File talk:Melting curve of water.jpg

pressure lowers freezing point of water a slight amount

 * www1.lsbu.ac.uk/water/density_anomalies.html Explanation of the Density Anomalies of Water
 * "Pressure reduces ice's melting point (13.35 MPa gives a melting point of -1 °C)"
 * "In water, this line is backward sloping with slope 13.46 MPa ˣ K-1 at 0 °C, 101.325 kPa."

Many people want to know if the pressure in water pipes lowers the freezing point. Almost all Internet info including WP is not helpful: science phase diagrams in unfamiliar units that do not show appropriate detail, only that the melt temp does not vary much with pressure under common water pipe conditions.

It would be great to have a graph of temp in C and F (not K) vs pressure in PSI for 0-10,000 PSI for inclusion in WP articles. Until then, 13.35 MPa converts to 1936.25 psi (pounds per sq. inch). We could say something like:


 * Pressure in water pipes reduces the freezing point slightly: a pressure of 1936 psi lowers the freezing point to -1 °C.

The graph in the good Martin Chaplin LSBU article appears to show that 100 MPa (14,500 psi) would lower the melt temp by about 10 °C.

Typical water pipe pressures are usually around 100 psi, which apparently would lower the freezing point by a small fraction of a degree. If the slope at zero is 13.46 MPa per degC, that works out to 0.051 °C (0.092 °F) for 100 psi. It would be a relevant factoid to include in some articles, if we could be sure of the science/physics facts.-73.61.15.87 (talk) 20:13, 11 January 2018 (UTC)