Temperature, Units and Conversions


Temperature and its Units:

Temperature, basically, is the amount of heat dissipated or absorbed by a body or a process. A hot body releases heat and a cold body absorbs heat, so as to stay in its thermal equilibrium. Temperature is measured  by sensing the heat radiations or kinetic energy of the particles in the body or by sensing the bulk behavior of the thermometric material. As we all know, Celsius, Kelvin and Fahrenheit are different scales of temperature, defined to standardize on the temperature of objects under varying conditions.
Temperature is an expression denoting a physical condition of matter. Yet, the idea of temperature is relative and different conflicting theories define it in different ways. The classical theory depicts heat as a form of energy associated with the activity of molecules of a substance. these minute particles of all matter are assumed to follow a continuous motion which we define as heat. Temperature is a measure of this heat.
For general use, like measuring temperature of a person, we use mercury thermometers which are calibrated in terms of Celsius or Fahrenheit. However, scientific and industrial grade measurements are generally done in terms of Kelvin. The conversion factor for these scales is as follows:

 ̊F and   ̊C:
 ̊C = (  ̊F - 32)  ÷ 1.8

K and   ̊C

K = ̊C + 273

 ̊F and K

 ̊F = ( K - 237)  X 1.8 + 32
The Rankine scale places its zero at -459.61 ̊F.

Various sensors and transducers used for temperature measurement can be studied in the following links:

  1. Bimetallic Thermometers
  2. RTD
  3. Thermocouple