges upon the detecting device. At one instant in time, the detector would detect a high pressure; this would correspond to the arrival of a compression at the detector site. At the next instant in time, the detector might detect normal pressure. And then finally a low pressure would be detected, corresponding to the arrival of a rarefaction at the detector site. The fluctuations in pressure as detected by the detector occur at periodic and regular time intervals. In fact, a plot of pressure versus time would appear as a sine curve. The peak points of the sine curve correspond to compressions; the low points correspond to rarefactions; and the "zero points" correspond to the pressure that the air would have if there were no disturbance moving through it." (Physics Classroom)
 ==Behavior==
-E2 - E1 = Q - W
+https://www.youtube.com/watch?v=CDj_HRaGqp4
 ===Reflection===
+https://www.youtube.com/watch?v=xnTAfCqzYZI
+"Reflection of sound waves off of surfaces can lead to one of two phenomena - an echo or a reverberation. A reverberation often occurs in a small room with height, width, and length dimensions of approximately 17 meters or less. Why the magical 17 meters? The effect of a particular sound wave upon the brain endures for more than a tiny fraction of a second; the human brain keeps a sound in memory for up to 0.1 seconds. If a reflected sound wave reaches the ear within 0.1 seconds of the initial sound, then it seems to the person that the sound is prolonged. The reception of multiple reflections off of walls and ceilings within 0.1 seconds of each other causes reverberations - the prolonging of a sound. Since sound waves travel at about 340 m/s at room temperature, it will take approximately 0.1 s for a sound to travel the length of a 17 meter room and back, thus causing a reverberation (recall from Lesson 2, t = d/v = (34 m)/(340 m/s) = 0.1 s). This is why reverberations are common in rooms with dimensions of approximately 17 meters or less. Perhaps you have observed reverberations when talking in an empty room, when honking the horn while driving through a highway tunnel or underpass, or when singing in the shower. In auditoriums and concert halls, reverberations occasionally occur and lead to the displeasing garbling of a sound." (Physics Classroom)
 ===Refraction===
-#How is this topic connected to something that you are interested in?
-#How is it connected to your major?
+https://www.youtube.com/watch?v=UR2rjO0TkU0
-#Is there an interesting industrial application?
+"Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So if the media (or its properties) are changed, the speed of the wave is changed. Thus, waves passing from one medium to another will undergo refraction. Refraction of sound waves is most evident in situations in which the sound wave passes through a medium with gradually varying properties. For example, sound waves are known to refract when traveling over water. Even though the sound wave is not exactly changing media, it is traveling through a medium with varying properties; thus, the wave will encounter refraction and change its direction. Since water has a moderating effect upon the temperature of air, the air directly above the water tends to be cooler than the air far above the water. Sound waves travel slower in cooler air than they do in warmer air. For this reason, the portion of the wavefront directly above the water is slowed down, while the portion of the wavefronts far above the water speeds ahead. Subsequently, the direction of the wave changes, refracting downwards towards the water." (Physics Classroom)
 ===Diffraction===
+https://www.youtube.com/watch?v=GgxcvflVxDM
+"Diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path. The amount of diffraction (the sharpness of the bending) increases with increasing wavelength and decreases with decreasing wavelength. In fact, when the wavelength of the wave is smaller than the obstacle or opening, no noticeable diffraction occurs. Diffraction of sound waves is commonly observed; we notice sound diffracting around corners or through door openings, allowing us to hear others who are speaking to us from adjacent rooms. Many forest-dwelling birds take advantage of the diffractive ability of long-wavelength sound waves. Owls for instance are able to communicate across long distances due to the fact that their long-wavelength hoots are able to diffract around forest trees and carry farther than the short-wavelength tweets of songbirds. Low-pitched (long wavelength) sounds always carry further than high-pitched (short wavelength) sounds."
+(Physics Classroom)
+==Connectedness==
+I am majoring in biochemistry with a minor in Health, Medicine, and Society, and I wish to enter the medicinal field. Sound and vibrations are not only used as a diagnostic tool in primary care physicians offices for lung and bone cavity analysis, but the fundamental concepts of them are also used in creating medical devices such as ultrasound technology for imaging of early fetus development.
+== See Also ==
+Doppler Effect
+Frequency
+Harmonics
+Vibration
+Resonance
+Intensity
+Standing Wave Patterns
+Open and Closed Air Columns
+===Further Reading===
+http://physics.info/sound/
+http://method-behind-the-music.com/mechanics/physics/
+https://www.khanacademy.org/science/physics/mechanical-waves-and-sound
+===External Links===
+https://www.youtube.com/watch?v=R6sSnMbPl5Q
-== See also ==
+https://www.youtube.com/watch?v=9LkLj8TS9VI
-Are there related topics or categories in this wiki resource for the curious reader to explore?  How does this topic fit into that context?
+https://www.youtube.com/watch?v=xnTAfCqzYZI
-===Further reading===
+https://www.youtube.com/watch?v=UR2rjO0TkU0
-Books, Articles or other print media on this topic
+https://www.youtube.com/watch?v=GgxcvflVxDM
-===External links===
+https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/mechanical-waves/v/introduction-to-waves
-Internet resources on this topic
+https://www.youtube.com/watch?v=8adOVT8UcTw
 ==References==
@@ Line 55: / Line 95: @@
 http://www.physicsclassroom.com/class/sound
-[[Category:Which Category did you place this in?]]
+[[Category: Sound]]

Nature, Behavior, and Properties of Sound: Difference between revisions

Latest revision as of 21:17, 28 November 2015

Contents

Sound is a Wave

Mechanical

Longitudinal

Pressure

Behavior

Reflection

Refraction

Diffraction

Connectedness

See Also

Further Reading

External Links

References

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