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An accessible demonstration of Lenz’s law is offered in which the effect of the retarded sliding of a ring magnet on an inclined aluminum plate is observed. The experiment is done on the basis of comparison and includes the explanation of the effect.

We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law.We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

The anomalous thermal expansion of water in the 0 °C–4 °C range is extremely important to life on Earth, but it is normally not presented experimentally in educational settings. This paper presents a simple experiment to explore the anomalous thermal expansion of water in the 0 °C–4 °C range and the heat exchange processes in natural bodies of water in the winter and spring.

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