What is Sound wave: Definition and 204 Discussions

In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the reception of such waves and their perception by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimetres (0.67 in). Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges.

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  1. Erenjaeger

    Please help, stuck -- Standard error in speed of sound wave....

    https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xfa1/v/t34.0-12/13100972_1004336679646107_71786442_n.png?oh=c0e0ad9cf30125d301d2069c6402b621&oe=57222F24&__gda__=1461854936_dad2ac5d3bd3a844b9428cd47c7dc733 Not sure if this counts as "advanced physics homework" but can someone please help me...
  2. F

    Observing the Effects of Sound Wave Diffraction: A Demonstration Experiment

    Homework Statement Write an experiment to demonstrate the diffraction of a sound wave and specify what has to observe to conclude that wave has been diffracted Homework EquationsThe Attempt at a Solution I know that we've to create diffraction by using a speaker and a slit and a microphone...
  3. steven george

    I Frequencies of standing waves in a straw

    I am a physics teacher and I my class is currently studying sound waves. I had my class make some noise makers with straws as shown here. http://www.physics.org/interact/physics-to-go/straw-oboes/ We measured the frequencies coming from the straws and they seem to act like a pipe open at...
  4. B

    What is the smallest frequency difference that can be detected by the human ear?

    Homework Statement Consider two sound sources S1 with a frequency of f1 = 3367 Hz and S2 with a frequency of f2 = 3362 Hz. Determine the smallest difference in frequency from 3367 Hz that the average person can detect? Homework Equations The only thing I can think of is approximating the...
  5. darkmamon

    What happens when sound wave loses energy?

    I'm a high school student doing the project about sound absorbing material When the sound is absorbed or loses its energy which of its value will change? pressure? wavelength? or frequency? (at first I though that the sound wave will just lose its amplitude but after the result,It look like its...
  6. rpthomps

    How long would it take a sound wave to travel 150m

    Homework Statement The sound speed in air at 0 degrees Celsius is 331 m/s, and for temperatures within a few tens of degrees of 0 degrees celsius it increases at the rate 0.590 m/s for every degree celsius increase in temperature. How long would it take a sound wave to travel 150 m over a path...
  7. R

    Can a sound wave be both standing and traveling?

    Apologies if this is a stupid question, I have a reference that says: "An ultrasonic field will be a combination of standing and traveling waves. An increase in the traveling wave will decrease the proportion of a standing wave and vica versa". I'm trying to visualise this, I understand the...
  8. R

    Relating Power output of a sound wave to the pressure....

    ... it's amplitude exerts. During cavitation a sound wave is applied to a liquid and breaks it apart and gas pockets are formed. The frequency and the amplitude of the sound wave effect the bubble/s. My question is, if I have the power output of the device then how would this relate to the...
  9. A

    Hearing a Sound Wave: Does Intensity Matter?

    Does the ability of an observer to hear a sound wave depends solely upon the intensity of the sound wave?
  10. Mnemonic

    Power of Sound Wave at distance

    Homework Statement A sound source is placed at the top of a (h = 121.5m) radio tower. The source has a frequency of 653.8 Hz and an amplitude of 11.4 nm at point A. The air surrounding the tower has a density of 1.32 kgm-3 and sound travels through it with a velocity of 340 ms-1. Point A is...
  11. M

    Measuring distance a sound wave travels

    I would like to be able to measure the distance a sound wave travels. This is for a violin bridge and what I would like to do is apply a frequency corresponding to the frequency the string (196 hz for the g string) and determine the distance the wave traveled to get to the foot of the bridge...
  12. O

    What happens to the sound wave?

    Ok so it happened again... my students asked a question I hand't thought of before (love it when that happens!) Can you help me? What happens to the sound wave after it hits the eardrum? Does it get absorbed, or does it continue to go through your head? I found lots of info about how the...
  13. U

    How Do Velocity and Pressure Relate in Linear Sound Wave Equations?

