Definition

1. Noun:
   • The base unit of thermodynamic temperature in the International System of Units (SI): The kelvin is defined by fixing the numerical value of the Boltzmann constant. It is an absolute temperature scale where 0 K represents absolute zero, the point at which particles have minimal thermal motion.
   • A title referring to the British physicist William Thomson, 1st Baron Kelvin: The unit is named in honor of Lord Kelvin, who made significant contributions to thermodynamics and physics.

Usage Examples

• Noun (Unit of Temperature):
  • Water freezes at 273.15 kelvins.
  • The experiment must be conducted at a constant temperature of 300 kelvin.
• Noun (Person):
  • Kelvin formulated the second law of thermodynamics.
  • The Kelvin scale was developed by Lord Kelvin.

Advanced Usage

• "Degrees Kelvin": An older, now deprecated usage. The correct modern form is simply "kelvins" (e.g., 100 K is read as "one hundred kelvins," not "one hundred degrees Kelvin").
  • The star's surface temperature is approximately 5800 kelvins.
• In scientific contexts: The kelvin is used in equations of state, thermodynamics, and physics where an absolute temperature scale is required.
  • The ideal gas law uses temperature in kelvin.

Variants and Related Words

• Kelvin scale (n): The absolute temperature scale that uses the kelvin as its unit increment. Zero on the Kelvin scale is absolute zero.
  • The Kelvin scale is essential for scientific calculations.
• Kilokelvin (kK): A unit equal to one thousand kelvins.
  • The plasma reached a temperature of several kilokelvins.

Synonyms

• K (abbreviation): The standard symbol for the unit kelvin.
  • The melting point is 933 K.

Related Phrases and Concepts

• Absolute zero: The theoretical temperature of 0 K where all classical molecular motion ceases.
  • Scientists strive to cool matter to temperatures near absolute zero.
• Thermodynamic temperature: Temperature measured on an absolute scale (the Kelvin scale).
  • Thermodynamic temperature is a fundamental parameter in physics.

Noun

1. British physicist who invented the Kelvin scale of temperature and pioneered undersea telegraphy (1824-1907)
2. the basic unit of thermodynamic temperature adopted under the Systeme International d'Unites