The physics of temperature

Keywords: physics of temperature, heat, heat capacity

Abstract

Heat: a measure of the total kinetic energy of a body. Measured in joules (J). It depends on the mass of the body and the specific heat capacity of the body.1

Temperature: a measure of the average kinetic energy within a body. It describes the potential for heat energy to move from one body to another down a gradient from an area of high temperature to an area of lower temperature. It is measured using a temperature scale which is defined against fixed physical events such as absolute zero or the triple point of water.1

Heat capacity: the amount of heat energy necessary to be added to an entire body to increase the temperature by one degree Kelvin (J/K).2

Specific heat capacity: the amount of heat energy necessary to be added to one kilogram of a body to increase the temperature by one degree Kelvin (J/K/kg).2

Absolute zero: a hypothetical temperature at which all molecular movement stops (zero kinetic energy). This is not possible in reality.2

The ice point: this is the temperature at standard pressure (101.3 kPa) at which water exists in both a solid (ice) and a liquid form. Designated as 0 oC or 32 oF.1

The steam point (boiling point): the temperature at standard pressure (101.3 kPa) at which water exists in botha liquid and a vapour form. Designated as 100 oC or 212 oF.1

Triple point of water: the temperature at a pressure of 611 Pa (0.006 atm) at which water exists in a solid (ice), liquid and a vapour form. Designated as 0.01 oC.1

Author Biography

B M Gardner, University of the Witwatersrand

Department of Anaesthesiology, Helen Joseph Hospital, University of the Witwatersrand, South Africa

Published
2020-11-13
Section
FCA 1 Anaesthetic Refresher Course 2020