    Taken from my lecturer's notes, how did they make the jump from 8.5 to 8.6 and 8.7? Even after differentiating (8.5) with time I get \rho_0 \frac{\partial^2 \vec u'}{\partial t^2} + \nabla \frac{\partial p '}{\partial t} = 0 \frac{\partial^2 p'}{\partial t^2} + \rho_0 c^2 \nabla \cdot...
  14. jerromyjon

    Sound wave propagation and doppler shift wrt the medium

    In contemplation and research regarding another thread's question about the asymmetry of doppler shift wrt the medium, I find myself trying to imagine two people talking... or perhaps better yet matching pitch. In still air with both people facing each other at ten paces of course they would...
  15. M

    Instantaneous Displacement of a Sound Wave

    Homework Statement A sinusoidal sound wave moves through a medium and is described by the displacement wave function s(x,t) = 2.00cos(15.7x - 858t) where s is in micrometers, x is in meters, and t is in seconds. Find a) the amplitude, b) the wavelength, and c) the speed of this wave. D)...
  16. C

    Calculate Intensity of Sound Waves at 3.0 m from Source

    Homework Statement A small source emits sound waves with a power output 80W. a) find the intensity at a point 3.0m from the source. (0.71W/m) b) find the intensity level at the same point as part a.(118.51) c) at what distance would the intensity be one-fourth as much as of that part (a). i...
  17. A

    Sound wave inside a closed cylinder - Bessel function

    Homework Statement The question is as follows, there is a cylinder with length L and radius R, there is a sound wave with a phase velocity v, they ask for the normal modes and the 5 lowest frequencies when L=R Homework Equations Wave equation for 3D, (d^2/dt^2)ψ=v^2*(∇^2)ψ The Attempt at a...
  18. S

    Sound waves and Harmonics help

    Hello, I am having a hard time solving this question. Any help is really appreciated. 1. Homework Statement You have designed a new musical instrument of very simple construction. Your design consists of a metal tube with length L and diameter L/10. You have stretched a string of mass per...
  19. SalfordPhysics

    Helmholtz Resonator using voltmeter

    Hi, I am trying to understand how precisely a voltmeter is used to measure the resonant frequency of a sound wave in a helmholtz resonator. Is it simply that the maximum voltage corresponds to the resonant frequency? A detailed description or external link would be great. Many thanks.
  20. PeSoberbo

    What is the Second Step in Feynman's Deduction of the Sound Wave Equation?

    I am studying the sound wave equation deducted by Feynman in his lectures. In section 47-3: P0 + Pe = f(d0 + de) = f(d0) + de f'(d0) Where f'(d0) stands for the derivative of f(d) evaluated at d=d0. Also, de is very small. I do not understand the second step of the equality. Can anyone help...
  21. H

    For a sound wave how/why does the compression and rarefaction occur?

    I cannot seem to visualize how this compression and rarefaction occurs for example when I clap my hands, I know I move air molecules away from me, but it's so weird that such compression(high air pressure) and rarefaction(low air pressure) occurs. I also do not quite understand why this...
  22. S

    Are the wavelength of standing wave and sound wave produced same?

    Homework Statement a string is tightened at 2 ends. the string is then plucked , a standing wave is produced. are the wavelength of standing wave and sound wave produced same? Homework Equations The Attempt at a Solution
  23. S

    Grpah of l versus 1/f (sound wave)

    Homework Statement to determine the c(end correction ) of sound wave of single end closed tube, the equtaion l +c= (lambda/4 ) is used , i don't understand the gradient is v/4 , then how does the author come up with the speed of sound in air is v=4 ? Homework Equations The Attempt...
  24. davidbenari

    Forming a standing sound wave in a wind instrument

    So I've had this question bugging me ever since I saw sound at physics class: How is it possible to match the resonance frequency of a column of air in an organ pipe and form a standing sound wave by simply blowing air into the column? The main reason I see this problematic is because I...
  25. K

