See Also: palaeozoology(dictionary)

fluorescence (sh) and palaeozoology (iou)


fluorescence (sh)




Emission of electromagnetic radiation, usually visible light, caused by excitation of atoms in a material, which then reemit almost immediately (within about 10-8 seconds).

The initial excitation is usually caused by absorption of energy from incident radiation or particles, such as X rays or electrons. Because re-emission occurs so quickly, the fluorescence ceases as soon as the exciting source is removed, unlike phosphorescence, which persists as an afterglow. A fluorescent lightbulb is coated on the inside with a powder and contains a gas; electricity causes the gas to emit ultraviolet radiation, which then stimulates the tube coating to emit light. The pixels of a Television or computer screen fluoresce when electrons from an electron gun strike them. Fluorescence is often used to analyze molecules, and the addition of a fluorescing agent with emissions in the blue region of the spectrum to detergents causes fabrics to appear whiter in sunlight. X-ray fluorescence is used to analyze minerals.


palaeozoology (iou)



palaeozoology noun. Also *paleozoology. M19.
[from PALAEO- + ZOOLOGY.]
The branch of zoology that deals with extinct and fossil animals.
palaeozoo'logical adjective M19.
palaeozoologist noun E20.