Difference between Celsius and... Fahrenheit and other temperature scales. Relationship between Fahrenheit and Celsius temperatures

Temperature in degrees Fahrenheit is not exotic now. It is very often indicated on many foreign instruments, especially on medical and meteorological thermometers. The Fahrenheit scale is the most popular temperature scale outside the SI system. We decided to dig a little into history and outline for the inquisitive readers of our portal the history of the creation of this very old, but still popular in some countries, temperature scale.

In many reference books, including Russian Wikipedia, Daniel Gabriel Fahrenheit is mentioned as a German physicist. However, according to the Encyclopedia Britannica, he was a Dutch physicist born in Poland in Gdansk on May 24, 1686. Fahrenheit himself made scientific instruments and in 1709 invented the alcohol thermometer, and in 1714 the mercury thermometer.

In 1724, Fahrenheit became a member of the Royal Society of London and presented it with his temperature scale. The scale was constructed based on three reference points. IN original version(which was later changed) he took the temperature of the brine solution (ice, water and ammonium chloride in a ratio of 1:1:1) as the zero point. The temperature of this solution stabilized at 0 °F (-17.78 °C). The second point of 32°F was the melting point of ice, i.e. temperature of a mixture of ice and water in a ratio of 1:1 (0 °C). The third point is normal temperature human body, to which he attributed 96°F.

Why were such strange, non-round numbers chosen? According to one story, Fahrenheit initially chose the most low temperature, measured in its hometown Gdansk in the winter of 1708/09. Later, when it became necessary to make this temperature well reproducible, he used a saline solution to reproduce it. One explanation for the inaccuracy of the temperature obtained is that Fahrenheit did not have the ability to make a good brine solution to obtain an accurate eutectic equilibrium composition of ammonium chloride (that is, he may have dissolved several salts, and not completely).

Another one interesting story associated with a letter from Fahrenheit to his friend Herman Boerhaave. According to the letter, his scale was created based on the work of astronomer Olof Römer, with whom Fahrenheit had previously communicated. In the Roemer scale, saline solution freezes at zero degrees, water at 7.5 degrees, human body temperature is taken to be 22.5 degrees and water boils at 60 degrees (there is an opinion that this is analogous to 60 seconds in an hour). Fahrenheit multiplied each number by four to remove the fractional part. In this case, the melting point of ice turned out to be 30 degrees. , and the person’s temperature is 90 degrees. He went further and moved the scale so that the ice point was 32 degrees, and the human body temperature was 96 degrees. Thus, it became possible to split the interval between these two points, which amounted to 64 degrees, simply by repeatedly dividing the interval in half. (64 is 2 to the sixth power).

When I measured the boiling point of water with my calibrated thermometers, the Fahrenheit value was about 212 °F. Subsequently, the scientists decided to redefine the scale slightly, assigning an exact value to two well-reproducible reference points: the melting point of ice at 32 °F and the boiling point of water at 212 °F. At the same time, the normal human temperature on this scale after new, more accurate measurements turned out to be about 98 °F, and not 96 °F.

The Fahrenheit scale has been around for 290 years. In English-speaking countries, it was a priority scale in industry, medicine and meteorology until the 60s of the 20th century. Subsequently, European countries switched to the Celsius scale. But there is still a special attachment to the Fahrenheit scale in the United States. Often children or housewives in America have no idea what an air temperature of 20 °C is. Is it a lot or a little? 68°F is another matter. Everything becomes clear to everyone. Therefore, the weather forecast in America always contains the temperature in degrees Fahrenheit.

British newspapers tend to report air temperatures in degrees Celsius, but also provide a conversion table to Fahrenheit. News headlines in the British press tend to indicate degrees Celsius for negative temperatures and Fahrenheit for positive ones. In February 2006 in the largest newspaper The Times An article was published about the psychology of weather forecasting, which stated that -6 °C sounds colder to a person than 21 °F, and 94 °F sounds more impressive than 34 °C.

Converting degrees Fahrenheit to degrees Celsius and vice versa is not difficult. For your convenience, at the bottom of the main page of the site there is an online temperature calculator that instantly converts degrees Fahrenheit to degrees Celsius.

