Definition
The kelvin is defined by fixing the value of the Boltzmann constant (k) to exactly 1.380 649 × 10−23 joules per kelvin (J·K−1). Thus, 1 kelvin corresponds to the change in thermodynamic temperature that results in a change of thermal energy of 1.380 649 × 10−23 J per particle.
Symbol and quantity
- Unit name: kelvin
- Symbol: K
- Base quantity: thermodynamic temperature
- Dimensional formula: [Θ]
Other temperature scales
Although kelvin (K) is the SI base unit, degrees Celsius (°C) is also commonly used for everyday measurements.
- Celsius scale: 0 °C = 273.15 K
- Fahrenheit scale: 32 °F = 273.15 K
- Conversion: T(°C) = T(K) − 273.15
Examples
- Freezing point of water = 273.15 K (0 °C)
- Boiling point of water = 373.15 K (100 °C)
- Room temperature ≈ 298 K (25 °C)
