Sound waves Definition and 333 Threads

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. M

    What factors affect the pitch and tuning of organ pipes?

    The topic came up the other day in class, about how the wave frequencies vary in each pipe of an organ. I am looking for some comprehensive information on the topic, and it would be great if someone could direct me, or maybe help a little bit as I am not so sure, as we haven't covered the topic...
  2. daniel_i_l

    Why Does Filling a Glass Affect Its Sound Wave Pitch?

    If you fill a glass with water and hit it on the side with a knife then you get a higher pitch the more you fill it up. Why is this? When you hit the glass you aren't really making the air in the glass vibrate as you do when you blow over the top of a bottle, you're just making the glass...
  3. N

    Why do scientists use sound waves in water?

    Why do scientists use sound waves on water? And also can you provide some examples of applications of sound waves on water, for ex. submarines.
  4. M

    Question regarding sound waves in musical instruments

    My question is regarding musical instruments. Their are waves produced in wind instruments and in stringed instruments. If a wind instrument (lets say a tuba) is played directly next to a stringed instrument (lets say a guitar) will the sounds waves (in air) produced by the wind instrument...
  5. S

    Comparison of sound waves in air and underwater

    [SOLVED] Comparison of sound waves in air and underwater Homework Statement In air, the human ear is most sensitive to sound waves of 3300Hz. The auditory canal is part of the human ear. It is a tube of length 0.025m, i.e. 1/4 the wavelength of sound with frequency 3300Hz. When under...
  6. S

    Calculating Relative Maximum for Sound Waves from Speakers Separated by .7m

    Homework Statement A pair of speakers separatd by .700m are driven by the same oscillator at a frequency of 690Hz. An observer originally positioned at one of the speakers begins to walk along a line perpindicular to the line joining the speakers. How far mus the observer walk before...
  7. P

    How is Pressure Calculated in a Moving Fluid for Sound Waves?

    i saw the 'proof' of the wave equation for a sound wave in a medium assuming the wave equation for a dissplacement wave. that is the equtaion s=s_{0} \sin(kx-wt) is supposed to hold for all points for a wave propagating in the x direction. then using this he found out the excess pressure at...
  8. J

    How Close Can You Be to Speaker B for Destructive Interference?

    [SOLVED] Interference of Sound Waves Two loudspeakers, A and B, are driven by the same amplifier and emit sinusoidal waves in phase. The frequency of the waves emitted by each speaker is 172 Hz. You are 8.00 m from speaker A. Take the speed of sound in air to be 344 m/s. What is the closest...
  9. J

    How Close to Speaker B Causes Destructive Interference at 172 Hz?

    [SOLVED] Interference of Sound Waves Two loudspeakers, A and B, are driven by the same amplifier and emit sinusoidal waves in phase. The frequency of the waves emitted by each speaker is 172 Hz. You are 8.00 m from speaker A. Take the speed of sound in air to be 344 m/s. What is the closest you...
  10. J

    What is the speed of sound in air using the Young's Double Slit Experiment?

    Two loudspeakers are placed side by side a distance d apart. A listener observes constructive interference while standing in front of the loudspeakers, equidistant from both of them. The distance from the listener to the point half-way between the speakers is l. One of the loudspeakers is...
  11. K

    How Are Standing Sound Waves Solved?

    Solved it. Thanks anyway.
  12. S

    Sound waves move from air to water

    I want you to help me in resolving these questions First question When Down stone in the basin of water eroded the bandwidth with dimension The Center fell in stone. What explanation The second question Sound waves move from air to water. Discussed the impact on The frequency and...
  13. P

    Sound waves in a 1-molecule thick liquid

    Imagine a 1-molecule thick layer of liquid, evenly dispersed across a perfectly flat surface. This surface is (for this thought experiment) impenetrable and sound does not pass through it; it is unable to resonate or vibrate. If we apply sound waves or some other frequency/wave generation to...
  14. daniel_i_l

    The Longer Reach of High Frequency Sound Waves

    Why can a sound wave with a high frequency travel further and stay more concentrated (i guess there are basically the same) than one with a lower frequency? Thanks.
  15. D

    Exploring Standing Sound Waves: Small Scale Patterns at Antinodes

    Homework Statement I just used the Kundt's tube to illustrate the effect of a standing sound wave in a glas tube. The characteristic nodes and antinodes were perfectly visible and some small scale striated vibration patterns at the antinodes were prominent. What is the physical explanation for...
  16. P

    Solving Wavelength & Tone of Sound Waves

    (a) First, consider a string of length 1m attached at both ends. It sounding a fundamental tone of 440 Hz. What is the wavelength of the above waves on the string? What is the speed of the waves on the string? (b) Now consider a Boomwhacker™ tube open at both ends, sounding a tone of 440...
  17. E

