Degree (temperature) temperature: (Measurement of temperature) "Degrees Kelvin" (K) is a former name for the SI unit of temperature on the thermodynamic (absolute) temperature scale. Since 1967 it has been known simply as the kelvin, with symbol K (without a degree symbol). Degree absolute (°A) is obsolete terminology, often referring specifically to the kelvin but sometimes the degree Rankine as well. Degree (temperature) The term degree is used in several scales of temperature. The symbol ° is usually used, followed by the initial letter of the unit, for example “°C” for degree(s) Celsius. A degree can be defined as a set change
Negative temperature energy states than in the lower ones. The system can then be characterised as having a negative temperature. A substance with a negative temperature is not colder than absolute zero, but rather it is hotter than infinite temperature. As Kittel and Kroemer (p. 462) put it, "The temperature scale from cold to hot runs: The corresponding inverse temperature scale, for the quantity "β" = 1/"kT" (where "k" is Boltzmann's constant), runs continuously from low energy to high as +∞, … , 0, …, −∞. Because it avoids the abrupt jump from +∞ to −∞, β is considered more natural than