Converting from Celsius to Rankine
Converting Celsius to Rankine is a little tricky since one is a relative scale and the other is absolute. Celsius is the most commonly used scale in the world while Rankine is primarily used in science and engineering. Rankine is an absolute scale based on the Fahrenheit scale; an increment of Fahrenheit is the same as an increment of Rankine.
To convert from Celsius to Rankine you need to follow two steps. The first is to convert Celsius to Fahrenheit by multiplying by 1.8 and then adding 32. Next, add the Rankine absolute zero offset of 459.67 to obtain the Rankine value. The last two additions can obviously combined by simply adding 491.67 rather than adding 32 and then a further 459.67.
For example, to convert a temperature of 25°C, first multiply by 1.8 giving 45 and add 32 to get a Fahrenheit value of 77°F. Now add 459.67 to this value to obtain 536.67°R.
To use the slightly quicker method, eliminating one step, we multiply by 1.8 as before to get 45 and then add 491.67 and arrive at the same value of 536.67°R.
About Celsius
Celsius is the most commonly used temperature scale in the world. The Celsius scale (known as the centigrade in some instances) is named after the Swedish astronomer Anders Celsius. It is based on the freezing and boiling points of water at standard atmospheric pressure making 0°C the freezing point and 100°C the boiling point.
The Celsius scale is normally found in weather forecasts, household temperatures and cooking in most countries with the notable exception of the United States.
About Rankine
Rankine is temperature unit normally used in thermodynamics. It is named after the Scottish engineer and physicist William John Macquorn Rankine, who is know for his work in thermodynamics. The Rankine scale is based on the Fahrenheit scale with degree increments identical but starting at absolute zero.
With the zero point at absolute zero (-459.67°F) it is easy to convert between Rankine and Fahrenheit: simply subtract 459.67.
The Rankine scale is not normally used in everyday life as it is an engineering unit particularly thermodynamics in the United States.