"VisChem: Visualising Chemical Structures and Reactions at the Molecular Level to Develop a Deep Understanding of Chemistry Concepts"

When covering a topic in chemistry that requires an accurate mental model of the molecular world, a typical learning experience in a face-to-face lecture context would involve students:

• Observing a chemical phenomenon (chemical reaction or property of a substance) as a lecture demonstration, lab activity, or audiovisual presentation; and documenting their observations in words and/or diagrams.
• Describing in words, and drawing a representation of what is occurring at the molecular level to account for the observations; with the lecturer explaining the need for drawing conventions (e.g. to indicate relative size, movement, number, crowding).
• Discussing their representation with a peer, with the aid of the lecturer’s advice to focus on the key features of the representation that explain the observations.
• Viewing a VisChem animation portraying the phenomenon at the molecular level, first without, then with narration by the lecturer, and looking for key features.
• Reflecting with the peer on any similarities and discrepancies between their own representations and the animation, and then discussing these with the lecturer.
• Relating the molecular-level perspective to the symbolic (e.g. equations, formulas) and mathematical language used to represent the phenomenon.
• Adapting their mental model to a similar phenomenon with an analogous substance or reaction.

Key criteria for success of this design to promote enduring cognitive change are:

• The constructivist approach that focuses attention on the student’s prior mental model.
• Focusing attention on key features.
• Repetition of the approach throughout the subject.
• Practice, application, and explicit assessment of the molecular-level visualisation skills developed.

This exemplar has been selected for inclusion for the following reasons:

• The focus of the learning design is to facilitate learners' understanding of phenomena that cannot be physically seen. The learning design sequence assists learners to correct misconceptions and the use of animation enables learners to visualise the non-visible properties of the phenomena.
• The learning design has undergone extensive evaluation that attests to its effectiveness.
• The learning design has developed and evolved since its initiation in the early 1990s when its development was assisted with CAUT funding in 1993/1994 (Australian Government Committee for the Advancement of University Teaching).

To further support students' construction of a mental model of the molecular-level representation of chemical solutions, a software tool titled: Molecular Construction Tool has been developed by this project. It is accessable from the "Cross-links" below or from the "Tools" section of this web site.

In addition, this learning design has been redeveloped in the form of a generic Guideline as the constructivist approach of focusing attention on the learner's prior mental model can be applied in different disciplines and contexts. The generic Guideline is accessable from the "Cross-links" below or from the "Guides" section of this web site.