The learning design encompasses seven steps that is optimally delivered in a set sequence.

The Learning Design Sequence is illustrated as follows.

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WHAT THE STUDENTS DO
The learning design encompasses seven steps that are optimally delivered in the following sequence:

1. Observing

Students write observations for a laboratory-level chemical phenomenon such as a physical property of a substance (e.g. a metal conducts electricity) or a reaction between substances (e.g. precipitation of an ionic compound). This phenomenon is presented as a live demonstration, or with video (digital or analogue), and the lecturer ensures all observations are contributed by students.

2. Describing and drawing

Students attempt to explain their observations by drawing labelled molecular-level representations of the substance or reaction, and also describing their ideas in words. The lecturer needs to develop the ‘drawing literacy’ of students by discussing conventions (e.g. using relative sizes of atoms and ions, use of space-filling rather than ball-and-stick models, use of keys, etc.).

3. Discussing

Students receive initial feedback on their representations by discussion with one or more partners (or from an evaluation tool if available), with advice from the lecturer to identify key features of the representations that explain the observations. (Lecturer does not identify correct or incorrect key features at this stage).

4. Viewing molecular-level animations

Students see chemical phenomenon portrayed as a VisChem molecular-level animation, ideally three times:

• First, without commentary, with students encouraged to look for the key features of the animation.
• Second, in segments, each with narration by the lecturer drawing attention to the important key features.
• Third, in its entirety, with full narration.

5. Reflecting

Students reflect on similarities and differences between key features in animation and their drawings; amending their drawings accordingly.

6. Relating

Students are then encouraged to link the three thinking levels together by annotating a one-page handout; focusing at this point on using conventional chemical symbolism (formulas, equations, curly arrows, energy profiles) and mathematical relationships (stoichiometric ratios, rate laws, etc.).

7. Adapting

Students are then shown an analogous substance or reaction at the laboratory level; then asked to draw a representation, and the Activities 3–6 sequence above is repeated. This establishes whether the students can transfer their ideas to a new example.

SIGNIFICANCE OF ORDER
We are convinced that the constructivist approach is essential in order to promote effective, enduring cognitive change – particularly if the students have misconceptions. Simply showing the animation with narration (Activity 4) is much less effective.

CRITICAL ACTIVITIES
Students must be encouraged to communicate their prior conceptions before seeing the VisChem animation. This focuses their attention explicitly on any similarities and differences in key features between their prior mental models and the scientifically-acceptable model, and alerts them to any alternative conceptions in their model. The activities that draw attention to the key features in the VisChem animation (Activity 4) and encourage students to amend their drawings if necessary (Activity 5), together with repeated viewings of the animation at later dates, have also been found to be critical to the learning effectiveness of the design.

ACCESSIBLE RESOURCES

1. Laboratory-Level Video Showing Substance Properties and Chemical Reactions

Digital video (as QuickTime or AVI movies) showing chemical reactions is available in supplement packages with most first-year chemistry textbooks.

These resources are also available in analogue videotape format. For example, the VisChem “Reactions in Water” video series:

Tasker R, Bucat R, Sleet R, Chia W, Corrigan D (1996, 1997) The Molecular World of Reactions in Water, Part 2: Ionic Equilibrium, Acid/Base and Oxidation/Reduction Chemistry.

The advantage of this video series is that it also includes most of the VisChem animations.
However, students always prefer live demonstrations, providing they can see them clearly. This can be done using video-camera images projected onto large screens in lecture theatres.

2. Students’ Representations

The students’ representations are very valuable learning resources for other students, and for the lecturer, to identify alternative conceptions. They can be circulated as frame grabs from the Molecular-Level Construction Tool (explained below) or as hand-drawn diagrams.

3. VisChem Molecular-Level Animations

The VisChem animations are available on CD and videotape formats in the following media:

1. Tasker, R., Bucat, R., Sleet, R., Chia, W., & Corrigan, D. (1997). VisChem Resources — Learning Chemistry Through Visualisation of the Molecular Level.

This is a resource CD for chemical educators containing 82 animations in cross-platform QuickTime format (288Mb).

2. Tasker, R., Bucat, R., Sleet, R., Chia, W., Corrigan, D. (1996, 1997). Molecular World of Water Video (13 min). The Molecular World of Reactions in Water Part 1: Dissolving, Precipitation and Complexation Video (25 min). The Molecular World of Reactions in Water Part 2: Ionic Equilibrium, Acid/Base and Oxidation/Reduction Chemistry (33 min).

This is a series of three videos, designed for chemical educators, depicting chemical substances and reactions typically covered in an introductory chemistry course.

