Use these research-informed tips to better uncover your classes’ core chemical thinking

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Look beyond right or wrong answers and put your students’ chemical thinking under the lens with formative assessment

Researchers recently studied how chemistry teachers use formative assessment. The research team, at the University of Massachusetts, US, found a variety of approaches, and that not all teachers used formative assessment to its full potential. The researchers reported how they classified the approaches. Their findings and classification method could be useful for other teachers to assess and develop their own practice.

Formative assessment allows teachers to provide feedback during or after an activity that enhances student outcomes. Previous work has shown that novice teachers tend to focus on the correctness of students’ answers rather than uncovering their underlying thinking, which is key to effective formative assessment.

Researchers Timothy Abell and Hannah Sevian tested these previous findings in a chemistry-specific context. They studied 13 chemistry teachers during their year-long professional development programme in Massachusetts. The teachers taught in different types of schools and each had between 3–14 years of classroom experience.

Formative assessment assessed

The development programme aimed to shift teachers from using assessments designed to differentiate students’ abilities towards examples that elicit and promote chemical thinking. Each teacher compiled a formative assessment portfolio during their training. The portfolios included tasks – with explanations of their purpose and expectations for good answers – and examples of evaluated students’ work. The teachers also reflected on what worked and noted their plan for the following lesson.

The researchers analysed the portfolios using the chemical thinking framework. This framework helps chemistry to be taught as a way of thinking rather than a collection of topics to be learned. The central questions of the framework explore how and why chemical processes occur, and how we identify substances and predict properties.

Developing thinking

The analysis found differences in the design, purpose and evaluation of student work. A number of teachers designed activities that could elicit students’ chemical thinking. Others developed tasks that had the potential to do this, but used questions that constrained thinking or students’ sharing of their thinking. The remaining teachers designed activities that only allowed students to demonstrate content knowledge. The teachers tended to focus on the correctness of students’ conceptual understanding when evaluating their work, even when the activity had the power to reveal students’ chemical thinking.

From their findings, the researchers postulate that some teachers may not think that chemistry is about the application of knowledge in analysing, synthesising and transforming matter. They also think that the crosscutting concepts of the chemical thinking framework would be useful for teachers, who could use it to focus formative assessment activity on the development of students’ chemical thinking.

Teaching tips

  • Consider the design and implementation of formative assessment activities to maximise the benefits for students.
  • Enhance tool-oriented tasks by asking students to apply a tool in explaining a phenomenon. Used alone, tool-oriented tasks (eg, applying c = n/v) that only have a single correct answer obtained via an algorithmic method, do not necessarily provide insight into students’ thinking.
  • Promote chemical thinking by adding open-ended questions. For example, add the questions, ‘What happens when H+ ions are added to pure water?’ and ‘How does the solution become more acidic?’, to a task requiring students to use H+ and OH­- cards to show what happens to the number of hydrogen ions when acid is added to water. The card task alone would limit insights into how students came to their answers.
  • Ask students to draw and explain their own representations showing the changes in the arrangement of particles during a process. This may be more effective than offering students a ‘forced choice’, such as a correct particulate representation from a range of options showing what happens to molecules. The forced choice limits evaluation to known misconceptions, rather than other ideas individual students may possess.
  • Consider how a student’s thinking is changing as a result of a task, even when their answers are incorrect. Feedback can then help the student move in the right direction. Practising this skill will help you to infer students’ thought processes from relatively short written answers.