حرارت سنج جیوه ای در قرن هیجدهم میلادی توسط "گابریل دانیل فارنهایت"که فیزیک دانی آلمانی بود اختراع گردید.

او درجه حرارت بدن انسان را 100درجه در مقیاس خود در نظر گرفت( که بعدها دریافت که در عمل این رقم98/6درجه است که آنهم به دلیل خطا در تعیین نقاط ثابت بوده است).و درجه حرارت سردترین چیزی که میتوانست در آزمایشگاه خود به آن دست یابند(که عبارت بود از مخلوطی از نمک و یخ)برابر بود با عدد صفر درجه.

نقطه انجماد و نقطه جوش آب خالص در سطح دریا میبایست به ترتیب 32درجه و 212 درجه باشد.

هر چند حرارت سنج تکامل یافته بود، و مقیاس فارنهایت بلا تغییر باقی ماند بعضا ترجیح داده میشود از مقیاس سلسیوس که در سال 1742 توسط"آندرس سلسیوس"، ستاره شناس سوئدی ابداع گردید،و تقسیم بندی جزیی تری دارد استفاده گردد.

جهت اندازه گیری بسیار دقیق درجه حرارت، دانشمند دیگری بنام "لرد کلوین"(با نام واقعی ویلیام تامسون) برای نخستین بار پیشنهاد بکارگیری حرارت سنج گازی را در قرن نوزدهم مطرح ساخت.درجه حرارت صفر مطلق برابر است با (-273) درجه در مقیاس سلسیوس ، که در این درجه هرگونه فعالیت اتمی متوقف می گردد.

The German instrument maker Gabriel Daniel Fahrenheit (1686-1736) made the first reliable thermometers. The temperature scale he originated is named after him.

Born in Danzig on May 14, 1686, Gabriel Fahrenheit was the son of a well-to-do merchant. He lost both parents on the same day, Aug. 14, 1701, and was thereafter apprenticed to a shopkeeper in Amsterdam. After completing a term of 4 years there, he turned to physics and became an instrument maker and glassblower. Although he lived in Amsterdam most of his life, he traveled widely and spent considerable time in England, where he became a member of the Royal Society.

Fahrenheit completed his first two thermometers by 1714. They contained alcohol and agreed exactly in readings. The scale which was to bear Fahrenheit"s name had not yet been calibrated, and many different scales were tried before he settled on one. He soon decided to replace the alcohol with mercury and completed a series of investigations based on the work of G. Amontons, in which he determined the boiling point of water and other liquids and studied the expansion properties of mercury. These experiments led to the discovery that the boiling point of water varied with changes in atmospheric pressure. Fahrenheit also discovered the phenomenon of supercooling of water, that is, cooling water to below its normal freezing point without converting it to ice.

Taking all of these factors into consideration, Fahrenheit was led to doubt the reliability of the freezing and boiling points of water and finally settled on a temperature scale ranging from 0 to 212. In 1724, announcing his method of making thermometers in the Philosophical Transactions of the Royal Society, he wrote concerning his scale, " ... degree 48, which in my thermometers holds the middle place between the limit of the most intense cold obtainable artificially in a mixture of water, of ice, and of sal ammoniac or even of sea salt, and the limit of heat which is found in the blood of a healthy man." (It has been suggested that the 96-degree range was chosen simply for the convenience of that number when laying off the scale by halving spaces on the thermometer stem.) Thus, finding the temperatures of the human body and of his freezing mixture to be reliable parameters, he set 0 as the temperature of the mixture; 32 as the temperature of water and ice; and 212, a point selected by chance, as about the boiling point of water.

Fahrenheit"s thermometers were highly esteemed. He used mercury successfully because of his technique for cleaning it, and he introduced the use of cylindrical bulbs instead of spherical ones. However, his detailed technique for making thermometers was not disclosed for some 18 years, since it was a trade secret. Among the other instruments which he devised were a constant-weight hydrometer of excellent design and a "thermobarometer" for estimating barometric pressure by determining the boiling point of water.

On Sept. 16, 1736, Fahrenheit died, unmarried, in the Netherlands, presumably in The Hague, where he was buried.

Source:http://www.bookrags.com/biography/gabriel-daniel-fahrenheit/

Anders Celsius
(1701-1744)

Swedish astronomer, physicist and mathematician who is famous for the temperature scale he developed. Celsius was born in Uppsala where he succeeded his father as professor of astronomy in 1730. It was there also that he built Sweden"s first observatory in 1741.

Celsius" fixed scale for measuring temperature defines zero degrees as the temperature at which water freezes, and 100 degrees as the temperature at which water boils. This scale, an inverted form of Celsius" original design, was adopted as the standard and is still used in almost all scientific work.

Source:http://www.energyquest.ca.gov/scientists/celsius.html

JOIN THE KELVIN CONSCIOUSNESS MOVEMENT TODAY!

The Lord Kelvin delivers a sermon from His Lecture Hall.

LORD KELVIN:
Giver of Laws

The Lord Kelvin, in His infinite wisdom, has given the Universe Laws by which to govern itself THERMODYNAMICALLY:—

The Laws of Thermodynamics

Law The Zeroth:

Two systems in Thermal Equilibrium with a third are in Thermal Equilibrium with each other

The property that characterizes Thermal Equilibrium is Temperature. The Lord Kelvin tells us that there is an ABSOLUTE Temperature! Since bodies that are in contact with each other will eventually reach Thermal Equilibrium, it follows that by being in contact with the Lord Kelvin we may come to be one with Him.

Law The First:

Energy Is Conserved

The Lord Kelvin, in His infinite benevolence, has deigned that the total Energy Content of the Universe shall remain constant; never being Created nor Destroyed, but only Transformed from one form to another.

Law The Second:

Universal Entropy Increases

Over the Universe as a whole, Entropy will increase. Entropy is that Energy that no longer is Ordered. It is Death of the most Absolute kind! All is susceptible to its Chilly Grasp: plants, animals, information, even The Human Soul! Sure, all those things, even our Souls, will have time until that happens; until the Universal Entropy consumes everything in the Great Heat Death, but THEN what? What will you do?

Law The Third:

A Pure Crystal"s Entropy Is Zero At Zero Kelvins

The Purest Crystal of them all is The Lord Kelvin himself! The Lord Kelvin is without Entropy. Furthermore, since Absolute Zero is unattainable via a finite series of processes, it follows that the Lord Kelvin is Infinite! This implies that His powers are also Infinite, meaning that the Lord Kelvin can transcend His own Law The Second and Conserve you from Entropy!

....

Absolute Temperature

From Law The Zeroth we see that the Lord Kelvin tells us that there IS an ABSOLUTE Temperature! Don"t listen to the lies of the Thermic Relativists; the TRUTH of the Absolute Nature of Temperature will warm your Mind & Heart and fulfill you as nothing they will ever spew could.

Because the Lord Kelvin gave us the gift of the Knowledge of the Absolute Temperature, we honor His wisdom and the beauty of His creation by measuring Temperature in Kelvins. Do not use the hurtful and deceitful Celsius and Fahrenheit scales! They are the tools of Relativists and other sad, twisted haters of the Lord Kelvin. And remember: never say "degrees Kelvin", just say "Kelvins", as in "273.16 Kelvins". Every time you do, you bring a smile to His face.

Source:  http://zapatopi.net/kelvin/

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