Candling

thumb|Candling an egg

Candling is a method used in embryology to study the growth and development of an embryo inside an egg. The method uses a bright light source behind the egg to show details through the shell, and is so called because the original sources of light used were candles. thumb|A tool used in the 19th century to hold eggs in front of a light source. The technique of using light to examine eggs is used in the egg industry to assess the quality of edible eggs.