The incandescent light bulb was one of the first early applications of electricity, and it’s hard to underestimate its importance. But before the electric light, people didn’t live in darkness — they ...

Discover how ice crystals and winter skies create sundogs, sun pillars and halos — and when to look up from the Nature Center ...

IN such elementary text-books on geometrical optics as I have consulted it has always seemed to me that the writers have found a difficulty in presenting a precise direct proof of the theorem that ...

The Wordle word of the day on December 25 was prism, a word that feels almost unfairly elegant for something so relentlessly honest. A prism exists to intervene between appearance and understanding, ...

Physicists at Harvard University in the US have built a silicon waveguide that exhibits a refractive index of, or close to, zero when operating at near-infrared telecom wavelengths. The waveguide can ...

Refractometers are versatile in their design and use, and are able to provide results as refractive indices, or in other cases, as direct measurements of parameters such as soluble solids, sugar ...