Support students to make sense of models

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How to use your subject and pedagogical knowledge to transform your students’ understanding of tricky concepts

Researchers have reframed how chemistry teachers’ pedagogy and students’ conceptual learning is supported. The researchers, Meng-Yang Wu and Ellen Yezierski from Miami University, focus on an underexplored aspect of pedagogical content knowledge (PCK) called transformation. This mechanism converts subject matter knowledge (SMK) into enacted PCK (ePCK). Think of the transformation of SMK into ePCK as you thinking your way from your own understanding to the thought processes and motivations of learners.

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Ignite student understanding of difficult concepts with this take on combining your subject and pedagogical knowledge

The research introduces a conceptual framework called pedagogical chemistry sense-making (PedChemSense). This framework gives guidelines for teachers to transform their chemistry understanding into teaching practice. The resulting practice improves students’ chemistry sense-making and explanations.

PedChemSense requires the understanding of reasoning and sense-making from the perspectives of the teacher and their students. The researchers define pedagogical reasoning as teachers engaging their professional knowledge during lesson planning. Connecting different concepts together is student reasoning. Sense-making involves using scientific ideas and prior experiences to figure out complex phenomena. Pedagogical sense-making happens when teachers create uncertain moments in the classroom. You can plan which ambiguities and decisions students will encounter in a lesson and adapt to students’ emergina ideas in these uncertain moments.

Teaching tips

To prompt students to think about their own understanding of concepts, use Vischem’s Introductory video or this video about a learning design for a redox reaction. You could share clips from the videos in a lesson.

The dissolution of sodium chloride in water is a simple context that illustrates the researchers’ recommended teaching practices; you could show your students this useful Vischem animation of it. However, you could also adapt the approach for any example where a particulate-level animation is used.

Ask students to observe the phenomenon, ie sodium chloride dissolving in water in a beaker. Use a thermometer to demonstrate that the process is endothermic – the temperature of the solution formed is slightly cooler than the initial temperature of the water. Then ask students to share ideas about the reasons for this.
Ask students what (aq) means in terms of the number of solvating water molecules and how they are oriented around the ions. The reasons for the particles’ orientations could be discussed in more detail, ie the polarity of water molecules and the charges of the ions.
Ask students to consider what information is not conveyed by the symbol equation (NaCl(s) → Na⁺(aq) + Cl^-(aq)) representing the process, ie information about entropy, enthalpy changes, etc.

Highlight areas of uncertainty through appropriate questioning. Push students out of their comfort zones and encourage them to engage in sense-making. In doing so, you may confront their uncertainties. Support them in identifying the limitations of models and the aspects they find most challenging.

In their work, the researchers focus on precipitation, using animations from the VisChem Institute. The SMK includes the orientations of solvating water molecules and the rapid ion-pair formation of a lattice. Relevant PCK includes: playing an animation; knowing which parts to highlight to visualise particle behaviour; and strategies for eliciting students’ ideas and observations.

In their work, the researchers focus on precipitation using animations from the VisChem Institute (bit.ly/36c7snW). The SMK includes the orientations of solvating water molecules and the rapid ion-pair formation of a lattice. Relevant PCK includes: playing an animation; knowing which parts to highlight to visualise particle behaviour; and strategies for eliciting students’ ideas and observations.

The researchers also concentrate on the use of Johnstone’s triangle, which describes the relationships between the macroscopic, particulate and symbolic levels of chemistry. Sense-making occurs when students consider the limitations of each level. The researchers stress that teachers should incentivise students to evaluate the transitions between the levels of Johnstone’s triangle.

Teaching tips

To prompt students to think about their own understanding of concepts, use Vischem’s Introduction video (bit.ly/3J7TY9W) or this video about a learning design for a redox reaction (bit.ly/37eFMPb). You could share clips from the videos in a lesson.

The dissolution of sodium chloride in water is a simple context that illustrates the researchers’ recommended teaching practices. However, you could also adapt the approach for any example where a particulate-level animation is used.

Ask students to observe the phenomenon, ie sodium chloride dissolving in water in a beaker. Use a thermometer to demonstrate that the process is endothermic – the temperature of the solution formed is slightly cooler than the initial temperature of the water. Then ask students to share ideas about the reasons for this.
Ask students what (aq) means in terms of the number of solvating water molecules and how they are oriented around the ions. The reasons for the particles’ orientations could be discussed in more detail, ie the polarity of water molecules and the charges of the ions.
Ask students to consider what information is not conveyed by the symbol equation (NaCl_(s) → Na⁺_(aq) + Cl^-_(aq)) representing the process, ie information about entropy, enthalpy changes, etc.

David Read