Search results
Results from the WOW.Com Content Network
Notably, the Kelvin, Celsius, Rankine, and Fahrenheit scales were, or currently are, defined by the freezing and boiling points of water. The less common scales of Delisle, Newton, Réaumur, and Rømer were defined similarly. The triple point of water is a more commonly used standard point today.
Freezing point (°C) K f (°C⋅kg/mol) ... Water: 100.00 0.512 0.00 ... Freezing-point depression; Boiling-point elevation; References
Water boiling at 99.3 °C (210.8 °F) at 215 m (705 ft) elevation. The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid [1] [2] and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure.
For instance, precise measurements show that the boiling point of VSMOW water under one standard atmosphere of pressure is actually 373.1339 K (99.9839 °C) when adhering strictly to the two-point definition of thermodynamic temperature. When calibrated to ITS–90, where one must interpolate between the defining points of gallium and indium ...
Boiling is the method of cooking food in boiling water or other water-based liquids such as stock or milk. [13] Simmering is gentle boiling, while in poaching the cooking liquid moves but scarcely bubbles. [14] The boiling point of water is typically considered to be 100 °C (212 °F; 373 K), especially at sea level.
In 1738, Josias Weitbrecht (1702–47) recalibrated the Delisle thermometer with two fixed points, keeping 0 degrees as the boiling point and adding 150 degrees as the freezing point of water. He then sent this calibrated thermometer to various scholars, including Anders Celsius . [ 1 ]
[1]: 362 The boiling point of water was defined as 60 degrees. Rømer then saw that the freezing point of pure water was roughly one eighth of the way (about 7.5 degrees) between these two points, so he redefined the lower fixed point to be the freezing point of water at precisely 7.5 degrees.
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.