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Wave vs waves

  1. Jul 20, 2011 #1
    Does a disturbance (that is continuous) propagating away from a point constitute just one single wave? Or does it constitute more than one wave?
  2. jcsd
  3. Jul 20, 2011 #2
    I don't have an answer. But if a rock drop in a still pond, it generate a ring of disturbance and propagate out like a ring. Behind the ring, it is all still again. I would not consider it is continuous and is one single wave propagating outwards.

    But if you have a continuous disturbance at the origin like you described, even the wave propagate out, it is ONE continuous wave.

    That's how I see it.
  4. Jul 20, 2011 #3

    Philip Wood

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    Gold Member

    Funnily enough, exactly this question came up in discussion with colleagues the other day. Generally, we favoured 'wave', even for a continuous sinusoidal disturbance, but we didn't think there was much wrong with 'waves', either!

    What I don't think is good is to divide a sinusoidal wave profile into portions each a wavelength long, and reserve the term 'wave' for each portion. But then nobody was suggesting doing so!
  5. Jul 20, 2011 #4
    what if you take a long rope and give a good whip as you finish your motion right on the ground? Guess what...you are going to see a single wave...this is called a "traveling wave" and it happens in the real world in many places...I, for one, found them during college studies in power transmission lines.

    On the other hand, I am not about the semantics...it seems as if a wave is wave whether it is a single distortion or multiples one in sequence...the word 'waves' seems to be applicable when you actually have waves of different source or frequency, etc, you know what I mean.
  6. Jul 20, 2011 #5
    Usually it is both....Generally, waves can be decomposed into constitutent components...sums, products,etc....

    An easy way to think about it is any trigonometric identity function:

    for example:

    Sin (x +y) = Sin(x)Cos(y) + Cos(x)Sin(y)


    Sin2x = 2SinxCosx
  7. Jul 21, 2011 #6


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    I don't think the question is easily answered. Would one characterize an ideal solitary wave as a "wave" or "waves"?
  8. Jul 21, 2011 #7
    That's why I said I don't have an answer, just my opinion.
  9. Jul 21, 2011 #8
    Well, amplitude, phase, frequency, wavelength, all these typical wave-ish terms are applicable to a "wave" (singular), which is a continuous sinewave. Or at least that's what comes to mind when you think about it in electronics domain.
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