/oss/taxonomy/term/2107/all en /oss/article/environment-general-science-you-asked/why-sky-blue-or-better-yet-why-ocean-blue <p>The sky is blue due to a phenomenon called <a href="https://en.wikipedia.org/wiki/Rayleigh_scattering">Raleigh scattering</a>. This scattering refers to the scattering of electromagnetic radiation (of which light is a form) by particles of a much smaller wavelength. Sunlight is scattered by the particles of the atmosphere, and what comes through down to earth is called diffuse sky radiation, and though only about 1/3rd of light is scattered, the smallest wavelengths of light tend to scatter easier.</p> Fri, 31 Jan 2020 19:08:37 +0000 Ada McVean B.Sc. 8097 at /oss /oss/article/environment-health/colourful-thoughts <p><span>I am no alarmist when it comes to "artificial chemicals" used in food or cosmetic production. But I do question the use of colourants because they have no function other than changing the appearance of a product. Why do we need mouthwash to be blue? It's because somehow people have been conditioned to associate blue with cleanliness, which is why window cleaners, toilet bowl cleaners and mouthwashes are blue.</span></p> Sat, 13 Feb 2016 01:04:34 +0000 Joe Schwarcz PhD 2316 at /oss