Temperature call average kinetic energy of particles of the system which is in thermodynamic balance. It follows from this that temperature has to be taken in the power units included in the SI system in Joules. But, historically it developed that temperature began to be taken long before emergence of the molecular and kinetic theory and in practice apply conventional units – degrees. In the international SI system unit of measure of thermodynamic body temperature is Calvin (K), being one of seven main units of a system. However in practice most often temperature is taken in degrees Celsius.
Instruction
1. On Calvin's scale the counting of temperature is conducted from absolute zero – a state in which completely there are no thermal fluctuations, one degree of a scale is equal 1/273.15 distances from absolute zero to a threefold point of water. The threefold point of water is a state in which ice, water and water vapor are in balance. The concept of absolute temperature was entered by U. Thomson (Calvin) therefore this scale is called on his name.
2. As a part of the derivative sizes SI degrees Celsius are applied to measurement of temperature. The scale of Celsius was offered in 1742 by the Swedish scientist A. Tselsy and is often put into practice. This scale is tied to the main characteristics of water – the ice thawing temperature (0 °C) and boiling temperature (100 °C). This scale is convenient because the majority of natural processes happens in this temperature range. Actually temperatures of boiling and freezing of water are determined insufficiently precisely therefore the scale of Celsius is defined through Calvin's scale. The absolute zero at the same time is defined as 0 K that equally 273.15 °C equal.
3. For the translation of body temperature from Kelvins in degrees Celsius, it is necessary to take away from kelvins 273.15, the received number will equal to the body temperature expressed in degrees Celsius. That is 1 K = With + 273.15; 1 C = To – 273.15.