Thermodynamics

Thermodynamics

Temperature-related considerations dominate thermodynamics. There are two distinct thermal properties: A thermal potential — the temperature. For example: A glowing coal has a different thermal quality than a non-glowing one.

And a substance-like property, — the entropy; for example: One glowing coal won't heat a pot of water, but a hundred will.

Energy in thermodynamics is calculated by multipying the thermal potential by the amount of entropy found at that potential: temperature times entropy.

Entropy can be created by friction but not annihilated.

Thermodynamics(or mole number)

A physical quantity introduced in chemistry; usually determined indirectly. If mass and substance type of the sample are known, then atomic- or molecular masses (taken from a periodic table, masses measured by mass spectrometry) give direct access to the value of the amount of substance. See also the article about molar masses. If specific molar values are given, then the amount of substance of a given sample may be determined by measuring volume, mass or concentration. See also the subsection below about the measurement of the boiling point.

• Gas collecting tube gases

Temperature

• Electromagnetic spectroscopy

• Galileo thermometer

• Gas thermometer principle: relation between temperature and volume or pressure of a gas (Gas laws).

• constant pressure gas thermometer

• constant volume gas thermometer

• Liquid crystal thermometer

• liquid thermometer principle: relation between temperature and volume of a liquid (Coefficient of thermal expansion).

• Alcohol thermometer

• Mercury-in-glass thermometer

• Pyranometer principle: solar radiation flux density relates to surface temperature (Stefan–Boltzmann law)

• Pyrometers principle: temperature dependence of spectral intensity of light (Planck's law), i.e. the color of the light relates to the temperature of its source, range: from about −50 °C to +4000 °C, note: measurement of thermal radiation (instead of thermal conduction, or thermal convection) means: no physical contact becomes necessary in temperature measurement (pyrometry). Also note: thermal space resolution (images) found in Thermography.

• Resistance thermometer principle: relation between temperature and electrical resistance of metals (platinum) (Electrical resistance), range: 10 to 1,000 kelvins, application in physics and industry

• solid thermometer principle: relation between temperature and length of a solid (Coefficient of thermal expansion).

• Bi-metallic strip

• Thermistors principle: relation between temperature and electrical resistance of ceramics or polymers, range: from about 0.01 to 2,000 kelvins (−273.14 to 1,700 °C)

• Thermocouples principle: relation between temperature and voltage of metal junctions (Seebeck effect), range: from about −200 °C to +1350 °C

• Thermometer

• Thermopile is a set of connected thermocouples

• Triple Point cell used for calibrating thermometers.

• Thermographic camera uses a microbolometer for detection of heat-radiation.

Imaging technology

See also Temperature measurement and Category:Thermometers. More technically related may be seen thermal analysis methods in materials science.

For the ranges of temperature-values see: Orders of magnitude (temperature)

Energy carried by entropy or thermal energy

Actinometer measures the heating power of radiation.This includes thermal capacitance or temperature coefficient of energy, reaction energy, heat flow ... Calorimeters are called passive if gauged to measure emerging energy carried by entropy, for example from chemical reactions. Calorimeters are called active or heated if they heat the sample, or reformulated: if they are gauged to fill the sample with a defined amount of entropy.

• constant-temperature calorimeter, phase change calorimeter for example an ice calorimeter or any other calorimeter observing a phase change or using a gauged phase change for heat measurement.

• constant-volume calorimeter, also called bomb calorimeter

• constant-pressure calorimeter, enthalpy-meter or coffee cup calorimeter

• Differential Scanning Calorimeter

• Reaction calorimeter