# Questions tagged [harmonics]

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### Phase difference of standing waves

The phase difference of a standing wave is zero. The above statement is found online when searching about standing waves. However, it doesn't make much sense to me. Consider the above diagram of a ...
1 vote
30 views

### Harmonics in closed and open pipes

What exactly would happen if we sent a frequency that was not one of the harmonics into a closed and open pipe? What would happen if we gradually increased this frequency? From my understanding, I ...
40 views

### Phase difference problem

What's the phase difference between A and B on the following diagram. Where it is a standing wave. This question doesn't even make sense to me as from watching animations of standing waves, points A ...
120 views

### Clarifications on standing waves within a pipe?

Standing waves are causing great confusion for me. I have read many answers on stackexchange. However, I still don't understand standing waves within closed and open tubes. Problem 1. I struggle to ...
1 vote
50 views

### How is wavelength defined for standing waves?

How is wavelength defined for standing waves? I cannot understand why the first harmonic is half a wavelength rather than a full wavelength. I see how wavelength is defined for progressive waves but I ...
122 views

### Why do water sounds different at different levels?

I observed that when we fill a water bottle it sounds different at different levels of height. means it sounds different while filling at $\frac{1}4$ level and different at $\frac{1}2$. I just want to ...
452 views

### How to create a standing wave that doesn't oscillate with the fundamental frequency?

Is there a way to make the string on my violin vibrate in an overtone frequency instead of the fundamental frequency?
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### First Harmonic/Closed Tube/Net Transfer of Energy

Standing waves have no net transfer of energy. But, when watching simulations of the first harmonic for a closed tube, I see what looks like a transfer of energy - the particles clearly appear to ...
1 vote
80 views

### Can a pendulum have detectable harmonic frequencies

Can a pendulum produce harmonic frequencies? Like could I detect harmonic frequencies if I had a sensor on the pendulum?
1 vote
110 views

### Why is time harmonic follow the form of $e^{-i\omega t}$, not $e^{i\omega t}$? [closed]

In physics, when we solve an PDE or ODE, the solution usually has the form of \begin{equation} f=C_+e^{i\lambda x}+C_-e^{-i\lambda x} \end{equation} and the "causility" will eliminate one ...
46 views

### What is the relationship between the different frequency vs decibel graph peaks in the famous 'mass of coin question'?

In the popular answer for the coin-mass question of Physics Stack Exchange, So, I decided to try it out. I used Audacity to record ~5 seconds of sound that resulted when I dropped a penny, nickel, ...
432 views

### What do I hear when listening to a computer-generated sine wave?

When I use a sine-wave generator (such as this one), I give credit to the software and my hardware that a pure sine wave is produced (as close as is technologically possible) — that is, no harmonics. ...
64 views

### In what respect does the wave pattern of a noise and music differ?

Does the wave pattern of musical sounds contain only harmonics (other than the fundamental frequency) while noise contains random overtones (that are not harmonics)?
196 views

### The definition of "total curvature" for a scalar field

In Modern Electrodynamics, Zangwill remarks that the total curvature vanishes at every point where $\nabla^2 \varphi = 0$. Now my question(s): how is "total curvature" defined for a scalar ...
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### What is the simplest PDE/ODE/model I can use to understand how nonlinearities can lead to leakage of energy to higher harmonics in an oscillator?

I came across this problem in the study of surface waves in an oscillating cylindrical vessel of liquid. There are various eigenmodes described using Bessel functions, and energy transfer can happen ...
1 vote
79 views

### Is there a 'better' tuning frequency than 440 Hz? [closed]

My apologize if this question is a bit broad or open ended but I'm asking here rather than a music forum for two reasons: I'm trying to gain a better understanding of the physics of sound and ...
497 views

### What are harmonic waves?

I am studying waves for my examination. Harmonic waves is also in my syllabus and I don't know what it is. I searched for it on google and got two possibly different answers. One answer is from en....
63 views

### HOW are harmonics generated in longitudinal waves on the particle level?

I have been looking through the physics.se and all over the internet for weeks now honestly, and I still don't understand how harmonics are formatted on the particle level. Yes, I know that only ...
38 views

### The cause of higher harmonics amplitude drop in an air column?

In the case of the real life string, I believe I understand the cause of the amplitude drop as we go into higher harmonics: the bendability of the string is not infinite and as we get lower ...
15 views

### How does air make free ends in standing wave work in an open tube? [duplicate]

In open tubes, we can observe standing waves with free ends. It was interesting that air makes free ends, but I couldn't find how air makes free ends on the internet or in books. How does air make ...
1 vote
33 views

### Length of a water column executing SHM in a U-shaped Tube

I was watching the lecture 30 of Walter Lewin ( 8.01 ). Here is a link: https://youtu.be/hAYeA3Wwb4U At 29:30, when he was describing the SHM of water in a U shaped tube. Lewin says that for the ...
57 views

### Does rope in a standing wave expand and contract as it moves between being straight vs sine?

Images of standing waves often show two people using a jump rope. The shape of the rope goes from straight to waves to straight, then a sine wave the other way and then straight again as it repeats. ...
79 views

### Why only harmonics allowed in the Casimir effect?

My question is really a request for an intuitive explanation as to why only harmonic frequencies of photons allowed between two conduction plates. Why do the plates have to be conductive? And can real ...
175 views

### Is timbre a physical noumenon or a perceptual phenomenon? [closed]

I have a question relating the "timbre" of a sound, namely what is exactly and exhaustively defined by this word? Most definitions that I come across seem somewhat loose as "the color ...
232 views

