What is Standing waves: Definition and 259 Discussions

In physics, a standing wave, also known as a stationary wave, is a wave which oscillates in time but whose peak amplitude profile does not move in space. The peak amplitude of the wave oscillations at any point in space is constant with time, and the oscillations at different points throughout the wave are in phase. The locations at which the absolute value of the amplitude is minimum are called nodes, and the locations where the absolute value of the amplitude is maximum are called antinodes.
Standing waves were first noticed by Michael Faraday in 1831. Faraday observed standing waves on the surface of a liquid in a vibrating container. Franz Melde coined the term "standing wave" (German: stehende Welle or Stehwelle) around 1860 and demonstrated the phenomenon in his classic experiment with vibrating strings.This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions. The most common cause of standing waves is the phenomenon of resonance, in which standing waves occur inside a resonator due to interference between waves reflected back and forth at the resonator's resonant frequency.
For waves of equal amplitude traveling in opposing directions, there is on average no net propagation of energy.

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  1. H

    I Standing Waves w/ 2 Free Ends: Exploring the Mystery

    Hi everyone! As we all know standing wave of 2 fixed ends formed by the combination of coming wave and reflection wave. But I wonder why there still have a reflection wave combinating with coming wave to form standing wave of 2 free ends? Many thanks.
  2. J

    A Reducing standing waves with phase randomization

    Will constantly randomizing the phase of an audio signal, say a speaker in the corner of a square room, reduce standing waves (i.e. room modes) in the room? For example if you wanted to create a diffuse field in a small (i.e. no standing wave interference patterns) at low frequencies.
  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. hiver

    Finding the value of g using 2nd Harmonic Frequency

    Homework Statement As the captain of the scientific team sent to Planet Physics, one of your tasks is to measure g. You have a long, thin wire labeled 1.80 g/m and a 1.30 kg weight. You have your accurate space cadet chronometer but, unfortunately, you seem to have forgotten a meter stick...
  5. V

    Find the Minimum Length of a Vibrating String

    Homework Statement the equation of a stationary wave produced on a string whose both ends are fixed is given by y= [0.6sin(pi/10)x]cos(600pi)t what could be the smallest length of string?Homework Equations k=2pi/wavelength The Attempt at a Solution i got the wavelength to be 20 but don't know...
  6. H

    How do standing waves produce sound?

    Hi i've been taught that standing waves do not transfer a net energy. but standing waves are formed in instruments, and we can hear them - so some sound energy/kinetic must be transferred to surrounding particles to reach our ears? how does this work? please could you help me if my understanding...
  7. H

    How Does a Bugler Control Frequency with Lip and Air Pressure Adjustments?

    Homework Statement By adjustin her lips correctly and blowing with the proper pressure, a bugler can cause her instrument to produce a sequence of tones, amog which are the following: 440, 660, 880, 1100, . . . Hz --- all without changing the length of the air column. (b) What is the ffective...
  8. F

    Reflection of Waves and Formation of Standing Waves

    I have three doubts in regard to waves on a string which I will try to make as clear as possible. For this purpose, I have considered a general wave: $$y_i=y_0\sin(\omega t - kx)$$ (1) If a wave pulse: $$y = y_0 e^{\frac{-1}{T^2} \left(t-\frac xv \right)^2}$$ is incident against a rigid...
  9. N

    No mass for mass per unit length

    Homework Statement A ski gondola is connected to the top of a hill by a steel cable of length L and radius R . As the gondola comes to the end of its run, it bumps into the terminal and sends a wave pulse along the cable. It is observed that it took T seconds for the pulse to return. What is...
  10. Mnemonic

    Goniometers and Standing Waves

    Homework Statement Initially your receiver is positioned at a distance of 8.4 cm from the goniometer and recording a maximum intensity. You move it through 10 minimums in the intensity and then stop at the next maximum intensity. The receiver is now a distance of 27.3 cm from the goniometer...
  11. Toon

    Superposition: Adding two waves together -- amplitude help

    Homework Statement " Two traveling waves are generated on the same taut string. Individually, the two traveling waves can be described by the following two equations: If both of the above traveling waves exist on the string at the same time, what is the maximum positive displacement that a...
  12. K

    Sound standing waves paradox....

