How this calculator works
UNESCO EOS-80 combines a fresh-water polynomial with salinity terms and a pressure-dependent secant bulk modulus. This tool accepts 0 to 40 C, Practical Salinity 0 to 42, and sea pressures up to 100 MPa above one atmosphere. Temperature is treated on the historical IPTS-68 scale used by EOS-80. The mass method approximates Practical Salinity by salt mass fraction in g/kg; it is not an accurate equation of state for arbitrary salt solutions. Compare measured object density rather than assuming every egg or fruit has one value.
Formula
rho(S,t,p) = rho(S,t,0)/[1-p/K(S,t,p)], with sea pressure p in bar. Approximate salinity = 1000 m_salt/(m_salt+m_water). Floating submerged fraction = rho_object/rho_water.
Worked example
At salinity 35, temperature 0 C and one atmosphere, EOS-80 gives 1028.106331 kg/m3. At 30 C under the same pressure it gives about 1021.728639 kg/m3.
Advertisement
Frequently asked questions
Is pressure gauge or absolute?
Enter absolute pressure. The tool subtracts 101325 Pa before applying the sea-pressure correction.
Can I use hot water?
This EOS-80 implementation is restricted to 0 through 40 C. The viscosity tool covers saturated pure water to 100 C.
Will an egg float?
Compare its measured bulk density with the calculated liquid density. Natural objects vary, so their names do not supply reliable constants.