Menchen MST: Sound propagation and resonance

K. VP. Menchen
Investigations of Student Understanding of Sound Propagation and Resonance
Unpublished M.S.T. thesis, University of Maine, 2005

This writing discusses the process of determining what students think about the phenomena of sound propagation and resonance using written pretests and interviews and then developing a curriculum based on analysis of student responses. We found that students and teachers alike generally have a difficult time understanding both propagation and resonance, which are foundational in this supposedly “simple science” of sound. The major difficulty that students encounter is their intuition that an object must vibrate only at its natural resonant frequency. Students tend not to put many limits on this rule, and misapply it to all kinds of situations, especially in propagation and resonance. Another common thought that students hold to is that a sound’s frequency will be altered by traveling through various materials. The research revealed many other misconceptions. Sound is a topic generally covered only at elementary school levels, and it is referred to in upper-level courses, as something already well understood to explain ideas pertaining to waves or quantum physics. It is disturbing to observe so many misconceptions in understanding sound, considering the accessibility of this topic.

The curriculum presented here has been developed and informed by these ideas to better help college-level students (mostly education majors) learn by taking into consideration their current understanding of how sound works. We target education majors primarily because they will presumably be passing along this information to the largest audience. The curriculum is used in a guided-inquiry, lab-based course that explores the fundamentals of physics in a hands-on style. My work starts with a preliminary version of curriculum, which has been improved over the past two years to more effectively teach students. The curriculum portions I’ve worked most on have been those that address the effects on the frequency of a sound with respect to resonance and propagation. Specifically, the curriculum has fostered improvements in students’ separation of the ideas of frequency and amplitude; their language when describing the motion of these two concepts; and improved but not flawless understanding of propagation, and how the medium affects the sound passing through. While improvements have been made, there are yet more developments to apply to the sections on propagation, as we continue to understand just what students struggle with.