    If you seal a loudspeaker at the end of a tube and close the other end of the tube you will get standing waves; but what are the boundary conditions at the speaker for the sound pressure wave? Pressure =0 or Pressure = MAX? I find no mention of this in the literature. To find out I performed a...
  13. Raman Choudhary

    Understanding Normal Modes and Standing Waves in Vibrating Systems

    We know that in normal mode all the particles of the system vibrate with same frequency but if take a string fixed at both ends and make it vibrate in one of the normal modes in some cases we see nodes being formed at certain points and we say these are the points with zero amplitude but since...
  14. kelvin490

    Question about intensity of EM waves

    For electromagnetic wave if it's reflected from a perfect conductor standing wave can be form. I wonder why Poynting vector can be used to describe the intensity of standing EM wave. (see p.19 of http://web.mit.edu/viz/EM/visualizations/coursenotes/modules/guide13.pdf ). From some textbooks...
  15. D

    Classifying standing waves and their frequencies

    Homework Statement 40-cm long string, with one end clamped and the other free to move transversely, is vibrating in its fundamental standing wave mode. If the wave speed is 320 cm/s, the frequency is[/B] A 16 Hz B 8 Hz C 32 Hz D 2 Hz E 4 Hz Homework...
  16. D

    Standing waves on a moving string

    Hello, I have the configuration as shown in attached picture. I know how to calculate string tension and measure frequency if the string is not moving. But what happens if the string is moving at a constant speed? Are there still standing waves? Can we still calculate the string tension? What if...
  17. M

    How can standing waves be created on a string fixed at both?

    Hello. So I am having some trouble answering this question and I would really appreciate some help. I figure I should probably first define what standing waves are and I know that they are the result of the repeated interference of two waves of identical frequency while moving in opposite...
  18. H

    MATLAB Series of Standing Waves in Matlab

    %PLOTTING TIME DEPENDENT MOTION OF A STANDING WAVE %Define Parameters a_n = 1; k = 5; w_n = 5; x = 0:0.05:4; t = 1:0.05:20; for j=1:length(t) for i=1:length(x) u(i) = a_n*sin(k.* x(i)).* cos(w_n.*t(j)); %Formula for displacement end pause (0.1) plot(u)...
  19. A

    Standing waves in tube closed tube

    Homework Statement A tone with frequency 2,00 * 10^3 Hz is held above a tube filled with water. The water level is increased and decreased. When the water level is 5.7cm below the opening of the tube, the first sound maxima is heard. When the water level is 39.3cm below the opening of the...
  20. O

    Produce Standing Wave Problem

    Homework Statement The equation of a transverse wave traveling in a string is given by y(x,t) = 10 cos (π/2)(0.0050x - 8.0t + 0.57), in which x and y are expressed in centimeters and t in seconds. Write down the equation of a wave which, when added to the given one, would produce standing...
  21. O

    Amplitude and Velocity of Component Waves

    Homework Statement A string vibrates according to the equation y(x,t) = 2.0*sin (0.16x)cos (750t) , where x and y are in centimeters and t is in seconds. (a) What are the amplitude and velocity of the component waves whose superposition give rise to this vibration? (b) What is the distance...
  22. sushichan

    How does tension affect the frequency of a standing wave on a string?

    Homework Statement A string is held under tension, with both ends fixed, and has a fundamental frequency of 250 Hz. If the tension is doubled, what will the new frequency of the fundamental mode be? Homework Equations The Attempt at a Solution I don't know how tension can affect the equation...
  23. S

    Length of a Steel Wire (Standing Waves)

    Question: A copper wire and steel wire with identical diameters are placed under identical tensions. The frequency of the third resonant mode for the copper wire is found to be the same as the frequency of the fourth resonant mode for the steel wire. If the length of the copper wire is 3.44 m...
  24. Kevin Spacey

    Describing how to make a standing wave?

