The functional principle of a rotating-shaft pointer can be easily demonstrated in a simple experiment and studied by the students.
Principle
Metal tubes are heated with steam. The linear expansion of three different metals is determined with the aid of a rotating-shaft pointer. From this the metals’ coefficient of linear expansion is determined (Supplementary problem). The use of a rolling-shaft pointer is advantageous because the resulting indication of expansion is frictionless. The functional principle of a rotating-shaft pointer can be easily demonstrated in a simple experiment and studied by the students. The students should do this before they calculate the change in length Δl in “Evaluation”.
Benefits

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