Â鶹´«Ã½

IN THE 1850s, glass-makers in Bohemia invented a new type of glass by adding small amounts of uranium ore. Not only was the glass a striking greenish-yellow colour, it also appeared to glow in the evening sun. It became very fashionable, and was used in all manner of glassware from jewellery to fruit bowls (see picture). What no one knew at the time was that it was radioactive, and the green glow was caused by fluorescence.

Fluorescence is an optical phenomenon that occurs when light absorbed by a material excites the molecules in it and causes them to emit…