CONVERSION OF TEMPERATURE

                                The SI unit for temperature is Kelvin, the absolute temperature, named after the engineer and physicist William Thomson, 1^st Baron Kelvin. The two most commonly used units for temperature are Degrees Celsius (°C) named after the Swedish astronomer Anders Celsius, and Degrees Fahrenheit (°F), named after the inventor of alcohol thermometer, Daniel Gabriel Fahrenheit.

                Celsius degree and Fahrenheit degree are not absolute values, which mean that they both have negative values. In converting units of °C to °F and vice versa, we must make use of a standard for reference in comparing the two values, that is, the freezing point and boiling point of water. Water freezes at 0°C and boils at 100°C. In Fahrenheit scale, freezing point of water is 32°F and boiling point is 212°F.

Thus, it takes 180 Fahrenheit degrees to cover the same range as that of 100 Celsius degrees. It means that one Fahrenheit degrees is 100/180 or 5/9 of a Celsius degree and one Celsius degree is 180/100 or 9/5 of a Fahrenheit degree.

                 To convert Celsius degree to Fahrenheit degree, two adjustments must be made;

•   Degree size adjustment
•   Zero-point adjustment

            Degree size adjustment is done by multiplying the given value with the conversion factor, that is,   9°F/5°C  or  5°C/9°F.For the zero point adjustment is done by adding 32°F after converting °C to °F or subtracting 32°F to the given Fahrenheit scale before converting to Celsius degrees.

Example 1: The normal human body temperature is 37°C. What temperature is this in Fahrenheit scale?

Solution: One Celsius degree is equal to 180/100 or 9/5 of a Fahrenheit degree. If you have 37°C, multiply that with 9/5 to get 66.6°F. You need to add 32°F to your answer  for the zero-point adjustment, thus getting 98.6°F.

Example 2: A furnace operates at 1852°F. What temperature is this in Celsius scale?

Solution: You first need to subtract 32°F from 1852°F so that the ranges you are comparing with Celsius scale are the same (starts at zero). One Fahrenheit degrees is 100°C/180°F or 5/9 of a Celsius degree.

Kelvin temperature is an absolute quantity, which means that zero Kelvin is the absence of temperature where atoms and electrons are thought to be immobile. Both Celsius and Kelvin scales have the same magnitude, which means that every Kelvin scale is equal to one Celsius degree 

. According to experimental studies done by Johann Heinrich Lambert in 1779, the approximate value for the absolute temperature is -273.15°C.