    I'm struggling in physics class, and I really need help with this question. "If you are holding a spring in your hand and making waves, describe how to make a standing wave at the 2nd resonance frequency (next frequency over the fundamental). Include a sketch with your answer." What does this...
  25. H

    Square wave and sine wave -- How standing waves are formed?

    Why do the sound waves reflect and form standing wave when they travel along a string with sinusoidal waveform? But they do not reflect back when they are in square waveform ?
  26. S

    Standing Waves Under Boundary Conditions

    Homework Statement See the figure below. A thin pipe, open at both ends, with length 0.400 m and 1.0 cm diameter is placed vertically in a cylindrical bucket so that it nearly touches the flat bottom of the bucket, which has an area of 0.100 m2 . The air temperature is 22o C. Water is slowly...
  27. C

    Standing waves corresponding to a confined particle

    I'm just beginning to learn about quantum mechanics. My background in physics is very limited (Physics 1,2,3 and thermo). Here are my questions: A wave packet (which represents a particle) can be formed from the superposition of waves over a range of continuous wavelengths (i.e. an integral of a...
  28. Physics_Lovvee

    Can Standing Waves Have Both Transverse and Longitudinal Components?

    Can standing waves be both transverse and longitudinal?
  29. gracy

    What is the difference between standing waves and reflection in waves?

    I don't know from where this type of image corresponds to standing waves? http://www.stmary.ws/high school/physics/home/notes/waves/img7A.gif As at any point of time either original wave would be present or it's reflection as when the original wave would reach and hit wall then only it would...
  30. R

    What is a closed pipe ( standing waves)

    Homework Statement does it mean only one side of the pipe is open or both sides are closed. Homework EquationsThe Attempt at a Solution i think it means only one side is open, but i just need to make sure
  31. H

    Confusion regarding Standing Waves and Reflection resulting in Phase Change

    So a standing wave is one which looks to be standing still at certain harmonic frequencies. At these frequencies, when the wave reflects off the end, it will undergo a phase change of 180 degrees. This creates constructive interference as shown below: In the case of a wave on a string, since...
  32. K

    What is the velocity of standing waves in a pipe based on resonance distances?

    Homework Statement A tube is filled with air at 770C, one end open and on the other a piston. in the open end a tuning fork oscillates with 500[Hz]. The piston is set to different positions and at the distances of 18, 55.5 and 93 cm from the open end there is resonance. find the velocity of the...
  33. K

    What is the correct frequency for a 20 cm pipe with open and closed ends?

    Homework Statement What is the base frequency of a 20 cm pipe which is open on both ends. Again but closed on one end. Homework Equations u=velocity, \lambda=wave length: \lambda=\frac{u}{f} Velocity in air=348[m/sec] The Attempt at a Solution I understand these are standing waves in air. In...
  34. K

    Longitudinal standing waves in gas

    Homework Statement In the uppermost drawing is a propagating wave. the distance between two successive high pressure areas, as seen in the picture, is the wavelength \lambda, but in the drawing just underneath it, the Kunt pipe, the distance between two successive heaps of cork is \lambda/2...
  35. A

    Understanding Amplitude and Waveforms

    Homework Statement http://puu.sh/bZQiV/43f7515806.png Homework Equations This is a conceptual conception so no equations[/B]The Attempt at a Solution I believe answer is D since it is the longest and thus can have the highest amplitude. Is it correct?[/B]
  36. B

    Why are standing waves on a guitar string sinusoidal?

