Mercury
Mercury at 20 °C — 13 534 kg/m³, the density that makes a millimetre of it a usable unit of pressure.
| Phase | Liquid |
| Temperature range | Single published state at 20 °C |
| Source | CRC Handbook of Chemistry and Physics, 104th ed. |
Published at 20 °C. This fluid has no temperature curve in this library — the values below are a single measured state, not a function.
| Density | 13,534 kg/m³ |
| Dynamic viscosity | 1.526 mPa·s |
| Specific heat | 0.1395 kJ/(kg·K) |
| Thermal conductivity | 8.3 W/(m·K) |
| Kinematic viscosity ν = µ/ρ | 0.11275 mm²/s |
| Prandtl number Pr = cpµ/k | 0.02565 |
Every fluid property in these opens already filled, all from the same state — so a density and a viscosity in one calculation always describe the same fluid at the same temperature.
Hydrostatic Pressure (P = ρgh)
ρ = 13,534
Specific Gravity
ρ = 13,534
Learning zone
Mercury is 13.53 times denser than water, which is the entire reason it became the working fluid of barometers and manometers: a column of water tall enough to balance one atmosphere is 10.3 metres, and the same job in mercury takes 760 millimetres. That convenience is why mmHg, inHg and torr are still in use in vacuum work, aviation and medicine long after the instruments themselves were retired.
Its viscosity, 1.526 mPa·s, is only about 50 % higher than water's despite the enormous density difference, so the kinematic viscosity — the one that governs flow — is about 0.113 mm²/s against water's 1.004, roughly nine times LOWER. Mercury flows very freely for its weight. Thermal conductivity of 8.3 W/(m·K) is metallic, fourteen times water's, and the specific heat is tiny at 139.5 J/(kg·K).
It is a cumulative neurotoxin, absorbed through skin and inhaled as vapour at room temperature, and its instruments have been progressively banned since the 1990s. It stays in this library because the units it created are still everywhere, and because a manometer calculation still needs its density.
The constants library carries these at a single stated temperature, with their uncertainty and provenance. The table above is the same substance as a function.