Every substance is associated to emission of electromagnetic radiation whose peaks are essentially influenced by temperature. Hot bodies (i.e., at T >700 °C) emit electromagnetic radiation in the field of visible light (incandescent light). The radiation emitted by cold bodies (i.e., at normal ambient conditions) in the visible light range is…

We have observed a nice example of chromatic dispersion due to refraction in water, in the form of color fringes bordering the black stripes that exist at the bottom of a swimming pool. Here we give a qualitative description of the phenomenon, explaining the role of the black stripes and the dispersive index of refraction of water.

The small-scale research that Yosanne Vella reports in this article was driven by concern to help pupils develop "big picture" visions of the past and to engage effectively with the idea of change as a process rather than an event. The strategy that she adopts--asking groups of students to colour in a timeline recording their judgement…