Fahrenheit(°F)	to	Celsius(°C)	Kelvin(K)

	Celsius(°C)	to	Fahrenheit(°F)	Kelvin(K)

	Kelvin(K)	to	Fahrenheit(°F)	Celsius(°C)

Fahrenheit

German-Dutch physicist Daniel Gabriel Fahrenheit (1686-1736) is the namesake of this temperature scale proposed in 1724. While there a many different opinions on how and why this scale was devised, Fahrenheit himself defines this scale as being based on 3 temperature points. The first point is based on the coldest temperature achieved under labratory conditions by Fahrenheit through the mixture of water, ice, and sea salt (ammonium chloride). This temperature is considered 0 degrees. The third point of reference is the freezing point of water, achieved by mixing only ice and water, and excluding sea salt. This temperature is considred 32 degrees. The third point of reference is quite literally the temperature of Fahrenheit's armpit. This point was considred 96 degrees. As you can probably guess, these measurements were not precise. Some time after his death it was decided to recalibrate the scale using 32 degrees at the freezing point of water and 212 degrees as the boiling point of water to allow for conversion between Celsius and Fahrenheit. It is for this reason that body temperature taken today is 98.6 degrees rather than the original 96 degrees.

Celsius

The celsius temperature scale, previously known as centigrade, is named after Swedish astronomer Anders Celsius (1791-1744), who developed a similar scale in 1742. It's definition was originally based on the boiling point and freezing point of water. For this scale the freezing point of water is defined as 0 degrees and the boiling point is defined as 100 degrees. However, by international agreement in 1954, it's basis was changed to absolute zero and the triple point of specially prepared water. Absolute zero is defined as the point at which no substance can become any colder and no heat energy remains. The triple point of water is defined as the temperature and pressure at which the three phases (gas, liquid, and solid) of extremely pure water can coexist in a state of thermodynamic equilibrium. In this state water can change to any of the 3 states with only infinite variations in temperature and pressure. In this scale absolute zero is -273.15 degrees and the triple point is defined as .01 degrees.

Kelvin

The Kelvin temperature scale is named after Irish born physicist and engineer William Thompson, 1st Baron Kelvin (1824-1907), who wrote about the need for an "absolute thermometric scale". The title Baron Kelvin was given to him in honor of his achievements, and the name taken from the River Kelvin, which flowed near his university in Scotland. As with the post 1954 Celsius scale, the Kelvin temperature scale is based on absolute zero and the triple point of specially prepared water. In this scale absolute zero is defined as 0K and the triple point of water as 273.16K.

Other random facts

Celsius and Kelvin are both based on equal temperature points. Each unit is of the same scale, so an increase in temperature of 1 Celcius is equal to 1 Kelvin.

The temperature scales of Fahrenheight and Celsius coincide at -40 degrees.

Absolute zero can never be reached artifically. In 2003 researchers at MIT announced a new record low temperature of 450pK (picokelvin) or 4.5×10^-10K (that's 0.00000000045K).

Kelvin is also used in the measure of the color temperature of light sources. The sun has a surface temperature of 5578K and a core temperature of approximatly 15,710,000K. Your computer's monitor might have color temperature settings defined in Kelvin units of measurement (9300K, 7500K, 6500K, 5400K or similar values).