Un-muddling models

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How to more effectively use models in the classroom

Students and teacher using computers

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Constructing and using models is a crucial skill for chemistry students. Relating observable macroscopic phenomena to their underpinning sub-microscopic processes is vital to explain chemical behaviour. Teachers regularly make use of models to achieve this.

A recent study from Mihwa Park and colleagues in the US explored the impact of computer models as formative assessment tools for understanding of the nature of models.

A recent study from Mihwa Park and colleagues in the US explored the impact of computer models as formative assessment tools for understanding the nature of models.¹

This project aimed to identify computer models and associated formative assessments that helped students understand the nature of models. Previous work has suggested flawed understanding of the role of models may undermine future learning.

Measuring models

The researchers developed ten sets of computer models covering a range of topics such as gases, bonding and equilibrium. Each set of computer models comprised two models: one illustrated macroscopic observations visually and the other demonstrated sub-microscopic interactions. Both allowed students to manipulate variables and observe outcomes on-screen.

Nine teachers in different schools and 174 students took part in experimental classes with 350 in control classes. Teachers received one day of training covering the nature of computer models, how to incorporate them in lessons and the rationale for formative assessment. Classroom experience ranged from five to 20 years. A doctoral student visited each school two or three times during the year to monitor implementation.

The teachers introduced relevant computer models for each topic. They prompted students to explore specific features of the model and adjust the variables to test a hypothesis. A worksheet provided by the researchers supported the activity. Afterwards, students completed online formative assessments that tested their understanding of matter, energy and models for each topic through multiple choice questions. The researchers generated scores, which teachers used to support feedback and subsequent differentiated teaching.

What they found

Increased use of models in teaching led to more students advancing their understanding of models. Using models in formative assessment was key to this.

However, students’ understanding of models as multiple representations was not significantly improved. The authors attribute this to a lack of explicit instruction to promote understanding. They speculate that disparities in participating teachers’ own knowledge of models may have been a factor. Meanwhile, classroom observations showed variation in the extent to which teachers used the data from assessments to inform later instruction.

This illustrated a limitation of the study. The researchers didn’t collect data on the teachers’ understanding of models and how to implement formative assessment effectively. They relied on years of experience as a proxy. Although the results are promising, it is clear teachers need to be supported if they want to use similar resources effectively.

Apply it in your classroom

There are many animations and simulations available online that teachers can use with students to illustrate chemical processes. PhET simulations, some of which were developed with the Royal Society of Chemistry, are particularly good examples to consider. Another personal favourite is a gas molecules simulation that illustrates the motion of particles and generates a Maxwell–Boltzmann distribution. You can control a number of variables and observe the outcome. Take care as these are just models. How ‘real’ they are varies, although that also presents learning opportunities.

There are many animations and simulations available online that teachers can use with students to illustrate chemical processes. PhET simulations,² some of which were developed with the Royal Society of Chemistry, are good examples to consider. Another personal favourite is a gas molecules simulation³ that illustrates the motion of particles and generates a Maxwell–Boltzmann distribution. You can control a number of variables and observe the outcome. Take care as these are just models. How ‘real’ they are varies, although that also presents learning opportunities.

Teaching tips

Do a thorough evaluation of any model before you show it to students. It’s particularly important to be mindful of any weaknesses or inaccuracies in the model.
Ask students to identify weaknesses and inaccuracies themselves, provoking insightful discussion during lessons. Another recent study explored the effect of comparing two animations where one contained a specific inaccuracy. This had positive impacts on learning.
Structure clearly how students are to use the model – for example, through the use of a worksheet. Many PhET simulations come with worksheets.
Plan explicit instruction to follow up students’ use of the model. Focus on your intended learning outcomes. Careful questioning will identify any alternative conceptions they have developed.