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Supercooled water, still in liquid state Start of solidification as a result of leaving the state of rest. Supercooling, [1] also known as undercooling, [2] [3] is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid.
Temperature vs time plots, showing the Mpemba Effect. The Mpemba effect is the name given to the observation that a liquid (typically water) that is initially hot can freeze faster than the same liquid which begins cold, under otherwise similar conditions.
The melting point of water at 1 atmosphere of pressure is very close to 0 °C (32 °F; 273 K), and in the presence of nucleating substances the freezing point of water is close to the melting point, but in the absence of nucleators water can supercool to −40 °C (−40 °F; 233 K) before freezing. [4] [5] Under high pressure (2,000 ...
Most liquids under increased pressure freeze at higher temperatures because the pressure helps to hold the molecules together. However, the strong hydrogen bonds in water make it different: for some pressures higher than 1 atm (0.10 MPa), water freezes at a temperature below 0 °C. Subjected to higher pressures and varying temperatures, ice can ...
One can therefore observe a delay until the water adjusts to the new, below-freezing temperature. [10] Supercooled liquid water must become ice at −48 °C (−54 °F), not just because of the extreme cold, but because the molecular structure of water changes physically to form tetrahedron shapes, with each water molecule loosely bonded to ...
During a phase transition of a given medium, certain properties of the medium change as a result of the change of external conditions, such as temperature or pressure. This can be a discontinuous change; for example, a liquid may become gas upon heating to its boiling point, resulting in an abrupt change in volume. The identification of the ...
Apply heat until full water pressure is restored. If you are unable to locate the frozen area, if the frozen area is not accessible, or if you can not thaw the pipe, call a licensed plumber ...
These conditions are considered unusual, [6] restricting it to a process of importance within a few centimeters of a rock's surface and on larger existing water-filled joints in a process called ice wedging. Not all volumetric expansion is caused by the pressure of the freezing water; it can be caused by stresses in water that remains unfrozen.