Densitas

2.2  Mechanical properties of materials

2.2.1 Densities

Density of water (unit 1 kg m−3)

Pure air-free water under a pressure of 101 325 Pa.

Values based on the following expression (Kell, 1975, 97–105, recalculated for ITS-90 by Bettin and Spieweck, 1990, 195–196):

  density at t/°C = (999.839 52 + 16.952 577t − 7.990 512 7 × 10−3t2 − 46.241 757 × 10−6t3

                    + 105.846 01 × 10−9t4 − 281.030 06 × 10−12t5)/(1 + 16.887 236 × 10−3t)

A new formula with lower uncertainty is available for the temperature range 0 °C to 40 °C, see Tanaka et al., 2001, 301-309. This new formula is valid for SMOW (standard mean ocean water) and it predicts density values that are about 3 ppm higher than those given by the above formula. Taking this into account, the deviations from the above formula are less than 1 ppm.

In the range 0 to 25 °C, the correction (/kg m −3) for air-saturated water at temperature t (Bignell 1983, 57−59) is

     −(4.612 − 0.106t) × 10−3

The temperature (tm/°C) of maximum density at different pressures (p/Pa) is given by

     tm = 3.98 − 0.222 × 10−6(p − 101 325)

Information on the preparation of water as a reference material, together with the dependence of its density upon isotopic abundance can be found in Marsh (1987, 13–16).

Density of heavy water

Originally calculated by Kell (1967), from measurements by Chang and Tung (1949), Shrader and Wirtz (1951) and Steckel and Szapiro (1963).

Under a pressure of 101 325 Pa.

Density of mercury (unit 1 kg m-3)

Under a pressure of 101 325 Pa.