K

Kelvin

K = °C + 273.15
Quick Reference
Formula / NotationK = °C + 273.15
Also Known AsK (Kelvin), absolute temperature, thermodynamic temperature unit

What is Kelvin?

The Kelvin (K) is the SI base unit of thermodynamic temperature. Unlike Celsius and Fahrenheit, the Kelvin scale is an absolute temperature scale — it starts at absolute zero (0 K = −273.15°C), the theoretical temperature at which all molecular motion ceases. Named after Lord Kelvin (William Thomson), the Kelvin scale is essential in scientific calculations, particularly in thermodynamics and gas laws.

Formula & Notation

K = °C + 273.15

Other Names / Synonyms: K (Kelvin), absolute temperature, thermodynamic temperature unit

Properties & Characteristics

Absolute zero: 0 K = −273.15°C = −459.67°F. Conversion: K = °C + 273.15. Triple point of water: 273.16 K (0.01°C). Boiling point of water: 373.15 K (100°C). Room temperature: ~298 K (25°C). No negative temperatures in Kelvin (below 0 K impossible). Symbol: K (no degree symbol). SI base unit.

Uses & Applications

Thermodynamic calculations (ideal gas law PV = nRT requires T in Kelvin). Chemical equilibrium constants (temperature dependence). Spectroscopy (Planck equation, Wien's law). Cryogenics (liquid He: 4.2 K, liquid N₂: 77 K). Astronomy (stellar temperatures). Boltzmann equation (k_B T). Blackbody radiation.

Safety Information

Temperature unit — no direct safety concerns. Very low Kelvin temperatures (cryogenic range) involve liquid gases with associated hazards.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Kelvin
Formula K = °C + 273.15
Synonyms K (Kelvin), absolute temperature, thermodynamic temperature unit

Frequently Asked Questions

The Kelvin (K) is the SI base unit of thermodynamic temperature. Unlike Celsius and Fahrenheit, the Kelvin scale is an absolute temperature scale — it starts at absolute zero (0 K = −273.15°C), the theoretical temperature at which all molecular motion ceases. Named after Lord Kelvin (William Thomson), the Kelvin scale is essential in scientific calculations, particularly in thermodynamics and gas laws.

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