    Ok I understand the idea that a standing wave can be represented as the sum of two traveling waves going in opposite directions with same stuff but what I don't understand is why the waves on a guitar string are sinusoidal. I mean I know looking at them, they look sinusoidal but could they be...
  37. A

    Archived Standing Waves Proof for Open-Open Tubes

    My teacher assigned me to prove open-closed and closed-closed standing waves patterns using math. With closed-closed, it was fairly easy: $$\begin{align} D(x=0,t)&=0\\ D(x=L,t)&=0=2A\sin(kx) \end{align}$$ Isolate $$L$$ to find that $$\lambda=2L/m$$. Similarly for closed-open. $$\begin{align}...
  38. A

    Are atomic orbitals electron standing waves?

    Do electrons really exist as standing waves in an atom? If so, are these standing waves what are known as atomic orbitals?
  39. J

    Understanding Standing Waves and their Velocity on a String

    Is a standing wave actually a traveling wave appearing to be still do to interference of two different waves? If the above statement is true, how can a resultant wave even form? The wave traveling forward is not in or at the same time as the wave reflecting back. (How can there interference...
  40. P

    Can I prevent setting up standing waves in my COMSOL model?

    Can I prevent setting up standing waves in my COMSOL model? I'm using integration over two opposing faces to get the pressure at the 'outlet' - but it seems that no matter what I do to prevent the standing waves, they won't go away. Any help would be great, Thanks
  41. A

    How can we create standing waves on a string with only one fixed end?

    Whenever we prove standing waves in books, they define two waves: D1(x,t)=asin(kx-wt) D2(x,t)=asin(kx+wt) Why don't we ever put phase constants? What if the phase constants for each is different? Will there be a standing wave?
  42. Just_some_guy

    Standing Waves Question: Find Wavelength and Amplitude in Two Connected Strings

    This is my first post on the forum, and I hope you guys can help me My questions is this, There are two strings which are connected with constant tension everywhere, but they have different linear mass densities. The second mass density is double that of the first (μ1= 2μ1). A wave propagates...
  43. N

    Solving Standing Waves Problem: Why Nodes at Multiples of 3 Remain Unexcited

    I'm unclear about the entire idea of why if a string fixed at 2 ends is plucked at a point, say L/3 from the left, the node at the pluck point and any node that is a multiple integer of 3 would be unexcited. Trying to see it mathematically, and I've only been able to arrive at is this...
  44. B

    Exploring Fundamental Vibrations: Plotting Tensions and Lengths on a String

    Homework Statement This is a prelab question which I hope for some confirmation I'm thinking right. A vibrating string is vibrating in the fundamental mode. The question is to plot a graph with a succession of applied tensions T on the x-axis and the resultant length L of the fundamental...
  45. G

    Wavelengths of standing waves on a string

    Homework Statement Consider a string of length L held fixed at both ends. The string can be shaken up and down and, at certain frequencies, the result will be a standing wave pattern on the string. Find the five longest wavelengths (call them λ1, λ2, λ3, λ4, and λ5) of the standing wave...
  46. B

    Confused about string instruments and standing waves

    So I made a banjo for my project and now I need to do the calculations. Well since its a string instrument I have to find the frequencies of the first four harmonics, I already have the fundamental frequency. Is it fine to use: fn = nf1 Not sure because I thought that was for open end air...
  47. A

    Acoustic standing waves with an open far end

    My textbook says I'm confused by this, because isn't a standing wave caused by reflection of the waves once it has hit the end of the tube and reflects backwards. How can sound waves be reflected from the open air? Thank you for taking the time to answer. :)
  48. B

    Standing waves on a fixed string

    Hello, Homework Statement Two wires, each of length 1.8 m, are stretched between two fixed supports. On wire A there is a second-harmonic standing wave whose frequency is 645 Hz. However, the same frequency of 645 Hz is the third harmonic on wire B. Find the speed at which the individual...
  49. P

    How exactly are standing waves formed?

    I understand the equations for the nth harmonic and so on, but I really don't get how a standing wave is formed. My physics teacher said that an incident wave and an identical reflected wave interfering would cause a stationary wave, but I still don't understand how this happens. For example...
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