Density

Density. When of two bodies of equal bulk, one contains more matter than the other, it is said to have greater density than that other. Since weight is proportional to mass, the same numbers may be and are used to represent specific gravity and density. Lithium is the least dense metal known, its density being 0.59 if that of water be called unity. Ordinary air may be easily compressed so as to be denser than lithium. Iridium is probably the densest substance known, its density being 22.4 times that of water. Osmium, however, is very nearly if not quite as dense. The more ordinary metals stand in the following order as regards density: Aluminium, antimony, zinc, iron (wrought), copper, bismuth, silver, lead, gold, platinum. See SPECIFIC DENSITY.