The educational foundation for this learning design is based on combining three models for learning:

1. Johnstone’s (1991) three-thinking level model

This is the basis for the activity sequence in the learning design – from the concrete laboratory-level phenomenon, to the more abstract molecular level, and then to the most abstract symbolic and mathematical levels. Activity 6 (In the Learning Design Sequence) summarises the three levels together.

2. Johnstone and El-Banna (1986) information processing model

This model suggests that perception of new information is filtered according to established ideas stored in the long-term memory, and held for short-term processing in a ‘working space’. This space has limited capacity (7±1 ‘bits’ of information), and the processed ideas need to be stored quickly in the long-term memory, or they are discarded, before new information can be processed.

Johnstone and others have applied this model to explain student difficulty in practical work (e.g. too much information ‘noise’ exceeds working space capacity, clouding the ‘signal’), lectures (e.g. attention breaks related to lecturer’s rate of information delivery), and problem solving (e.g. complex problems exceed the working space, irrespective of chemical understanding).

Sharing the student’s representation with a peer to identify key features (Activity 3) is designed to activate the perception filter; the stepwise presentation of the visually-complex animation (Activity 4) is designed to ease the load on the working memory; and the reflection and summary activities (Activities 5 and 6) are designed to encourage cross-linking in the long-term memory.

3. Social Constructivist Model

This model, described by Driver and Oldham (1986) and others, suggests students construct new understanding most effectively after they have considered their current understanding, and have social interaction with their teacher, peers, or even a computer (!). Through activities that challenge pre-existing ideas, students restructure their own understanding. Students are then given opportunities to apply their new understanding, then compare this with their prior understanding.

The most effective chemical phenomena used in the learning design are those that create a cognitive conflict with an inadequate mental model held by a student, creating dissatisfaction with their current view. The time and effort taken to allow students to consider their prior views (Activities 2 & 3), and reflect on discrepancies between key features in their representation and the animation (Activities 5 & 6), are worthwhile according to this model, which is consistent with our experience with achieving successful cognitive change.

There is convincing evidence that most student difficulties and misconceptions in chemistry stem from inadequate or inaccurate models of the molecular world. This was the basis for focusing on molecular-level visualisation, and producing the VisChem animations in the first place.

References:
Johnstone, A. H. (1991). Why is Science Difficult to Learn? Things are Seldom What They Seem. Journal of Computer-Assisted Learning, 7: 701-703.

Johnstone, A. H., & El-Banna (1986). Capacities, Demands and Processes - a Predictive Model for Science Education. Chemistry, May Issue, 80-84.

Driver, R., & Oldham, V. (1986). A Constructivist Approach to Curriculum Development in Science. Studies in Science Education, 13: 105-122.

ORIGIN OF THE LEARNING DESIGN
The need for the VisChem animations became apparent from a frustration with teaching students about the 3-D, dynamic molecular world using 2-D, static teaching resources.
However, an early lack of success in achieving enduring cognitive change in the development of students’ mental models led me to the importance of how the VisChem animations are used.

TIMES THE LEARNING DESIGN HAS BEEN USED

I have developed the learning design over the last eight years but I have only used the latest design in the last two years. I have used the sequence about 20 times in the last year with various audiences.

MODIFICATIONS SINCE FIRST USE
The most significant change since its inception in 1994 was taking the time to elicit the student’s prior views before showing the VisChem animation, and developing assessment items that genuinely probe student understanding of the molecular world. The constructivist approach, and convincing students that the skills developed were assessable, greatly increased the effectiveness of the design.

DISSEMINATION
Aspects of the learning design using the VisChem animations have been simulated in the interactive multimedia CD and Web resources listed in the Resources section of this document.

RESEARCH CONDUCTED ON THE DESIGN
A Ph.D study by Rebecca Dalton has focused on the evaluation of the VisChem animations and their effectiveness in assisting students to build mental models of the molecular world.