    Amplitude of Sound Waves from Two Sources at a Point

    [SOLVED] Amplitude of Sound Waves from Two Sources at a Point Problem. Two sources, A and B, emit sound waves, in phase, each of wavelength \lambda and amplitude D_M. Consider a point P that is a distance r_A from A and r_B from B. Show that if r_A and r_B are nearly equal (r_A - r_B \ll r_A)...
  18. L

    Why will ultrasonic waves not interfere with other sound waves in water?

    why will ultrasonic waves not interfere with other sound waves in water?
  19. M

    Constant Properties of Sound Waves

    I was wondering what property in sound stays the same when the sound wave's speed, pitch, and/or tempo are changed. I would like to know this to create a time coded signal on vinyl record for a vinyl emulation software.
  20. B

    Exploring Sound Wave Interactions and the Mystery of Quieter Freeway Noise

    Does sound waves interact with each other and cancel each other out. I'm not talking about constructive or deconstructive interference either. If a strong sound source is pointed towards a weak one does the compression of air interact with other waves. I don't know if I asked it right or if...
  21. C

    How Do Sound Waves Travel Through Different Media?

    Homework Statement An explosion occurs at the end of a pier. The sound reaches the other end of the pier by traveling through three media: air, fresh water, and a slender metal handrail. The speeds of sound in air, water, and the handrail are 343, 1482, and 5040 m/s, respectively. The sound...
  22. T

    How does electricity create sound waves?

    you know the high pitched buzzing you can sometimes hear from electric wires, or from the capacitor on a camera charging (for the flash)? i was wondering what creates that noise. my best guess is that it is caused by the vibrations from the electrons bumping into each other, but it seems like...
  23. E

    Measuring Sound Waves: How It Began & How To Do It

    Who was the first person to measure sound waves and how did he do it. Also how can you measure sound waves with a tuning fork.
  24. V

    American Windfarms Discussion: Sound Wave Power Generation

    Our discussion group, American Windfarms was contacted by students in NJ, who are working on and internet technology challenge...to learn whether they can convert sound wave generation into power generation. Any ideas??
  25. A

    Light and Sound Waves: Can You See Through Walls?

    A strange question that I recently thought of. Both sound and light are waves so why is it that I can hear through walls and around corners but can't "see" through walls and around corners?
  26. K

    Jet airplane (sound waves) problem

    The intensity of the sound wave from a jet airplane is 9.00 W/m2 at a distance of 4.8 m. At what rate does the jet airplane radiate energy in the form of sound waves? Assume that the sound wave radiates from the airplane equally in all directions. I am having trouble starting this problem...
  27. A

    Solve Homework: Sound Waves Lengths in Tube w/ 85cm Guitar String

    Homework Statement A guitar string that is 85cm long is plucked. The fundamental frequency of the string is 350Hz. The string's tension is then increased and its wave speed is 1000m/s The string is vibrating at its fundamental frequency and a closed tube is next to it. A loud sound is produced...
  28. S

    Calculating Distance from Earthquake Using P and S Waves

    When an earthquake occurs, two types of sound waves are generated and travel through the earth. The primary, or P, wave has a speed of about 8.0 km/s and the secondary, or S, wave has a speed of about 4.5 km/s. A seismograph, located some distance away, records the arrival of the P wave and...
  29. kreil

    Solving Sound Waves Problem: Direction of Sound Origination

    The problem is this: Only two recording channels are needed to create the illusion of sound coming from any point located between two speakers of a stereophonic sound system. If the same signal is recorded in both channels, a listener will hear it coming from a single direction halfway...
  30. kreil

    Intensity of periodic sound waves

    The problem is this: A firework charge is detonated many meters above the ground. At a distance of 400m from the explosion, the acoustic pressure reaches a maximum of 10.0 N/m2. Assume that the speed of sound is constant at 343 m/s throughout the atmosphere over the region considered, that...
  31. J

    Weightlessness and sound waves

    What are the effects of weightlessness on sound waves, if any? [Not talking about human hearing or ability to locate sound]
  32. M

    How Do You Combine Two Sound Waves Mathematically?

    Hi, I need to determine the sum of the two sound waves and express it in the form y=Csin(kx-wt-"theta") where w is omega. The two waves are y=Asin(kx-wt) where w is omega y=Bsin(kx-wt-"phi") where w is omega I used a trigometric formula and got it to the point where it equals...
  33. J

    Sound waves distorted in certain speaker enclosures?

    my theory may be sloppy and wrong - but here it goes when people start talking about speakers and their enclosures there are generally two types used, ported and sealed. sealed being just that, and airtight box with a speaker in it. but a ported box is far from air tight instead they put a...
  34. P

    Sound Intensity and Sound Waves

    I am having trouble with these two problems.. 1.By how many decibels do you reduce the sound intensity level due to a source of sound if you quadruple your distance from it? Assume that the waves expand spherically. For this one do I have to find ratios of I1/I2 and then substitute it in...
  35. D

    How to Use Fourier Transforms to Manipulate Sound Waves?

