Did you think about where can be the different temperature scales are derived from? For example, if you are an Asian or European citizen, did you think about why the 0 of the Celsius temperature scale is 0 at this temperature? Or if you are an American, did you think about why I am measuring the temperature difference from the Celsius scale in the name of Fahrenheit? We intended to give some satisfactory information about temperature scales in science and engineering in this article.
What are the Temperature Scales?
Temperature scales are commonly used by human civilization and by us to define a numeric value to different temperature levels. In different applications, different kinds of temperature scales are used.
Which Types of Temperature Scales are Used?
Where the Celsius Temperature Scale is Derived?
Temperature scales are generally derived from very basic assumptions. For example, the Celsius temperature scale is derived from the boiling and freezing temperatures of pure water at 1 atm pressure. Among the people, the Celsius temperature scale is one of the most used ones. In the SI system, the Celsius temperature scale is commonly used.
Celsius temperature scale is renamed Swedish astronomer named A. Celsius(1702-1744).
Story of The Fahrenheit Temperature Scale
Another temperature scale is called as Fahrenheit temperature scale which is commonly used in the English unit system. Lots of people using the SI unit system complain about the English system which is also valid for the Fahrenheit temperature scale. Because Fahrenheit scale is also derived from the boiling and freezing temperatures of water at 1 atm pressure. But on the Fahrenheit scale, the freezing point of water is equal to 32℉ and the boiling point of water is equal to 212℉. So in general, conversion between these two temperature scales is somewhat easy.
The name of the Fahrenheit temperature scale is named after a German instrument maker G. Fahrenheit(1686-1736).
Temperature Scales for Thermodynamics in SI and US Systems
We briefly explained the two temperature scales that are used in daily life. But in scientific studies, there are different approaches to temperature scales are used. These two temperature scales are Kelvin and Rankine.
Kelvin Temperature Scale and Its Derivation
Kelvin temperature scale is used in scientific calculations and studies in SI unit systems. The lowest temperature on the Kelvin scale is absolute zero(0K). And linear temperature assignation is made to find other temperatures.
For example, 0℃ roughly equals 273K.
Rankine Temperature Scale in Scientific Studies
This temperature scale is named after William Rankine(1820-1872) and it is designated by the R symbol. The temperature conversions between different temperature scales are given below.
Temperature Conversions Between the Different Scales
Most of the time, people get confused between different temperature scales and they need to make conversions between different scales. We explained four types of temperature scales here and you can find very easy conversion rules between these temperature scales below.
- Relation between Kelvin and Celsius temperature scales;
T(K) = T(℃)+273.15
- Relation between Rankine scale and the Fahrenheit scale;
T(R) = T(℉)+459.67
- Relation between Kelvin and Rankine temperature scales;
T(R) = 1.87T(K)
Most people can confuse the conversion of temperature change inside the systems in different temperature scales. But it is very important information that ALL THE TOTAL TEMPERATURE CHANGES ARE SAME IN ALL TEMPERATURE SCALES IN US CUSTOMARY AND SI UNITS.
ΔT(K) = ΔT(℃)
ΔT(R) = ΔT(℉)
The relations, derivations, and logic of the most used temperature scales in different areas are very simple like above. If you learn all the information above about the temperature scales, you will not have any trouble when you face different temperature scales.
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