The following summary of her findings resulted from pre- and post-questionnaires, followed up with selected one-to-one interviews. Rebecca's preliminary findings are that “animations used as part of the recommended teaching sequence (where the aspects of the particle level of matter are emphasised) helped the majority of students to:

• Develop images of the particulate world.
• Improve their existing mental models of molecular and ionic substances - increased number of key images in representations (from pre- and post-test comparisons).
• Reduce or eliminate certain misconceptions, e.g. particles in solids are static, "stuff" exists between molecules in a molecular compound.
• Increase their confidence in their mental imagery in chemistry.
• Improve the clarity of their mental images.
• Visualise similar substances not depicted by VisChem animations.
• Confirm their already-existing ideas about the particle level of matter.
• Communicate their ideas about the particle level of matter.

From a longitudinal study (3rd Year students 1999 and 2000, past graduates - 30 students):

• Out of 30 students who had been taught using the animations in first year, 28 report having at least a moderately-clear and vivid recollection of the VisChem animations, even at least two years after seeing them.
• Out of all animations shown in first year, aspects of animations involving water are recalled most vividly (this also seems to be the case for first year students in 2000).
• All students who reported recollection of animations (29) felt that the animations helped them in first-year chemistry and subsequent years in their chemistry degree.

Sample feedback from student interviews includes

Improved visualisation:

• "It added colour to my images and more clarity".
• "...helped me to turn words into mental pictures".
• "The animations give a guide that can be applied in other situations, it's the visualising and thinking about them which made them most useful".

Interactions and movement:

• "They helped me visualise interactions of different molecules and did enable broader thought as I had the actual images in my mind I could substitute other molecules for and play in my mind."
• "...helps me visualise interactions between molecules".
• "It allowed me to picture processes".
• "Everything is moving".

Made learning easier:

• "...made work easier to understand, than just with text-books or overheads".
• "...made a better visual understanding of the structures (as if they are tangible).
• "...make you visualise something which you cannot always see".
• "I am not a visual learner...a carefully explained animation (as was the case in first year) is able to "get through" to anybody".
• "...brought a sense of realism to chemistry".

Increased interest:

• “...made it [chemistry] more interesting, meaningful”.
• “...increased interest in chemistry”.

DESIGN EFFECTIVENESS VERSUS INTENDED OUTCOMES
The learning design works very well if the essential features of the design are implemented. Rebecca’s research, the student satisfaction surveys, and the assessment results indicate students enjoy the subject, and are understanding difficult concepts better than they have done in past years. This may not necessarily be due to the learning design.

LEARNER ENGAGEMENT SUPPORT
The constructivist approach requires taking prior experiences into account, the three-thinking-level strategy provides multiple perspectives, and peer interaction and feedback are essential elements in the design.

Assessment tasks draw explicitly and implicitly on the skills developed, and students are encouraged to reflect on the learning experience (Activities 5 & 6).

Rebecca Dalton’s research suggests that the cognitive changes she has observed result from student engagement with the activities.

The flexible learning resources being developed will provide student control.

ACKNOWLEDGMENT OF LEARNING CONTEXT
The learning design acknowledges the learning context by assisting students to see how their learning can be used in situations other than the ones given. Assessment taks require students to demonstrate their improved confidence in explaining phenomena at the molecular level.
To the best of my knowledge there are no cultural assumptions built into the learning design.

HOW THE DESIGN CHALLENGES LEARNERS
A vital feature of the learning design is that students are given the opportunity to question their knowledge,enabling them to become self-critical of the limits of their knowledge base and misconceptions.

OPPORTUNITIES FOR PRACTICE
To ensure students are convinced of the importance of developing accurate mental models of the molecular world, it is essential that there is a clear alignment between the activities conducted and how the students are assessed. Students are encouraged to articulate to themselves and others (peers and lecturers) what they are learning. If they take full advantage of the support multimedia resources- including the molecular construction tool being produced- sufficient practice is provided to enable expertise to be realised.