Water shows at least 17 phases when subjected to changes in pressure and temperature. Under ambient pressure, water undergoes the XI-I-Liquid-Vapor phase transition and density oscillation. The phase boundaries also vary with the load of a perturbation. Compression lowers the melting point Tm and raises the temperature for ice nucleation TN, according to the phase diagram. The Tm(P) drops by -22 °C under 210 MPa and rises by +6.5 °C under -95 MPa tension . In the liquid and ice-I, water follows the regular law of thermal expansion while at Liquid-Ice traction shows negative thermal expansivity .