    Equation of variation of displacement and pressure of sound wave

    Homework Statement i have attached the notes from 2 books below, i know that the graph of pressure of sound waves lag behind the displacement grpah by 90 degree. so it should be p=p max sin (wt-kx-(pi/2)) am i right? why the another book gives p=p max sin (wt-kx+(pi/2)) ? which is correct...
  26. C

    Intensity of a sound wave problem

    Homework Statement Two loudspeakers are placed beside each other and produce sound of the same intensity at the position of a listener. One speaker produces a low note of 40 Hz and the other produces a high note of 2560 Hz. What is the ratio of the maximum displacements of the speakers...
  27. Saitama

    Solve Sound Wave Problem: Frequency of Sound in Air (336 m/s)

    Homework Statement A source of sound S and a detector D are placed at some distance from one another. A big cradboard is placed near the detector and perpendicular to line SD as shown in figure. It is gradually moved away and it is found that the intensity changes from a maximum to a minimum as...
  28. jerry0696

    Is sound wave a transverse wave?

    i had always belived that sound wave was a longitudinal wave till i come across something saying that its a transverse wave in solid.can anyone explain is it so??
  29. S

    Sound Wave Attenuation: Why Does Water Attenuate More?

    Why does water attenuate sound waves more than air? Is it because of it's bulk modulus? This is what I understand. Speed through a medium is determined by the elastic component over the inertial component. Since water has a much greater bulk modulus (elastic component) than air, it makes the...
  30. A

    How Do Different Aperture Shapes in a Styrofoam Box Affect Wave Harmonics?

    I did an experiment for school, and I put a speaker in a styrofoam box with a rectangle cut out of the front. I had styrofoam bricks that fit perfectly in the hole, each with a hole cut out. The hole shape differed, with things like a funnel, a diagonal line, a circle, a square, etc. I was...
  31. W

    Sound Wave, Microphone and Electromagnetic Induction

    Dear all, I have encountered an issue in understanding how microphone works and I hope you guys can assist. There are two scenarios involved. In the first scenario, there is tuning fork and a microphone. The microphone contains a small disc attached to a magnet and a fixed coil. (Please...
  32. G

    Speed of sound wave and particle velocity

    This may be fairly straightforward but it is a concept that I am really having problems understanding. A sound wave is a pressure disturbance that travels through a medium by means of particle to particle interaction, so why is the wave velocity so much faster than the velocity of the particles...
  33. J

    What does a sound wave amplitude physically consist of?

    Frequency is pitch. Or how fast it oscillates. So what does the amplitude translate to in physical space? I know its volume, or the amount of energy. But what does it actually do to the air when you increase the amplitude?
  34. S

    Sound wave vs light wave speed

    Why do sound waves travel faster in incompressible material (such as water (water vs air)) and why do light waves travel faster in less dense (such as air (air vs water))? I know that sound waves are longitudinal waves and light waves are transverse waves. What is the relationship between...
  35. B

    Velocity of two different species in a gas with propagating sound wave

    I have a theoretical question which I would like to brainstorm, and would appreciate any assistance. Let's say sound waves are propagated through a gas, with two types of atoms with very different mass, different by say a factor of ten. The number of particles per unit volume is equal, as are...
  36. C

    Intensity of sound wave & energy passes into ear

    Homework Statement Please refer to the image. Question (a). Homework Equations I= P/(4∏r^2) P=E/t The Attempt at a Solution After a few attempts, I found the way to get the answer: (6.3 x 10^-6) x (1.5 x 10^-4) x 60 = 5.67 x 10^-8 But I don't understand why the area of...
  37. N

    Sound Wave Scattering: Interface Total Potential?

