The Fahrenheit scale, which measures temperature, was created by Daniel Gabriel Fahrenheit (1686-1736), a German-Dutch scientist, in 1724. Fahrenheit, who devoted much of his life’s work to the measurement of temperature, also invented the alcohol and mercury thermometers. On the Fahrenheit scale, the point at which frozen water melts is 32°, and the point where at which it boils is 212°. Between these two points is exactly 180°, a number easily divisible on a thermostat. Although we know with a degree of certainty what measurements Fahrenheit used to determine his scale, his process of arriving at the final scale is largely unknown.
Several stories have circulated regarding how Fahrenheit devised his scale. One is that he established 0° as the coldest temperature he could measure outdoors during the winter of 1708 to 1709 in Danzig, Germany. This measurement and Fahrenheit's own body temperature, which he measured at 100°, were the two marks on which he based the rest of his scale. Many think that either his thermometer was off or he was running a fever that day, resulting in the relatively high reading on the bodily temperature. The scale was then divided into 12 separate segments, which were later divided into eight, creating a scale of 96 separate degrees.
In another story, Fahrenheit figured 0° by taking a measurement of the point at which equal parts of salt and ice mixed together melt. He then established 96° as the blood’s temperature. Yet another story holds that Fahrenheit co-opted Ole Rømer’s scale of temperature. With this scale, 7.5° is the freezing point of water. Fahrenheit multiplied this number to get rid of the fractions, and then refigured 32° as water’s freezing point, with 64 degrees separating the body’s temperature at 96°. He then marked degrees using six lines.
Some believe that Fahrenheit was a Freemason, and because there are 32 degrees of enlightenment, he chose to use 32 as the melting temperature of water. Degrees are also used as levels with the Freemasons, hence the use of the word on the scale. However, there is no documented evidence that Fahrenheit was a Freemason.
In yet another story, it is said that Fahrenheit believed that a person would freeze to death at 0° and would die of heat stroke at 100°. This created a scale of 0° to 100° that encompassed the range of livable temperatures. Another story states that Fahrenheit recorded the melting point of water, the boiling point and a human’s body temperature, and then put the melting and boiling points exactly 180 degrees apart. One far fetched story says that Fahrenheit observed the melting point of butter as 100° and set it accordingly.
Because Fahrenheit degrees are 5/9 of a Celsius degree, it is easier to make more exact measurements without using fractions in the Fahrenheit scale. Fahrenheit continues to be used in the United States, although most other countries that use the metric system changed to Celsius in the 1960s and 1970s.
The Celsius temperature scale, which measures heat or cold, from 0 degrees Celsius for frozen water, to 100 degrees Celsius for boiling water, was invented by Anders Celsius, a Swedish Astronomer. Celsius named the scale he developed in 1742, the centigrade scale, and one may occasionally still see temperatures listed in centigrade. In 1954, however, scientists officially named the temperature scale after Anders Celsius to honor his work.
Anders Celsius’ scale differs from the modern use of Celsius. He set zero as the boiling point of water and one hundred as its freezing point. This was reversed shortly after his death to the more modern scale.
One of the advantages of the modern scale is that the calculations from 0-100 are far easier than Fahrenheit calculations. 0 degrees Celsius is equivalent to 32 degrees Fahrenheit. The boiling point of water, under one degree of atmospheric method is simply easier to calculate than the more complex Fahrenheit formula. pressure, is 100 degrees Celsius, or 212 degrees Fahrenheit. The base 100 Converting Celsius to Fahrenheit follows this basic formula F = (C x 1.8) + 32.
Today most countries use Celsius measurements, not simply for the weather, but for temperature measurements in baking and other applications. Scientists throughout the world use a combination of Celsius measurement and Kelvin measurements. Kelvin measurements are based on the fixed points of absolute zero, where nothing could be colder, and all matter solidifies, and the triple point of water, where gas, liquid and solid water are equally used. Kelvin is particularly useful for discussing extreme temperatures.
In the US, we typically use the Fahrenheit scale in daily use, but most weather channels also give the conversion to Celsius. Cookbooks made in the US usually give Celsius conversions as well, since baking would be completely thrown off by following Fahrenheit scales in a Celsius measure oven. Imagine the results of a cake baked for an hour at 325 C (625 F). Actually most ovens cannot reach that temperature, but if they could the results would be disastrous.
Kelvin, William Thomson, 1st Baron, 1824–1907, British mathematician and physicist, b. Belfast. He was professor of natural philosophy at the Univ. of Glasgow (1846–99). He is known especially for his work on heat and electricity. In thermodynamics his work of coordinating the theories of heat held by various leading scientists of his time established firmly the law of the conservation of energy as proposed by Joule. He introduced the Kelvin temperature scale, or absolute scale, of temperature. He also discovered the Thomson effect in thermoelectricity. The importance of the discoveries and improvements that he made in connection with the transmission of messages by submarine cables led to his establishment as a leading authority in this field. He invented the reflecting galvanometer and the siphon recorder, an instrument by which telegraphic messages are recorded in ink fed from a siphon.