an entropy measurement concept. Thus entropy values occur indirectly by processing energy measurements at defined temperatures, without producing entropy. Constant-temperature calorimeter, phase change calorimeter Heat flux sensor uses thermopiles (which are connected thermocouples) to determine current density or flux of entropy. Entropy content The given sample is cooled down to (almost) absolute zero (for example by submerging the sample in liquid helium). At absolute zero temperature any sample is assumed to contain no entropy (see Third law of thermodynamics for further information). Then the following two active calorimeter types can be used to fill the sample with entropy until the desired temperature has been reached: (see also Thermodynamic databases for pure substances) Constant-pressure calorimeter, enthalpy-meter, active Constant-temperature calorimeter, phase change calorimeter, active Entropy production Processes transferring energy from a non-thermal carrier to heat as a carrier do produce entropy (Example: mechanical/electrical friction, established by Count Rumford). Either the produced entropy or heat are measured (calorimetry) or the transferred energy of the non-thermal carrier may be measured. calorimeter (any device for measuring the work which will or would eventually be converted to heat and the ambient temperature) Entropy lowering its temperature—without losing energy—produces entropy (Example: Heat conduction in an isolated rod; "thermal friction"). calorimeter Temperature coefficient of energy or "heat capacity" Concerning a given sample, a proportionality factor relating temperature change and energy carried by heat. If the sample is a gas, then this coefficient depends significantly on being measured at constant volume or at constant pressure. (The terminology preference in the heading indicates that the classical use of heat bars it from having substance-like properties.) Constant-volume calorimeter, bomb calorimeter Constant-pressure calorimeter, enthalpy-meter Specific temperature coefficient of energy or "specific heat capacity" The temperature coefficient of energy divided by a substance-like quantity (amount of substance, mass, volume) describing the sample. Usually calculated from measurements by a division or could be measured directly using a unit amount of that sample. For the ranges of specific heat capacities see: Orders of magnitude (specific heat capacity) Coefficient of thermal expansion Dilatometer Strain gauge Melting temperature (of a solid) Differential Scanning Calorimeter gives melting point and enthalpy of fusion. Kofler bench Thiele tube Boiling temperature (of a liquid) Ebullioscope a device for measuring the boiling point of a liquid. This device is also part of a method that uses the effect of boiling point elevation for calculating the molecular mass of a solvent. See also