Effects of Context on Students’ Molecular‐Level Ideas

Abstract

In the studies reported here, we investigate the effects of context on students' molecular-level ideas regarding aqueous solutions. During one-on-one interviews, 19 general chemistry students recruited from a two-year community college and a research university in the United States were asked to describe their molecular-level ideas about various aqueous solutions in the contexts of conductivity and boiling-point (BP) elevation. Results indicate that context is important for determining the molecular-level ideas that students express. Specifically, students were significantly more likely to draw pictures of aqueous NaCl as separated ions in the conductivity context compared with the BP elevation context, for which they more often drew "molecular" NaCl. This phenomenon was particularly striking because the students drew molecular-level NaCl(aq) pictures in the BP elevation context just minutes after completing the identical task in the context of conductivity. Additional data from laboratory assignments and course examinations further indicate that, even if students are able to correctly represent the molecular level in some contexts, their knowledge may remain inert in slightly different contexts. The results emphasise the importance of the context dependence of molecular-level ideas and have implications for designing instruction in which students develop robust, coherent understandings that they can apply appropriately in new contexts.

A Case Study of the Common Difficulties Experienced by High School Students in Chemistry Classroom in Gilgit-Baltistan (Pakistan)

“…A large number of studies in international context as well as in Pakistan have investigated students' misconception around a wide range of concepts in secondary chemistry. Some of these concepts are atoms and molecules (e.g., Griffiths & Preston, 1992;Harrison & De Jong, 2005;Teichert, Tien, Anthony, & Rickey, 2008); gases and related concepts such as temperature, pressure, kinetic molecular theory, diffusion (e.g., Benson, Wittrock, & Baur, 1993;Krnel, Watson, & Glazar, 1998); chemical bonding (e.g., Coll & Taylor, 2001;Frailich, Kesner, & Hofstein, 2009;Othman, Treagust, & Chandrasegaran, 2008); solution, solubility, and solubility equilibrium (e.g., Ebenezer & Erickson, 1996;Pinarbasi & Canpolat, 2003;Raviolo, 2001); electrochemistry and related concepts (e.g., Coll & Treagust, 2003;Sanger & Greenbowe, 1997;Taber, 1997); structure and properties of molecular and ionic compounds (e.g., Butts & Smith, 1987); particle theory (Johnson, 1998a(Johnson, , 1998bMursaleen, 1999); chemical equilibrium (e.g., Banerjee, 1991); acids and bases (e.g., Drechsler & Schmidt, 2005;Hand, 1989;Lin & Chiu, 2007;Nakhleh, 1994;Schmidt, 1995).…”

How a Qualitative Study with Chemistry Instructors Informed Atomic Level Animation Design

“…Teichert at al. (32) concluded that very few students were able to express correct molecular-level ideas regarding ionic compounds and molecules dissolved in water; however, they indicated that context may activate specific molecular-level ideas and lead to improved performance.…”

“…Narration by Dr. Ann Ion helps clarify what the viewer is seeing and highlighting techniques are also used to scaffold the process. Studies indicate that beginning general chemistry students have a limited understanding of the molecular and electrolytic behavior of strong electrolytes, weak electrolytes and non-electrolytes (32,(39)(40)(41)(42)(43)). Many students will express only the simple whole number ratio of ions when constructing atomic level pictures.…”

“…In this section, the focus shifts to examine how to present the animations to foster learning, because animations shown in isolation can be difficult for students to understand. Teichert, Tien, Anthony and Rickey report that that there is a specific connection between students' understanding of conductivity context and activation of students' molecular-level ideas about separated ions in solution (32). In order to create context for the animations and help students to build connections between the macroscopic and atomic level representations, the animations are embedded in a tutorial framework.…”

Importance of Considering Longitudinal Trajectories in Education Reform Efforts

“…Considerable efforts have been made over the years to understand the nature of cultural capital in science education (13). For example, it has been argued (14) that for most students, the science classroom represents a sub-culture that is quite distinct from their daily experience (with family or peers, for instance) and one result is that many students routinely compartmentalize the science knowledge (15)(16)(17). The challenge of simultaneously supporting content-based strategies for education reform with other cognitive strategies or socio-cultural strategies remains an important one to consider.…”