AUC Academic Conference 98

Introduction

A deep understanding of chemistry involves being able to interpret visible observations at the laboratory level (eg. colour changes, formation of solids, boiling) in terms of structure and processes at the invisible molecular level. Only then can these observations be communicated in a meaningful way at the symbolic level (eg. chemical formulas). This is the central philosophy of the VisChem project.

Figure 1. The three thinking levels in chemistry as they apply to a chemical reaction

Many of the misconceptions that students acquire results from a poor model of the molecular level. At the 1995 and 1996 AUC Academic Conferences, we reported on the educational rationale for, and production of, unique 3D animations portraying chemical structures and processes at this level, and an interface to access them.

Since then we have evaluated these resources using pre- and post-questionnaires, focus group discussions, and structured interviews (with up to three students at a time). The results have convinced us of the effectiveness of these animations to aid understanding of fundamental concepts in chemistry, and correct misconceptions.

In this paper we report on our latest work applying QuickTime VR to two challenges for chemical educators:

to show the relevance of chemistry, by linking some of the abstract concepts of the molecular level to real objects and processes in the everyday world
to help students to mentally transform the abstract representations (eg. chemical formulas) of molecules in textbooks, into images of atoms connected together in clusters with particular shapes

Linking the Molecular Level to the Everyday World

We are developing an interactive interface with a running shoe as a QTVR object. The user can watch this shoe splashing through water (and not getting wet), landing on a hard surface and distorting (and not bouncing back into shape), heating up (and not melting), and cooling down (and not freezing).

These and other properties of the materials in a running shoe are quite familiar, but the reasons why these materials have these desirable properties have a chemical basis.

By clicking on hotspots on the shoe, the user is taken to a new level of perception (the molecular level), where the everyday action (eg. heating up) is shown in molecular detail (eg. molecules vibrating with more energy).

This appreciation of the link between molecular architecture and everyday behaviour provokes the question whether other polymers could be designed with superior characteristics - this is the job of development chemists.

Multiple Representations of Molecules

One of the most difficult problems for chemistry students is linking two-dimensional formula representations to three-dimensional molecular structures. We have developed a novel way to link the symbolic and molecular levels by using the QTVR interface. We exploit the ability to move in the 'forward' (right) or 'reverse' (left) directions in a movie, with the ability to jump up or down to the equivalent frame in another movie running parallel to the previous one:

The student click & drags the cursor, up or down to move between representations (Figs 2, 3), and left or right to rotate or 'manipulate' the molecule.

Fig 2 Multiple representations of (2R)- bromobutane

Fig 3 Multiple representations of acetone

By seamlessly moving between these representations students can see the same event (eg. a molecule rotating or 'flipping') as a changing chemical formula, a ball and stick model, a computer-generated electron density surface, or as specialised chemical notation. In this way students can learn nomenclature rules by asking and answering 'what if?' questions.

References
Ben-Zvi, R, Eylon, B and Silberstein, J. (1987). Students Visualisation of a Chemical Reaction. Education in Chemistry July, 117-120.

Tasker, RF., Bucat, RB., Sleet, RJ. and Chia, W. (1996) Research into Practice: Improving Students' Imagery in Chemistry. Research in Science Education. Submitted for publication.

Contact details
For more information on the VisChem resources,
look at our Web site
vischem.cadre.com .au

or contact
Dr Roy Tasker
School of Science,
UWS Nepean,
PO Box 10, Sydney,
Australia 2747;
Fax: 61-47-360-713
Email: r.tasker@uws.edu.au

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