    Consider a plane sound wave (\varphi^i) incident up on a solid object . The object will scatter this incident wave. Let this scattered wave pass through an interface separating two different fluids (say with sound speeds c1 and c2). Now at the interface, is the scattered velocity potential...
  38. PhizKid

    Time between sound wave displacements

    Homework Statement Homework Equations The Attempt at a Solution So I set up: 2.0 nm = (6.0 nm)cos(kx + (3000 rad/s)t1 + phi) -2.0 nm = (6.0 nm)cos(kx + (3000 rad/s)t2 + phi) My professor said if there's a phi you can usually ignore it so I'm just going to remove them: 2.0...
  39. D

    Does the single diffraction work for sound wave

    PIC (A) http://imageshack.us/a/img37/941/img20130104192537.th.jpg PIC (B) http://imageshack.us/a/img23/5496/img20130104192554.th.jpg I hope you can ans it in a simple way as I am just a secondary 6 student :) thx! For pic a, 1. I dun understand why interference occurs when there is 1 slit...
  40. W

    Finding the strongest beat in a sound wave using autocorrelation

    Hi everyone, I have a sound wave representing a piano piece played at a steady tempo, and would like to get a graph of the saliency of each beat (essentially, a probability distribution for how strong each possible tempo is). I understand that this is done by plotting the autocorrelation...
  41. K

    Is it possible to split water with sound wave?

    I have been researching about splitting water including electrolysis, but I came across about using ultrasonic sound wave to split water, I search around and it said that water will decompose at 42000 hertz, is this true, because I am going to do it for my project. May anyone please give me a...
  42. R

    Travel Sound Wave: Determine Wavelength, Frequency, etc.

    Homework Statement A traveling sound wave is represented by D(x,t)=0.48sin(5.6x+84t) with D in meter and t in seconds. Determine wavelength, frequency, amplitude, velocity (including direction) and the maximum speed of the vibrating air. Homework Equations Okay, I'm quite confused about...
  43. N

    What is the Frequency of the Sound Wave Produced by a Vibrating Guitar String?

    Homework Statement One of the 63.5-cm-long strings of an ordinary guitar is tuned to produce the note B3 (frequency 245 Hz) when vibrating in its fundamental mode. A) Find the speed of transverse waves on this string. B) If the tension in this string is increased by 1.0%, what will be...
  44. D

    Sound wave interference destructive interference problem?

    Homework Statement Two identical loud speakers placed at A and B 2m apart produce sound waves of frequency 440 HZ and with a velocity 320 m/sec a small microphone was used and placed at C along a perpendicular line from AB if there will be a destructive interference at C find the length of...
  45. D

    Why are the products of sound wave lengths and frequencies always constant?

    Hi everyone! I was reading a textbook a while ago about waves and it had just finished talking about wave speeds and how it is the product of the frequency times the wave length. On the next page, it gave a table of frequencies and wave lengths of sound waves and how their products are all...
  46. R

    'Doppler Effect' advanced Sound Wave question

    When a car is approaching it has a higher frequency and shorter wavelength. When it has passed sound waves are a lower frequency due to a longer wavelength. Question: Does the higher frequency contain more energy when compared to the low frequency? IF IT DOES NOT, then could it possibly be...
  47. M

    How to find energy of sound wave

    Homework Statement In room temperature air, which of the following sound waves would have the greatest energy associated with it? A. A wave with lambda equal to 4.7 on B. A wave with a frequency of 2.6 Hz C. A wave which has a distance between adjacent nodes (1/2lambda) of 21mm...
  48. P

    Amplitude Of Single Tone Sound Wave = Loudness ?

    Amplitude Of Single Tone Sound Wave = "Loudness"? Hello, Given a single tone sound wave: x(t) = A * sin( 2 * pi * freq * t ), what does the 'A' actually represent? Peak Intensity? Intensity Level? Peak Amplitude Pressure? What is adding to my confusion is this link...
  49. D

    Sound wave in a tube of air with holes (lab)

    Homework Statement I had a Physics lab with the following setting: A signal generator is connected to a speaker which is located on one end of a tube. This creates the sound wave. The tube is open on both ends. A micro is movable along the tube and it is connected to an occsilator which...
  50. L

    Calculating Energy in Sound Wave

    Homework Statement How does the sound energy level produced by woodwind instruments (a piccolo, a clarinet, and a bassoon) compare to the sound energy level produced by string instruments (a violin, a cello, and a double bass) and brass instruments (a trumpet, a trombone, and a tuba)? I am...
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