Coombs MS in Physics on sound as a longitudinal wave

Investigating Student Understanding of Sound as a Longitudinal Wave
Earl C. Coombs, 2007 MS in Physics

The field of physics education research (PER) has highlighted the discrepancy between what is taught during traditional instruction in physics, and what students understand afterward. PER has also provided alternatives to traditional instruction that are research-based and have been shown to be more effective in bringing students’ level of understanding of physics more in line with that of the scientific community. One topic that has received attention is the propagation of sound. We confirmed that students in the introductory algebra-based and calculus-based physics courses at the University of Maine have difficulties with sound propagation similar to those documented by others. We found that a relatively small percentage of the students we interviewed from a calculus-based introductory physics course used the community consensus model of particles oscillating parallel to the direction of propagation. We identified three other mental models used by the interview subjects that have been described previously. The first was a model in which sound is considered to be an entity that passes through the medium without disturbing the particles of the medium. The second was a model in which sound is viewed as an entity that pushes the particles of the medium aside as it propagates. The third was a hybrid model in which the particles of the medium oscillate perpendicular to the direction of propagation. In an extension of the work by previous researchers in this area, we examined students’ ability to predict the points at which the particles of the medium have the maximum and the minimum magnitudes of velocity and displacement from their equilibrium positions. We found that students’ ability to do so was extremely limited. To improve student understanding of sound propagation, we developed an instructional tool in the form of a “tutorial” and evaluated its effectiveness through pre- and post-testing of students enrolled in an algebra-based introductory physics course. The tutorial constructed for this purpose was found to be successful in increasing the number of students that used the community consensus model when answering questions about sound propagation. It was less successful in enabling students to make accurate predictions about particle velocities and displacements.

Recommended Citation

Coombs, Earl C., "Investigating Student Understanding of Sound as a Longitudinal Wave" (2007). Electronic Theses and Dissertations. 314.

http://digitalcommons.library.umaine.edu/etd/314

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.

Menchen and Thompson on sound propagation and resonance

K. VP. Menchen and J.R. Thompson
Pre-service teacher understanding of propagation and resonance in sound phenomena
2003 Physics Education Research Conference Proceedings, in S. Franklin, K. Cummings, J. Marx (Eds.) AIP Conference Proceedings 720, 65-68 (2004)

Wittmann, Redish, and Steinberg on sound and curriculum development

M.C. Wittmann, E.F. Redish, and R.N. Steinberg
Understanding and Addressing Student Reasoning about Sound
International Journal of Science Education 25:8, 991-1013 (2003)