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The possibility of negative temperatures was first predicted by Lars Onsager in 1949. [4] Onsager was investigating 2D vortices confined within a finite area, and realized that since their positions are not independent degrees of freedom from their momenta, the resulting phase space must also be bounded by the finite area.
Materials with a negative temperature coefficient have been used in floor heating since 1971. The negative temperature coefficient avoids excessive local heating beneath carpets, bean bag chairs, mattresses, etc., which can damage wooden floors, and may infrequently cause fires.
Such negative temperatures are hotter than any positive temperature. Over time, when the subsystem is exposed to the rest of the body, which has a positive temperature, energy is transferred as heat from the negative temperature subsystem to the positive temperature system. [101] The kinetic theory temperature is not defined for such subsystems.
The Low Temperature Laboratory recorded a record low temperature of 100 pK, or 1.0 × 10 −10 K in 1999. [11] The current apparatus for achieving low temperatures has two stages. The first uses a helium dilution refrigerator to get to temperatures of millikelvins, then the next stage uses adiabatic nuclear demagnetisation to reach picokelvins ...
A system with a truly negative temperature is not colder than absolute zero. Rather, a system with a negative temperature is hotter than any system with a positive temperature, in the sense that if a negative-temperature system and a positive-temperature system come in contact, heat flows from the negative to the positive-temperature system. [11]
This is a list of countries and sovereign states by temperature. Average yearly temperature is calculated by averaging the minimum and maximum daily temperatures in the country, averaged for the years 1991 – 2020, from World Bank Group , derived from raw gridded climatologies from the Climatic Research Unit .
Highest dew point temperature: A dew point of 35 °C (95 °F) — while the temperature was 42 °C (108 °F) — was observed at Dhahran, Saudi Arabia, at 3:00 p.m. on 8 July 2003. [ 200 ] Highest heat index : In the observation above at Dhahran, Saudi Arabia, the heat index ("feels like" temperature) was 81.1 °C (178.0 °F).
Negative numbers are used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature. The laws of arithmetic for negative numbers ensure that the common-sense idea of an opposite is reflected in arithmetic. For example, − (−3) = 3 because the opposite of an opposite is the original value.