Temperature the International System of Units, it has subsequently been redefined in terms of the equivalent fixing points on the Kelvin scale, and so that a temperature increment of one degree Celsius is the same as an increment of one kelvin, though they differ by an additive offset of 273.15. The United States commonly uses the Fahrenheit scale, on which water freezes at and boils at at sea-level atmospheric pressure. Many scientific measurements use the Kelvin temperature scale (unit symbol: K), named in honor of the Scots-Irish physicist who first defined it. It is a thermodynamic or absolute temperature scale. Its
Temperature cool a system to absolute zero, all classical motion of its particles would cease and they would be at complete rest in this classical sense. Microscopically in the description of quantum mechanics, however, matter still has zero-point energy even at absolute zero, because of the uncertainty principle. Temperature is a measure of a quality of a state of a material. The quality may be regarded as a more abstract entity than any particular temperature scale that measures it, and is called "hotness" by some writers. The quality of hotness refers to the state of material only in a particular locality,