Kelvin

The kelvin is the SI base unit of thermodynamic temperature. Its size is defined by fixing the Boltzmann constant at exactly 1.380649 × 10⁻²³ joules per kelvin.

Thermodynamic temperature: A temperature measure defined through the laws of thermodynamics and statistical mechanics. Kelvin measures this physical quantity rather than temperature as a particular instrument reading.
Statistical mechanics: The framework that derives macroscopic thermodynamic behavior from the statistics of microscopic states. It explains how temperature relates to the energy distribution of particles.
William Thomson, 1st Baron Kelvin: A Scottish physicist and engineer who formulated an absolute thermodynamic temperature scale. The unit's name honors his work on absolute temperature.
Black-body radiation: Electromagnetic radiation emitted by an ideal absorber whose spectrum depends on its temperature. Its spectrum provides a route to determining high temperatures in kelvins.
Boltzmann constant: A physical constant relating thermal energy to temperature at the scale of individual particles. Fixing its numerical value defines the kelvin in the modern SI.
Thermal energy: Energy associated with the random microscopic motion and interactions of particles in matter. The Boltzmann constant expresses a characteristic thermal energy per kelvin.
Celsius scale: A temperature scale historically based on water's freezing and boiling points, now defined through the kelvin. Its familiar degree scale differs from kelvin chiefly by an offset.
Cryogenics: The science and technology of producing and studying very low temperatures. Kelvin quantifies the temperatures at which cryogenic materials and systems operate.
International System of Units: The internationally agreed system of measurement units and their definitions. The kelvin is one of its seven base units.
Temperature measurement: The determination of temperature using calibrated instruments or physical measurement methods. Practical realizations translate the kelvin definition into measurable quantities.

Linked from 17 pages