These media are available in Australia and New Zealand from Video Education Australia, see http://www.vea.com.au, search for "Reactions in Water", for CD and videos; and distributed in the US by Films for the Humanities and Sciences in NTSC video format only, see http://www.films.com, for item number 7748 with title "The Molecular World of Reactions upon Water".

A screen shot illustrating a VisChem animation.

Each VisChem animation on the CD has a reference code so it can be located and copied into presentation software like PowerPoint.

The animations are also available in compressed Web-deliverable versions for use with Acrobat documents on course web sites (e.g. WebCT). This allows them to be incorporated into online flexible-learning resources.

4. Interactive Multimedia Support Resources

There are a number of interactive, CD and online support resources produced with CADRE design and published internationally to supplement and complement textbooks by WH Freeman & Co., New York. The WH Freeman web sites are supplements for their textbooks, but they are not restricted to adopters of these books. The VisChem animations are presented in the ‘three-thinking-level’ context, often with lab-level video.

Example 1: Tasker, R. (1999). Visualisation CD for Atkins, P and Jones, L Chemistry: Molecules, Matter and Change 4th Ed.

This resource comprises an interactive CD supplement with five major topic areas using VisChem animations, with interactive questioning, and molecular-level constructions.

Two screen shots are illustrated below.

Screen shot of a student's that shows misconceptions specifically targeted in the animation.

Screen shot showing how an animation is displayed. Voiceover is also included.

Example 2: Tasker, R. (2002). Web Site. General Chemistry. An American Chemical Society Project. 1st Ed.

This resource comprises Web-deliverable modules on selected topics in each chapter, that use interactive animations and simulations to develop thinking at the molecular level. The major emphasis is on molecular-level visualisation.

See http://www.whfreeman.com/acsgenchemhome/, click on “Tutorials”.

After clicking on the top-right animation frame, the VisChem animation appears embedded in an interactive interface. Students are encouraged to engage with the animation by answering questions and clicking on hotspots:

Example 3: Jones, L., & Tasker, R. (2001). CD and Web Site. Bridging to the Lab: Media Connecting Chemistry Concepts with Practice.

This resource contains pre- and post-lab modules for selected laboratory experiments in university-level general chemistry, containing VisChem animations, with student tracking.

See http://whfreeman.com/bridgingtothelab/.

Example 4: Tasker, R. (2001). Web Site for Atkins P and Jones L Chemical Principles, the Quest for Insight 2nd Ed.

This resource provides web-deliverable versions of VisChem animations to complement and supplement Figures in the textbook. These can be downloaded directly from this site.

See http://www.whfreeman.com/chemicalprinciples/ and go to “Animations”.

Example 5: Tasker, R. (2001). CD and Web Site for ChemCom — Chemistry in the Community. An American Chemical Society Project. Heikkinen H ed. 4th Ed. Suitable for upper high-school level.

This resource provides web-deliverable modules using VisChem animations and interactive graphics to develop thinking at the molecular level. The major emphasis is on applications to everyday contexts.

See http://www.whfreeman.com/chemcom and go to “Interactive ChemCom Media”.

RESOURCES IN CONTEXT
Chemistry involves interpreting visible changes in matter at the concrete laboratory level (e.g. colour changes, formation of solids, boiling) in terms of changes in structure and processes at the invisible molecular level (including atoms and ions). These changes are then represented at an abstract symbolic level in two ways: qualitatively, using specialised notation, terminology, and symbolism; and quantitatively, using mathematics (equations and graphs).

The need to be able to move between the ‘three thinking levels’, first described by Johnstone (1991), is a major problem for students learning chemistry. This learning design explicitly encourages students to learn new chemistry concepts by thinking about them at the laboratory, molecular and symbolic levels.

Frame from the VisChem presentation on ice melting, showing the three ‘thinking’ levels - the symbolic (chemical equation), laboratory (ice melting in beaker), and molecular (depicting ice on the left and liquid water on the right).

Due to a shortage of high quality resources that portray the molecular level, most chemistry teaching only occurs at the laboratory and symbolic levels, in the hope that the students’ mental models of the molecular world will ‘develop naturally’. Students are left to construct these models from the static, often oversimplified two-dimensional diagrams in textbooks, or static, often confusing ball-and-stick models, or their own imagination. However, there is convincing evidence that most student difficulties and misconceptions in chemistry stem from inadequate or inaccurate models of the molecular world.

