The Chemical Equilibrium research project is a continuation of previous work which had as its goal the understanding of an explanatory metaphor for the construction of chemical concepts. This project follows similar work on the construction of mental models of mental molecular rotation. Using the constituents of a mental model (Lesh, et al., 2000), we have shown that learners construct their mental models of five constituents: referents, symbols and their meanings; relations between referents; rules and syntax for communication of relations and referents; results of manipulations of referents and their relations; and operations, which permit the use of a mental model as a thinking tool. Our research has been reported twice at the Biennial Conference on Chemical Education, once in 2006 and again in 2008.
Our current work focuses on the mental models learners construct of chemical equilibrium. We use thought revealing activities (Lesh, et al., 2000) and think aloud protocol (Simon & Ericsson, 1993) to elicit the constituents of a mental model. Participants are placed in a situation in which they must use a simulation of a dynamic equilibrium written using netlogo to answer questions posed in an interview protocol. As of May 2009 we have had three participants, each of who have been interviewed twice. We are in the process of analyzing the data streams from the interviews for constituents of the participants' mental models of chemical equilibrium. This work has been presented by two undergraduate researchers, Heather Wagoner and Ashley Rossi, at the Undergraduate Research Forum, 2009, at Indiana University of Pennsylvania.
The undergraduate researchers reported the following preliminary findings for participants' mental models of chemical equilibrium.
Referents: reactants, products, blue circles, yellow circles, A, B, double arrows, NaCl, NaOH, HCl, H 2 O, reaction, concentration, rate, forward, backward, …
Relations: reactant/product, forward/backward, separation/combination, slow/fast, dilute/concentrated, …
Rules/syntax: the forward reaction must go at the same rate as the backward reaction; a blue and a yellow make a green and a brown; a green and a brown make a yellow and a blue; the reactions do not stop; …
Results: blues and yellows react to make greens and browns which then react to make blues and yellows; the reactions are dynamic and thus will not cease; …
Operations: heat drives the reactions; …
As one can see, we are understanding the construction of participants' mental models of chemical equilibrium and, along with our previous work and the other research projects in the current NSF grant, we feel these mental models can be used as probes of the status of student learning and thus can be used to evaluate inductive teaching methods.
Lesh, R., Hoover, M., Hole, B., Kelly, A., Post, T. Principles for developing thought-revealing activities for students and teachers. In Handbook of Research Design in Mathematics and Science Education ; Kelly, A., Lesh, R., Eds.; Lawrence Erlbaum: Mahwah, 2000; pp 591-645, especially p. 609.
Simon, H. A.; Ericsson, K. A. Protocol Analysis: Verbal Reports as Data; revised ed. MIT Press: Cambridge , Mass, 1993.