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You've probably seen thermometers marked Fahrenheit degrees more than once: on them, along with one scale that measures temperature in Celsius, there is another one with the letter F. And, you've probably wondered more than once why this Fahrenheit scale is so strange, why there the temperature is higher than ours, to which we are accustomed - for example, 0 degrees Fahrenheit here will be 32 degrees. We will examine this issue later, but for now we will figure out how to convert from the Fahrenheit scale to the Celsius scale and vice versa - to convert the temperature in Celsius to the Fahrenheit system.

How to convert from Fahrenheit to Celsius?

Converting degrees from Fahrenheit to Celsius is easy; this is done using the formula:

(F - 32) : 1.8 = C

where F is the temperature in Fahrenheit and C is the temperature in Celsius. For example, 68 degrees Fahrenheit - how much is it in our opinion, in Celsius? We calculate using the formula:

(68 - 32) : 1,8 = 20

So, 68 degrees Fahrenheit is 20 degrees Celsius.

For fun, let's take another number. American science fiction writer Ray Bradbury has a novel called Fahrenheit 451. How long will it be?

(451 - 32) : 1,8 = 232,77

The answer to the question why the novel is called that way will be a little lower.

How to convert from Celsius to Fahrenheit?

Now the formula for converting degrees Celsius to degrees Fahrenheit:

(C * 1.8) + 32 = F

Let's calculate the temperature of a healthy human body - 36.6 °C - in degrees Fahrenheit:

(36,6 * 1,8) + 32 = 97,88

That is, the temperature healthy person in degrees Fahrenheit will be 97.88.

As they say, we are much warmer in Fahrenheit!

Well, for those who want to quickly, without any mathematics, calculate the required temperature in Fahrenheit and Celsius, “I give you a certificate!” offers a calculator for converting temperatures from Fahrenheit to Celsius and vice versa.

Fahrenheit-Celsius calculator

Why and where is Fahrenheit used?

Using various devices, we don’t even think that quite recently many of them did not exist. Modern thermometers and thermometers arose from the research and talent of outstanding scientists of the past, such as Gabriel Fahrenheit and Anders Celsius.

In 1665, two scientists - the Dutch physicist Christiaan Huygens and the English naturalist and inventor Robert Hooke - came up with the idea of ​​using the melting temperature of ice (the freezing point of water) and the boiling point of water to create a temperature scale. All further researchers and inventors followed this path.

In 1724, the German physicist Daniel Gabriel Fahrenheit (German: Daniel Gabriel Fahrenheit, years of life 1686 - 1736) - a German physicist offered the thermometer and scale he invented to the public. That same year he became a member of the Royal Society, Britain's leading scientific society. The Fahrenheit scale was officially adopted throughout England and all its colonies.

The need for another scale, such as Celsius, subsequently arose due to the inaccuracy and lack of thought of the Fahrenheit scale. Interestingly, to create the scale, G. Fahrenheit used three starting points, two of which were initially inaccurate. He took the winter temperature of 1709 in his hometown of Danzig, which was unusually cold, to be zero - to do this, he immersed the thermometer he invented in a mixture of snow with ammonia and salt.

And 100 degrees on his scale corresponded to the temperature of a healthy person. However, as we calculated above, this temperature is a little more than 97 degrees, and not 100. The fact is that for the body temperature of a healthy person, he took the temperature of his wife, who at that moment began inflammatory process due to the onset of a cold, i.e. her temperature at that moment was slightly higher than the body temperature of a healthy person.

The third starting point - the melting temperature of ice - corresponded to 32 degrees.

18 years later, in 1742, the Swedish astronomer, geologist and meteorologist Anders Celsius (Swedish Anders Celsius, lived 1701-1744) proposed a new temperature scale. However, it differed from ours in that the boiling point of water was taken as 0, and its freezing point as 100 degrees. Also, the scale was not originally called by the name of its creator, but was simply a “centigrade scale,” which in French and English sounded like Centigrade.

The scale was reversed by another Swedish scientist Karl Linnaeus in 1745. Now in it zero was the freezing point of water, and 100 degrees was its boiling point.

