
The device to measure the temperature is called thermometer. All thermometers are marked with a scale using two fixed point –a lowest point at which pure ice melts and the highest point at which water boils at normal atmosphere pressure. These are called thermometer fixed points. There are three scales to measure the temperature of hot bodies. There are the look specks of light.
This thermometer is used in France to some extent. The Kelvin scale is the lowest possible thermometer theoretically achievable. It was invented by a British physician, William Thomson (1824 – 1907) who entered Glasgow University at the science of thermodynamics and established relationship between heat, work and energy. The Kelvin or the fact that it is impossible to achieve a thermometer of about -273 c in Kelvin or the thermometer (-273C) is 0, and called absolute zero. The freezing point of water, (i.e. 0c) is 273.15 Kelvin’s.
Fahrenheit and Celsius are related to each other by the equation –
F=(9C-160)/5