Many students do not fully understand that sound is caused by vibrations

For example, some students believe in the existence of some sort of sound particle. Some younger students, when asked to consider an instrument producing sound, will imply sound is constructed by instrument and released by a person or force. Following this same reasoning, they may believe that different sounds are made of different types of matter. Additionally, some students believe that sound is made by vibrations only in instruments where vibrations can be seen and therefore believe another mechanism is required as an explanation (without vibrations). Even if students are aware of the particle nature of gases in the air, some will not intuitively understand that the air can carry vibrations and hence recognise that sound comes from visible vibrations of an object but not that this vibration is transferred to the air.

Resources to Address This

• Sounds and vibrating sources  (5-11)

  Ref - SPT HS02 TL02  also found at So01 TL03

  In some situations the vibrating object is obvious; in others it is less so. Where the vibration is less obvious, pupils tend to revert to ad-hoc explanations for the generation of the sound, often focusing on human action. For example, The hammer makes the bang because you hit the wood hard with it. The learning challenge for pupils is to develop the general idea that all sounds are produced by vibrations.

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• How vibrations travel (14-16)

  Ref - SPT Ra01 PN02

  So, what's doing the vibrating – that is, what is the source setting into repetitive motion, where it is sensible to be able to say that it has both a frequency and an amplitude? Let's start with light and with sound. These are very different – physically different. One needs tangible particles to vibrate; the other needs only an electromagnetic field. Some of the properties of these two kinds of vibrations were elucidated in the SPT: Sound and SPT: Light topics. These two can serve as prototypes: sound for mechanical vibrations; light for the whole electromagnetic spectrum.

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• Episode 309: Generating waves (16-19(

  Ref - TAP; Teaching vibrations and waves;

  Now use the slinky spring to show longitudinal pulses. Fix one end to a retort stand, and quickly push the free end back and forth, along the length of the spring. Watch the motion of the marked coil. It moves to and fro as the disturbance is passed along.

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References

The following studies have documented this misconception:

• Barman, C.R., Barman, N.S. & Miller, J.A. (1996) Two teaching methods and students' understanding of sound. School Science and Mathematics, 96 (2),

  p63.

  Review sheet

• Houle, M.E. and Barnett, G.M. (2008) Students’ Conceptions of Sound Waves Resulting from the Enactment of a New Technology-Enhanced Inquiry-Based Curriculum on Urban Bird Communication. Journal of Science Education Technology, 17,

  242-251.

  Review sheet

• Eshach, H., Lin, T-C. and Tsai, C-C. (2017) Misconception of Sound and Conceptual Change: A Cross Sectional Study on Students’ Materialistic Thinking of Sound. Journal of research in science teaching, 5 (55),

  664-684.

  Review sheet

• Eshach, H. & Schwartzb, J. L. (2006) Sound Stuff? Naïve materialism in middle-school students’ conceptions of sound. International Journal of Science Education, 28 (7),

  33–764.

  Review sheet