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The 0 °C isotherm under normal conditions. The freezing level, or 0 °C (zero-degree) isotherm, represents the altitude in which the temperature is at 0 °C (the freezing point of water) in a free atmosphere (i.e. allowing reflection of the sun by snow, icing conditions, etc.).
The value of −240 °C, or "431 divisions [in Fahrenheit's thermometer] below the cold of freezing water" [18] was published by George Martine in 1740. This close approximation to the modern value of −273.15 °C [ 1 ] for the zero of the air thermometer was further improved upon in 1779 by Johann Heinrich Lambert , who observed that −270 ...
Freezing [1] or frost occurs when the air temperature falls below the freezing point of water (0 °C, 32 °F, 273 K). This is usually measured at the height of 1.2 metres above the ground surface. This is usually measured at the height of 1.2 metres above the ground surface.
The difference of temperatures between the freezing- and boiling-points of water under standard atmospheric pressure shall be called 100 degrees. (The same increment as the Celsius scale) Thomson's best estimates at the time were that the temperature of freezing water was 273.7 K and the temperature of boiling water was 373.7 K. [33]
The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval (a difference between two temperatures). From 1744 until 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere.
"Degree" in this case can refer to degree Celsius or degree Fahrenheit. When based on Celsius, 0 degrees of frost is the same as 0 °C, and any other value is simply the negative of the Celsius temperature. When based on Fahrenheit, 0 degrees of frost is equal to 32 °F. Conversion formulas: T [degrees of frost] = 32 °F − T [°F]
Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is similar to the formation of dew, except it occurs below the freezing point of water typically without crossing through a liquid state. Air always contains a certain amount of water vapor, depending on temperature.
Freezing is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. [ 1 ] [ 2 ] For most substances, the melting and freezing points are the same temperature; however, certain substances possess differing solid-liquid transition temperatures.