kelvin

(noun)

in the International System of Units, the base unit of thermodynamic temperature; 1/273.16 of the thermodynamic temperature of the triple point of water; symbolized as K

Related Terms

Examples of kelvin in the following topics:

  • Kelvin Scale

    • The kelvin is a unit of measurement for temperature; the null point of the Kelvin scale is absolute zero, the lowest possible temperature.
    • The kelvin is a unit of measurement for temperature.
    • The choice of absolute zero as null point for the Kelvin scale is logical.
    • The Kelvin scale is named after Glasgow University engineer and physicist William Thomson, 1st Baron Kelvin (1824-1907), who wrote of the need for an "absolute thermometric scale. " Unlike the degree Fahrenheit and the degree Celsius, the kelvin is not referred to or typeset as a degree.
    • To convert kelvin to degrees Celsius, we use the following formula:

  • Absolute Temperature

    • By using the absolute temperature scale (Kelvin system), which is the most commonly used thermodynamic temperature, we have shown that the average translational kinetic energy (KE) of a particle in a gas has a simple relationship to the temperature:
    • The kelvin (or "absolute temperature") is the standard thermodyanmic temperature unit.
    • By international agreement, the unit kelvin and its scale are defined by two points: absolute zero and the triple point of Vienna Standard Mean Ocean Water (water with a specified blend of hydrogen and oxygen isotopes).

  • Absolute Zero

    • The zero point of a thermodynamic temperature scale, such as the Kelvin scale, is set at absolute zero.
    • By international agreement, absolute zero is defined as 0K on the Kelvin scale and as -273.15° on the Celsius scale (equivalent to -459.67° on the Fahrenheit scale).
    • The lowest temperature that has been achieved in the laboratory is in the 100 pK range, where pK (pico-Kelvin) is equivalent to 10-12 K.

  • Celsius Scale

    • This definition also precisely relates the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature and which uses the symbol K.
    • Based on this, the relationship between degree Celsius and Kelvin is as follows:

  • Kelvin-Helmholtzor Shearing Instability

    • It turns out that even if the velocity changes gradually with position, the flow is unstable, so we would like to get a heuristic understanding of the Kelvin-Helmholtz instability.

  • The Third Law

    • At zero kelvin the system must be in a state with the minimum possible energy, thus this statement of the third law holds true if the perfect crystal has only one minimum energy state.
    • Entropy is related to the number of possible microstates, and with only one microstate available at zero kelvin the entropy is exactly zero.

  • Blackbody Radiation

    • For one thing it has units of Kelvin rather than something clumsy.

  • Thermodynamics

    • The brightness temperature has several nice properties.For one thing it has units of Kelvin rather than something clumsy.Second if a material is emitting thermal radiation one can obtain a simple expression of the radiative transfer equation (see the problems).

  • Blackbody Temperatures

    • The brightness temperature has several nice properties.For one thing it has units of Kelvin rather than something clumsy.

  • Converting Units

    • An example is the conversion between degrees Celsius and kelvins, or between Celsius and Fahrenheit.