# Standing waves Definition and 42 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. ### Standing wave, phase and antiphase

I think I understand that points P and R are pi radians out of phase - reaching their max/min at the same time. But are P and Q in anti phase? What is antiphase exactly - is it when they are 180deg out of phase - or is it when they are anything other than totally in phase? I seem to find...
2. ### Effect of temperature on vibrational frequency of a violin string

Variables: Dependent: Vibrational frequency of violin string (Measured using mobile tuning app) Independent: Temperature in which string is plucked (Measured using infrared thermometer) Controlled: Violin String, Tension of violin string, Length of violin string, Method of plucking...
3. ### Displacement nodes for overtones

(4 / 3) * (1.8) = 2.4 = lambda 1st overtone: 2.4 / 4 = .6; (2.4 * 3) / 4 = 1.8
4. ### Standing waves between two speakers in phase

The solution provided in the manual poses that the point halfway between the nodes at each speaker is an antinode of pressure (node of displacement) but isn't that a contradiction to the fact that the speakers are in phase? My first thought was that they must interfere constructively and have...
5. ### I How does a standing wave form?

I understand how waves undergo superposition. However, for a standing wave, the reflected wave is a mirror opposite of the incoming wave. By the superposition principle, won’t the 2 waves add up to 0, at all points?

31. ### 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...
32. ### 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...
33. ### 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...
34. ### 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...
35. ### 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...
36. ### 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...
37. ### 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...
38. ### 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...
39. ### 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...
40. ### Standing (Stationary waves)

Can standing waves be both transverse and longitudinal?
41. ### Driver rod

Homework Statement http://puu.sh/bZQiV/43f7515806.png [Broken] 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]
42. ### 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...