We describe an example of learning with multiple representations in an A-level revision lesson on mechanics. The context of the problem involved the motion of a ball thrown upwards in air and studying how the associated physical quantities changed along its flight. Different groups of students were assigned to look at different aspects of the ball's motion using various representations: vector diagrams, free-body diagrams, verbal description, equations and graphs, drawn against time as well as against displacement. Overall, feedback from students about the lesson was positive. We further discuss the benefits of using computer simulation to support and extend student learning.

We investigate the electromagnetic induction phenomenon for a falling, oscillating and swinging magnet and a coil, with the help of a datalogger. For each situation, we discuss the salient aspects of the phenomenon, with the aid of diagrams, and relate the motion of the magnet to its mathematical and graphical representations. Using various representation modes to guide student thinking on how the variation of the magnetic flux can be used to predict the induced electromotive force should help students develop a deeper and more coherent conceptual understanding of the phenomenon.

In this paper, we examined teachers' understanding of electrical concepts such as power, current and potential difference based on how these concepts were applied to understand the relative brightness seen in bulbs of different wattage under different connections-series or parallel. From the responses of teachers to a concept question, we identified common lines of reasoning and the associated conceptual difficulties. To support the explanation of the concept question, we set up relevant circuits and made measurements of the circuits. We discuss the temperature dependence of the resistance of the light bulb which although critical for in depth understanding of the relative brightness, was often omitted in the teacher responses. Lastly, we share insights and strategies to elicit and confront students' thinking and to help them resolve, extend and apply their thinking with regard to the related electrical concepts using various light bulb activities.

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