According to a common version, the German natural scientist was going to fix an important mark on his scale at the level of the normal temperature of the human body. However, his wife had a fever at that moment, which is why today 100 ° F corresponds to 37.8 ° C. We checked how believ is this legend.

The Fahrenheit scale is one of the main temperature scales, which is used in a number of countries of the world, in particular in the USA. Here's what the portal reports about the history of its appearance Newtonov.ruHelping schoolchildren in the study of physics: “In its scale, Fahrenheit used not two, but three main referee points. For zero, the temperature of freezing of the mixture of ice, water and ammonia was adopted, which, according to one version, corresponded to the temperature of the coldest winter of the winter of 1709. The second point is the temperature of freezing of water. She took a mark of 32 °. And the third point, at 100 °, was supposed to be the temperature of a healthy person. But either 300 years ago, people were more hot, or Fahrenheit measured something incorrectly.

In general, 100 ° F is the temperature of not a healthy person, but what is the patient himself. There is a version according to which Fahrenheit took the temperature of his wife beyond the standard of the temperature of a healthy person. But at that time she got sick, and it turned out what happened. ”

Similar information can also be found on resources such as 1001Fact.ru, Skio.ru, Mirokdetok, and in many other sources. But on the website of the Canadian State Scientific Research University Leukhead Approvedthat the researcher’s wife was healthy and, accordingly, the measurement showed 96 ° on his new scale. The portal claims the same sizes.com.

If you use it Online calculator To transfer the degrees of Fahrenheit into more familiar degrees Celsius, we will get the following result:

100 ° F = 37.777 ... ° C

That is, indeed, if a version with body temperature as a motive is true, then a not quite healthy person should serve as a standard for Fahrenheit. But let's get acquainted with the history of his invention in more detail.

Daniel Gabriel Fahrenheit was born in 1686 in Danzig (current Gdansk) in a German family. From a young age, he showed interest in natural science experiments, and later, when he had already settled in the Netherlands, he made a thermometer and a barometer. At first the thermoscopic liquid was alcohol, but around 1714 he Replaced Alcohol with mercury, which has reached much greater accuracy of measurements. Finally, in 1724, he proposed a fundamentally new scale, which will become the standard in English -speaking countries for meteorological, industrial and medical purposes for the next two and a half centuries. The following formulas are used to transfer temperature on this scale in Celsius and vice versa:

Many people who first encounter them complain about the inconvenience of such a transformation. However, few of these people know that the Celsius scale was proposed 18 years later, in 1742, that is, questions in this case should not be addressed to Fahrenheit.

So, what do we know today about the three calibration points of the Fahrenheit scale?

Thinking about a suitable markup for his future thermometer, Fahrenheit in 1708 I visited The elderly Danish astronomer is Ole Romer (not to be confused with Reomuur), who developed his own scale. It should be noted that in Romer the boiling temperature of water was 60 degrees, the temperature of a very cold winter in Denmark was taken for zero, the water froze at 7.5 degrees, and the normal body temperature was 22.5 degrees. Many years later, in a letter to another physicist Fahrenheit tell About this my visit: “I found him [Romer] in the early morning, he placed thermometers in the water with ice. He later placed them in water with body temperature. After he noted these two points on all thermometers, he added half the distance between the points below the point with the ice and divided the resulting segment by 22.5 equal part, starting from zero. 7.5 degrees - at a point with ice and 22.5 at body temperature. I used this graduation until 1717 with the only difference being that each degree divided into four more parts. <...> This graduation is very inconvenient because of the fractions, so I decided to change the scale and use 96 instead of 22.5 or 90, since then I have been using it. ”

Thus, as we see, Fahrenheit took over Ole Rummer’s development at the base of his scale, but for convenience he multiplied some (but not all, as we will be convinced) by 4. At the same time, a certain “body temperature” is mentioned in the description of the Danish scale. However, this does not give an exact answer to the question about calibration points. In his Publications of 1724 Fahrenheit writes that three of them are used in its scale: the lowest temperature of the mixture of ice, water and ammonia or even sea salt ”(0 ° F), the temperature of ice melting (32 ° F) and body temperature (96 ° F). However, this is not a completely correct message. How Mark Modern scientists, in the first case, can be obtained +5 ° F or even –8 ° F (in the case of sea salt), that is, this is not even the same value, not to mention non -compliance with zero. Perhaps right legend The fact that zero took the position of the column in an abnormally cold winter of 1708-1709 in Danzig (and not in Denmark).

In addition, after the death of Fahrenheit, his scale changed slightly. In 1776, the Commission of the London Royal Society, headed by Henry Cavendish made a decision To calibrate the scale so that the water freezes exactly at 32 ° F, and boils, respectively, at 212 ° F (a distance of 180 degrees - a round number, especially for degrees). So today the “normal body temperature” is not 96 ° F, as with Fahrenheyt (now it would be 35.56 ° C), but 97.88 ° F (in the axillary cavity) and 98.6 ° F (in the mouth).

Yes, and finally, about Daniel Fahrenheit's wife. Alas, passionate about his experiments, in his entire life he has never I did not get married. The curious legend was fiction.