Many students think that the amplitude (like wavelength) is in some way proportional to frequency and speed.

Light, Sound and Waves

Misconception RESEARCH REVIEW

Resources to Address This

  • Taking care with technical terms - amplitude (14-16)

    Ref - SPT Ra01TL05

    Being precise when talking about amplitude

    Wrong Track:The amplitude of a sound wave is how big it is.

    Right Lines:The amplitude of a sound wave is the difference in density at the points of zero and maximum displacement of any point on the wave.

    View Resource
  • "Estimating wavelength, frequency, and velocity of ripples (11-16)

    Ref - Practical Physics; Waves; Measuring waves in a ripple tank;

    It should be possible to calculate whether frequency x wavelength is near to the measured value for the velocity.  By elimination, it can be shown that amplitude does not influence frequency.

    View Resource
  • "Episode 311: Speed, frequency and wavelength (16-19)

    Ref - TAP; Teaching vibrations and waves;

    This episode considers how these three quantities are linked by the wave equation v = f ×  λ , measuring f using an oscilloscope, and measuring the velocity of sound in free air.  Again it can be shown there is no link between frequency and amplitude.

    View Resource

References

The following studies have documented this misconception:

  • Pejuan, A., Bohigas, X., Jaen, X. and Periago, C. () Misconceptions about sound among engineering students, Journal of Science Education and Technology, 21,

    669-685.

    Review sheet

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