### How can I calculate the number of nodes on a plucked string?

Given the length of the guitar string, can you predict the number of nodes that would exist on that string? My textbook says that there are an infinite number of harmonics that can be created when a ...
1 vote
102 views

### How does one apply the phase change of $π$ on reflection at the rigid end of a string?

Consider a string, with a free end $P$ and another end $Q$ which is rigidly fixed. Now, we start oscillating the point $P$ (with $0$ initial phase difference) and a wave starts traveling(in the ... 127 views

### Does the standing wave equation proof require $\ell=Nλ$? [closed]

Consider two identical sources $S_1$ and $S_2$ of waves, separated by a distance $\ell$ (as shown in the figure). The sources produce waves in opposite directions(and towards each other). Now, ... 632 views

### Why does an antinode form at the open end of an organ pipe?

I recently learnt about reflection of waves in various media and the resultant standing waves formed. In a string which is tied at an end, the wave formed reflects with a phase difference of 180 (at ... 42 views

### How to calculate the overall harmonics of a system of tubes?

Let's say there is a tube closed at one and and open from the other. The open end is connected to another tube (of smaller diameter) which is open from both ends. How can I calculate the overall ...
166 views

### What exactly happens, step by step, in string harmonics?

I know that a string when plucked shows harmonics but I do not really understand how. Like, I understand resonating air column and how standing waves are formed there, but I can't seem to get the step ...
432 views

### Why does plucking a string produce harmonics instead of a pulse?

If I jerk a wire from the free end fixed at an end and then fix the free end, it will produce a pulse travelling back and forth between the two ends. So in a string fixed at both ends, if we pluck it ...
60 views

### Why is the Ocean Blue? [closed]

I'm writing an article on the physical property that binds Music and Water -- Harmonics. I understand that the blueness of ocean water is due to the three vibrational modes of water (i.e, symmetric, ...
1 vote
170 views

### Standing wave in a string clamped at one end

*In the case of a standing wave formed with one end clamped (fixed), there is an anti-node at the free end irrespective of the overtone. My question is why is there has to be an antinode. Is there any ...
85 views

### Steven Weinberg says $L$ is the fundamental EM wavelength in a cubical cavity $L^3;$ not the typically asserted $2L.$

This is from Steven Weinberg's Lectures on Quantum Mechanics, 2nd Ed., page 2: For instance, for a cubical box of width $L,$ whatever boundary condition is satisfied on one face of the box must be ...
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### Standing waves confusion

Its just so confusing as to why the antinodes are formed from the constructive interference by superposition of the wave formed by the incident wave and the reflected wave... The phase difference is ...
49 views

### Which harmonic we hear from organic pipe from all possible outcome?

I have gone through about each case of standing wave in open and closed organ pipe and understand antinode and node concepts. But i am confused that if all harmonics are possible in organ pipe, then ...
1 vote
196 views

### Plucked string eigenvalues/harmonic frequencies: integer multiples (or not)

I'm trying to derive a model of a plucked string from Newton's second law. My derivation results in $$ω_n = C\cdot\sqrt{n},\, n=1,2,3\dots\text{integer}$$ I think it should be ω_n = C\cdot n,\, n=1,...
1 vote
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### Why are there both antinodes at both ends of the tube? [duplicate]

I learned stationary/standing waves the other day. For stationary waves in open tubes, the textbook says both ends must have an antinode. Can anyone tell me why? (shown as figure) And also, when ...
239 views

### Upper limit of Schumann resonance harmonics?

This is a re-post from the Earth Science Stack Exchange which was posted two month ago. Due to the nature of the question and the SE site, it might be better to post this question here. As the Earth'...
115 views

### How do standing waves produce a note?

I just learned standing waves in class. And I know that fundamental frequency is the minimum frequency with which a standing can exist on a string. Then we talked about the role of standing wave in ...
1 vote
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For a string fixed at both ends, with a fundamental frequency of 440Hz, can there be a harmonic when a wave of frequency 220Hz is sent across the string? my book says no, but I disagree; can't ...
111 views

### How to draw relation between Time Period and Amplitude of SHM?

Can we draw a relation between Time period and amplitude an object doing SHM? I came up with something but I’m not sure if it’s correct. $TA = k$, where k is a constant I came up with this just by ...
1 vote
30 views

### Find the frequency of the first two harmonics of a vibrating string

I have a string of length $2 \;\text{m}$ and the wave velocity is $120 \;\text{m/s}$, find the frequency of the first two harmonics. My attempt, what I must do is to solve the wave equation on the ... 152 views

### What kind of frequency effects does a guitar body have on sound?

These are the questions I read through before asking this: Guitar string - feedback from the body Sound due to guitar Waves on a guitar string https://music.stackexchange.com/questions/5489/why-do-...
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### Identifying speech sounds from sound waves [duplicate]

TLDR: How do we differentiate, say, a "A" from a "O", how do we identify speech sounds? If formants are the key, how is it possible to identify it regardless of the pitch (...
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### Harmonic wave (infinite length and duration)

I am not sure why a harmonic wave is said to have infinite length and duration. I found this image, but I am not sure I have really understood it. Here, there are three waves: the first one is a ... 28 views

### Saturn's moons - getting a stable harmonic model for Mimas and Encyladus

I have built a HTML/Javascript solar system model. It is working well with real time animation. https://abetz-rouse.com.au/planetarium I don't want to get into the deficiencies of my choice of ...
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### Why can harmonics be a different note than their fundamental frequency?

I was under the impression for the longest time that when you hear a harmonic on a string, its basically a sum of different resonating frequencies, which are all INTEGER multiples of the base ...