In this paper, we discuss the first phase of a multiphase study aimed at investigating the dynamics of students’ knowledge construction in the context of unfamiliar physical phenomenon—microscopic friction. The first phase of this study involved the investigation of the variations in students’ mental models of microscopic friction. Clinical interviews were conducted with 11 students enrolled in conceptual modern physics to elicit their ideas and generate themes of explanations. A phenomenographic approach of data analysis was employed to establish the variations in students’ explanations. Results show that students’ mental models of friction at the atomic level are dominated by their macroscopic experiences. Friction at the atomic level according to most students is due to mechanical interactions (interlocking or rubbing of atoms)

Our previous research showed that students' mental models of friction at the atomic level are significantly influenced by their macroscopic ideas. For most students, friction is due to the meshing of bumps and valleys and rubbing of atoms. The aforementioned results motivated us to further investigate how students can be helped to improve their present models of microscopic friction. Teaching interviews were conducted to study the dynamics of their model construction as they interacted with the interviewer, the scaffolding activities, and/or with each other. In this paper, we present the different scaffolding activities and the variation in the ideas that students generated as they did the hands-on and minds-on scaffolding activities. Results imply that through a series of carefully designed scaffolding activities, it is possible to facilitate the refinement of students' ideas of microscopic friction.

In our pilot studies, we found that many introductory physics textbook illustrations with supporting text for sound standing waves of air columns in open-open, open-closed, and closed-closed pipes inhibit student understanding of sound standing wave phenomena due to student misunderstanding of how air molecules move within these pipes. Based on the construct of meaningful learning from cognitive psychology and semiotics, a quasiexperimental study was conducted to investigate the comparative effectiveness of two alternative approaches to student understanding: a traditional textbook illustration approach versus a newly designed air molecule motion illustration approach. Thirty volunteer students from introductory physics classes were randomly assigned to two groups of 15 each. Both groups were administered a presurvey. Then, group A read the air molecule motion illustration handout, and group B read a traditional textbook illustration handout; both groups were administered postsurveys. Subsequently, the procedure was reversed: group B read the air molecule motion illustration handout and group A read the traditional textbook illustration handout. This was followed by a second postsurvey along with an exit research questionnaire. The study found that the majority of students experienced meaningful learning and stated that they understood sound standing wave phenomena significantly better using the air molecule motion illustration approach. This finding provides a method for physics education researchers to design illustrations for abstract sound standing wave concepts, for publishers to improve their illustrations with supporting text, and for instructors to facilitate deeper learning in their students on sound standing waves.

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which is covered with sandpaper (see Fig. 1). In this phase, instruct students to drag the wooden block across the wooden plank starting from the surface with sandpaper all the way to the surface without sandpaper. The purpose of this activity is to activate students' prior ideas about friction. Exploration Activity 2 (cycle 1): Sketching pairs of sliding surfaces at atomic level In this exploration activity, ask students to sketch the sliding surfaces at the atomic level. Figure 2 shows a typical sketch by students of sliding surfaces (top represents the rough surface and bottom represents the smooth surface). The majority of students in the teaching interview activated their resource of "catching of ridges" in making sense of the increased friction between the wooden block and rough sandpaper surface. This association of increasing friction with the catching of ridges further leads students to make the association of increasing friction with increasing roughness.