Enhance student learning by effectively combining representations and using visualisation to explain chemical concepts

The use of different representations and visualisation approaches to explain chemical concepts plays a key role in supporting chemistry students’ learning. Teachers’ decisions about which representations to use, and how to use them, are critical and depend on their own experiences and mental models of concepts. However, poor combinations of representations impede learning.

João Ferreira and Gwendolyn Lawrie investigated the use of combinations of representations from a series of lecture slides used for introductory chemistry at an Australian university. The representations – which included illustrations, internet images, diagrams, drawings and photographs – from a set of over 900 lecture slides created and revised over about 10 years and by 20 educators were characterised in accordance with the different frameworks. The study focused on the use of multiple representations that supported deep learning, drawing on work to identify examples in which knowledge could be applied by students to translate or construct references between known and unknown representations. Although active learning approaches had been introduced to the course over the years, much of the content was still presented as Powerpoint slides to large student cohorts.

An image showing multiple representations of a cat

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Selecting the right representation, and the right combination of representations, has a real impact on student learning

Unsurprisingly, symbolic representations were the most common, and some lecture slides contained as many as six representations. Topics were typically introduced by using symbolism that students were probably familiar with to reinforce and expand their representational fluenc. There were fewer examples of macroscopic and sub-microscopic representations, but there were links to simulations (sub-microscopic) on some slides and in-class demonstrations (macroscopic) were used on numerous occasions.

In addition, the authors point out the importance of educators’ gestures and real-time drawing to bring representations to life. These dynamic types of representation could form the basis of an interesting future study, although how you would go about categorising them would pose a challenge. However, the value of this study has already been demonstrated through its use in a review of the teaching materials examined, which resulted in improved strategies for combining representations and reducing cognitive load through the removal of extraneous examples.

Teaching tips

Although educators are becoming increasingly aware of the difficulties teachers and students alike face in managing representations (Johnstone’s Triangle model for example), it can be a challenge to improve your own work. Here are some tips:

  • Review your teaching materials and identify the challenges faced by students in interpreting the representations used. Consider the intended learning progression and the sequence in which different representations are introduced. 
  • Carefully scaffold learning by signposting familiar examples. Try to differentiate your teaching to meet the needs of individuals. It can take time for students to develop their own mental models. 
  • Beware of the cognitive load associated with multiple representations, particularly when introducing new concepts. Focus on the key learning points and remove any superfluous material. 

Finally, think about how you and your colleagues can support each other. Students often cite the teacher who somehow helped them make sense of chemistry. So, share ideas to improve your practice and enhance student learning.