The aim of the VisChem project has been to produce multimedia resources (animations, video, text and sound) to explicitly link the three levels - the molecular, laboratory, and symbolic - for a variety of difficult topics in chemistry. The novel resources have been the Quicktime molecular animations which represent substances in the solid, liquid, and gaseous states, during phase changes (e.g. melting), and when they react together. In addition to a stand-alone format, these animations have also been integrated into a series of videos that present them in the context of the three levels.

Reference:

Johnstone, A. H. (1991). Why is Science Difficult to Learn? Things are Seldom What They Seem. Journal of Computer-Assisted Learning, 7: 701-70.

VARYING THE RESOURCE SET
The VisChem animations are a core resource because they use consistent visual conventions over a wide variety of substances and reactions commonly encountered in first-year chemistry. However, it is the way these resources are used that is much more important than the resources themselves.

SUPPORTS SUPPLIED

Supports provided include: the lecturer, a visual summary handout to assist the students to understand the relationship between the physical phenomenon; its molecular-level representation; and the symbolic notation.

These support mechanisms are elaborated as follows.

1. Lecturer demonstration of chemical phenomenon

The lecturer begins by presenting a chemical phenomenon, preferably in a live demonstration, or if this is not appropriate, using digital or analogue video. Examples could include pouring liquid oxygen into a beaker, decolourising iron(II) thiocyanate solution by adding fluoride, or stretching plastic Gladwrap® to tearing point. The exercise is to list the significant observations, and this is not always a trivial activity.

2. Lecturer discusses molecular-level representation conventions

The lecturer needs to discuss with students how atoms, molecules and ions can be portrayed in a ‘snapshot’ in time. Artistic license (e.g. colouring different atoms differently, use of ball-and-stick vs. space-filling representations) needs to be balanced against scientific accuracy (relative size, crowding, average orientation relative to neighbours, etc.). The major emphasis should be on communicating the key features of a molecular-level representation effectively.

Sloppiness here needs to be compared with lack of care with language in describing a scientific phenomenon. Resistance to drawing as a mode of communication needs to be likened to resistance to communication in words. There is a need to develop a kind of ‘drawing literacy’, using the kind of judgement used by a chemist in the lab – sometimes there is a need for rigorous attention to detail, at other times the need is less.

Note however, that communication should be in both text and graphics.

3. Focus on "Key Features"

Multi-particulate representations are complicated so the lecturer needs to focus student attention on clearly communicating the key features necessary to explain the observations of the phenomenon.

4. Presenting the animation

If time permits, the VisChem animation should be shown three times:

• First, without commentary, with students encouraged to look for the key features of the animation without assistance.
• Second, in segments, each with narration by the lecturer drawing attention to the important key features.
• Third, in its entirety, with full narration.

If students are focused on comparing features in their representation with those in the animation, the impact is likely to be greater. However, it is essential for the lecturer to identify all the key features explicitly. Repeat viewing is advisable, but this could be left to the other support resources (Resource 6) for another time.

5. Identifying alternative conceptions

Students often do not realise they have alternative conceptions, or have communicated alternative conceptions, in their drawings. The lecturer needs to encourage peer criticism for this purpose.

6. Encouraging seamless movement between thinking levels

Students need to be encouraged to relate the three thinking levels in order to make sense of what they see in terms of what is happening at the molecular level, and interpret the conventional chemical symbolism accordingly.

We have found that students need a physical memory of the learning experience in the form of some kind of handout. A visual summary that they can annotate is essential. An example is illustrated as follows:

This summary would only be handed out at the end of the teaching sequence.

7. Providing opportunities to demonstrate application and transfer of visualisation skills

The lecturer needs to provide subsequent opportunities for students to communicate their models of the molecular world in a variety of ways such as in lab reports, posters, assignments and test questions. If students do not think they will be assessed on these skills, they are not worth the investment of time and cognitive effort.

SIGNIFICANCE OF SUPPORT STRATEGIES
In our view, a skilled educator should take students carefully through a mental journey requiring active thinking

• From concrete to abstract levels (Support Elements 1 – 7).
• With focus on identifying key features of the molecular level (Support Elements 3 - 5).
• Identifying alternative conceptions, if any (Support Element 5).
• Showing both detailed and global perspectives (Support Element 6).
• application of visualisation skills to new chemical systems (Support Element 7).

SUPPORT STRATEGY ADAPTATION
The involvement of a skilled educator in this learning design is considered critical. An interactive Molecular-Level Construction has been developed to provide an online tool to provide evaluation of the student's representation of an ionic solution. This will be evaluated to see if a flexible learning online design is effective without the need to involve a lecturer.

Our experience has shown that streamlining the design by eliminating steps to save time is much less effective unless students are well-practised in the skills required.