    It's a tech.,and it is said that that had been done by MIT,then anybody know the details?
  36. F

    Solving Sound Waves Problem: X vs Y

    I am clueless on how to approach the following problem, and was wondering if anyone would be able to help me. Thanks!
  37. B

    Calculating Frequency and Wavelength of Sound Waves in Water and Air

    i really had troubles with solving this problem and it would be greatly appreciated if i can get a full solution, thank you A vibrating 400.0 Hz tuning fork is placed in fresh water. What is the frequency in hertz and the wavelength in metres. a) within the water at 25 C b) when the...
  38. T

    Sound waves and eardrum problem

    A 50 dB sound wave strikes an eardrum whose area is 4.1 * 10-5 m2. (a) How much energy is absorbed by the eardrum per second? W (b) At this rate, how long would it take your eardrum to receive a total energy of 1.0 J? years I have tried to solve using I=2pi^2f^2A^2pv and got f=280 ...
  39. K

    How Do You Calculate Sound Speed with Changing Path Length Interference?

    Sound Waves Problem and I'm Stuck! Please Help! Linear Superposition The sound produced by a loudspeaker has a frequency of 12,000 Hz and arrives at the microphone via two different paths. The sound travels through the left tube LXM, which has a fixed length. Simultaneously, the sound...
  40. A

    SImple question about sound waves but need a good reason

    Sound waves and frequency In my opinion, the answer is that frequency affects directly to the velocity of the sound. Therefore, high frequency sound have high velocity. Can someone post if this is right or not? If not, can anyone provide the correct answer? Thanks in advance.
  41. C

    Two Homework Questions on Sound Waves

    I have a couple homework questions that I am having trouble with...any help would be appreciated ASAP! 1.)A tuning fork generates sound waves with a frequency of 238 Hz. The waves travel in opposite directions along a hallway, are reflected by walls, and return. The hallway is 45.0 m in...
  42. C

    HELP PLEASE Spherical Sound Waves Problem

    A jackhammer, operated continuously at a construction site, behaves as a point source of spherical sound waves. A construction supervisor stands 63.5 m due north of this sound source and begins to walk due west. How far does she have to walk in order for the amplitude of the wave function to...
  43. N

    Solve Physics Exam Confusion: Sound Waves & Calorimetry

    My physics professor attempted to teach two chapters of new material within two class periods, but unfortunately this is not enough time to cover the material as in depth as we will be tested on. Exam is this mon and I am very confused about the things he did not explain - I feel like he left...
  44. A

    Sound Waves - phase difference from time delay

    For some reason I have trouble with questions like this. How would I get the phase difference if I were given the time delay of two loudspeakers side by side? I'll use this question as an example: "The speakers are now placed side by side. If the wire to speaker 1 is passed through a...
  45. F

    How Does Doppler Effect Influence Perceived Sound Frequency?

    7. A block with a speaker bolted to it is connected to a spring having spring constant k = 20.0 N/m as in Figure 3. The total mass of the block and speaker is 5.00 kg, and the amplitude of this unit’s motion is 0.500 m. If the speaker emits sound waves of frequency 440 Hz, determine the range in...
  46. S

    Sound Waves of Piston: Calculation & Amplitude

    I posted this in general physics forum but in retrospect I think I should have posted it here. Since piston compresses and decompresses a gas, it must be generating sound waves. Lets take a small engine with piston stroke 86mm, RPM 8000. An 8000 RPM means it is making 133.333 revolutions...
  47. S

    Can Sound Waves Travel at the Speed of Light?

    I am wondering what density is required for a sound wave to travel at the speed of light (if possible at all!) I'm not sure if there is a critical density at which a sound wave can go no faster. Another related question is about 'cerenkov radiation': is it the same thing as light? That is...
  48. I

    Question involving beats and sound waves

    Hi, I have a question involving beats and sound waves. When two sound waves (one with a MUCH LARGER Frequency than the other) combine, what would happen? Would there still be a beat pattern? Me, I think that if there still is a beat pattern, it would have the same frequency as that of the...
  49. Y

    How Can I Calculate Sound Waves in Air?

    Hello I am interested in calculating the sound waves created by objects in air. What is the resolution of details that needs to be dealt with in orer to calculate this? Can it be calculated by using traits of the object such as mass density, geometry and other related attributes? Or do you...
  50. B

    Longitudal waves - sound waves

    Hi. I am looking for correct mathematical definition of longitudal wave I am 3-D if somebody will help me with some link or explanation it will be great. Another thing: when I have a point source of waves i see that wavenumber changes from one point to point, is it wright? thanx
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