The Newton scale is a

temperature scale Scale of temperature is a methodology of calibrating the physical quantity temperature in metrology. Empirical scales measure temperature in relation to convenient and stable parameters or reference points, such as the freezing and boiling point ...

devised by

Isaac Newton Sir Isaac Newton () was an English polymath active as a mathematician, physicist, astronomer, alchemist, theologian, and author. Newton was a key figure in the Scientific Revolution and the Age of Enlightenment, Enlightenment that followed ...

in 1701. He called his device a "

thermometer A thermometer is a device that measures temperature (the hotness or coldness of an object) or temperature gradient (the rates of change of temperature in space). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb ...

", but he did not use the term "temperature", speaking of "degrees of heat" () instead. Newton's publication represents the first attempt to introduce an objective way of measuring (what would come to be called) temperature (alongside the Rømer scale published at nearly the same time). With Newton using melting points of various alloys such as

bismuth Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

and tin, he was the first to employ melting or freezing points of metals for a temperature scale. He also contemplated the idea of

absolute zero Absolute zero is the lowest possible temperature, a state at which a system's internal energy, and in ideal cases entropy, reach their minimum values. The absolute zero is defined as 0 K on the Kelvin scale, equivalent to −273.15 ° ...

. Newton likely developed his scale for practical use rather than for a theoretical interest in thermodynamics; he had been appointed Warden of the Mint in 1695, and

Master of the Mint Master of the Mint is a title within the Royal Mint given to the most senior person responsible for its operation. It was an office in the governments of Scotland and England, and later Great Britain and then the United Kingdom, between the 16th ...

in 1699, and his interest in the melting points of metals was likely inspired by his duties in connection with the

Royal Mint The Royal Mint is the United Kingdom's official maker of British coins. It is currently located in Llantrisant, Wales, where it moved in 1968. Operating under the legal name The Royal Mint Limited, it is a limited company that is wholly ow ...

. Newton used

linseed oil Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colorless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by pressing, sometimes followed by ...

as thermometric material and measured its change of volume against his reference points. He set as 0 on his scale "the heat of air in winter at which water begins to freeze" (), reminiscent of the standard of the modern

Celsius scale The degree Celsius is the unit of temperature on the Celsius temperature scale "Celsius temperature scale, also called centigrade temperature scale, scale based on 0 ° for the melting point of water and 100 ° for the boiling point ...

(i.e. 0 °N = 0 °C), but he has no single second reference point; he does give the "heat at which water begins to boil" as 33, but this is not a defining reference; the values for body temperature and the freezing and boiling point of water suggest a conversion factor between the Newton and the Celsius scale of between about 3.08 (12 °N = 37 °C) and 3.03 (33 °N = 100 °C) but since the objectively verifiable reference points given result in irreconcilable data (especially for high temperatures), no unambiguous "conversion" between the scales is possible. The linseed thermometer could be used up to the melting point of tin. For higher temperatures, Newton used a "sufficiently thick piece of iron" that was heated until red-hot and then exposed to the wind. On this piece of iron, samples of metals and alloys were placed, which melted and then again solidified on cooling. Newton then determined the "degrees of heat" of these samples based on the solidification times, and tied this scale to the linseed one by measuring the melting point of tin in both systems. This second system of measurement led Newton to derive his law of convective heat transfer, also known as

Newton's law of cooling In the study of heat transfer, Newton's law of cooling is a physical law which states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its environment. The law is frequentl ...

. In his publication, Newton gives 18 reference points (in addition to a range of meteorological air temperatures), which he labels by two systems, one in arithmetic progression and the other in geometric progression, as follows:

References

External links

Photo of an antique thermometer backing board c. 1758
arked in four scales; the first is Newton's. {{Portal bar, Energy Obsolete units of measurement Scales of temperature

See also

References

External links