Knowledge database: Basics: Density

Density is defined as the mass per unit volume of a particular sample. It is marked with the Greek letter ρ (rho). Density depends on several factors, such as temperature, pressure, crystal structure, etc. Solids and liquids behave relatively similar, while gas density is considerably influenced by pressure. Density usually drops when the temperature is increased. In addition, the solid state of a substance, usually has a higher density than the liquid state of the same substance. This is not true only in the case of water, in which the ice as a solid state has a lower density than liquid water. Water has a maximum density at 4 °C.

The densest element currently known is osmium. A small cube with a 1 cm edge length weighs 22.6 grams. On the other hand, one of the materials with the lowest density is aerogel. A cube of the same size, weighs about 0.001 to 0.002 grams.

The range of density values in the PTE.