We construct a thermometer exploiting the electric resistance of the filament of a small lamp used in micro-illumination settings. The instrument may guarantee a response time better than 10 ms, i.e. much faster than commercial thermocouples or other quite expensive devices. This makes our thermometer a useful one in several processes which are…

We discuss three methods of measuring the density of air most commonly used in a teaching context. Emphasis is put on the advantages and/or difficulties of each method. In particular, we show that the 'rubber balloon' method can still be performed with meaningful physical insight, but it requires a very careful approach. (Contains 4 figures and 3…

A simple experiment is presented to visualize inferior and superior mirages in the laboratory. A quantitative analysis is done using ray tracing with both photographic and computational techniques. The mirage's image, as seen by the eye or the camera lens, can be used to analyse the deflection and inversion of light rays. (Contains 6 footnotes, 1…