specific gravity Also known as relative density, the ratio of the density of a substance to that of a reference material at a specified temperature, usually water at 4°C. If the specific gravity (sg) of an inert substance is less than unity, it will float in water at 4°C. The sg of liquids is measurement with a hydrometer. Related category PROPERTIES OF MATTER Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |