Measurement of the Thermal Expansion of Pure Water in the Temperature Range 0°C-85°C

The thermal expansion of pure water having natural isotopic abundance was determined by the dilatometric method in a temperature range from 0 to 85 °C and under a pressure of 101 325 Pa. The following equation was obtained: ρ( t )/ρ max = 1 - [( t - 3,98152) 2 ( t + 396,18534) ( t + 32,28853)/609 628,6( t + 83,12333) ( t + 30,24455)] where ρ( t ) is the density of water at temperature t , which is expressed in terms of the ITS-90, and ρ max the maximum density. The density ratio which the above equation gives is estimated to have an uncertainty of approximately 1 × 10 -6 .