Why, given the inaccuracies of the Fahrenheit scale, is it still used? It's all about the conservatism of Americans and... the desire to save money. America was once a British colony and, as a result, adopted the Fahrenheit scale. Now the United States is a leading country in the world and sets the pace in many areas of life, including such a seemingly inconspicuous one as the production of thermometers. It is in the USA that the Fahrenheit scale is predominantly used. The Fahrenheit scale is also used in the Bahamas, Cayman Islands, Palau, Belize, but they do not make weather. In the USA in the 70-80s there was a commission on the transition to metric system, which also uses degrees Celsius, not Fahrenheit. Even Congress issued a special act on the transition to the metric system. However, economists have calculated that retraining personnel, rewriting textbooks, drawings, various technical documentation, signs and much more will require billions of dollars. The commission's recommendations were not binding - it was assumed that the transition to the metric system would be carried out voluntarily. And subsequently the commission was completely dissolved.

Why is the book Fahrenheit 451 called that?

Ray Bradbury and Fahrenheit 451

The title of the book is deciphered in its epigraph: " 451 degrees Fahrenheit is the temperature at which paper ignites and burns.". We have already found out that 451 degrees Fahrenheit is approximately 232.77 Celsius. A more accurate figure will be shown to you by the Fahrenheit to Celsius scale conversion calculator, which is available in the article above.

The work of American science fiction writer Ray Bradbury describes a future world in which books are banned and burned. special teams firefighters. At the same time, anyone who is found with a book is arrested, sent to an insane asylum, and the house of such a “criminal” is also burned. People are given only visual information through television - this is a society that has forgotten how to think and has lost its spiritual connection with each other. The author himself says that with his work he warns about the dangers of state censorship and the stupefying influence of the media.

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> Fahrenheit scale

Fahrenheit temperature scale. Study the formula on how to convert the temperature value into degrees Celsius and what temperature it corresponds to in degrees.

On the Fahrenheit scale, water freezes at 32 degrees and boils at 212.

Learning Objective

• Understand the Fahrenheit temperature scale system and the conversion process to Celsius.

Main points

• The system sets the boiling and freezing marks of water exactly 180 degrees. Therefore, a degree is 1/180 of the space between extreme points.
• To convert °F to °C, you can use the formula: T Celsius = 5/9 (T Fahrenheit - 32). The Fahrenheit and Celsius scales intersect at -40°.
• Almost all over the world, Celsius has replaced Fahrenheit. The traditions are still followed by the USA, Palau, Cayman and Bahamas, as well as Belize.

Terms

• Blend – a mixture of two or more chemicals, reaching the same temperature and not depending on the temperature indicators of the components.
• A brine solution is a solution of salt (usually sodium chloride) in water.

The Fahrenheit scale is used to measure temperature. Based on a scale created by Daniel Fahrenheit in 1724. The unit is degrees Fahrenheit (°F). Here the freezing point of water is 32 degrees, and the boiling point is 212.

Historically, the zero point was calculated by assessing a thermometer immersed in a saline solution. Fahrenheit used a mixture of ice, water and ammonium chloride (salt) in a 1:1:1 ratio. This is a fluorinated mixture that automatically stabilizes the temperature. When recorded, the mark showed 0°F (-17.78°C). The second defining point (32 degrees) represented a mixture of ice and water in a 1:1 ratio. The third (96 degrees) was the approximate temperature of the human body (“blood heat”).

The Fahrenheit system sets the boiling and freezing points of water at exactly 180 degrees, which is 1/180 of the interval between the extreme points. A temperature interval of 1 °F is equal to 5/9 degrees Celsius (°C). To convert °F temperature to °C Fahrenheit, you can use the formula:

T Celsius = 5/9 (T Fahrenheit – 32).

The scales intersect at -40° (-40°F and -40°C). Absolute zero (-273.15 °C or 0K) is defined as -459.67 °F.

Almost all over the world, Celsius has replaced Fahrenheit. The traditions are still followed by the USA, Palau, the Cayman Islands and the Bahamas, as well as Belize.

Comparison of Celsius and Fahrenheit scales

countries, but in the late 1960s and early 1970s it was almost replaced by the Celsius scale. Only in Jamaica, the United States and Canada is the Fahrenheit scale still widely used for domestic purposes.

The scale is named after the German scientist Gabriel Fahrenheit who proposed it in 1724.

On the Fahrenheit scale, the melting point of ice is +32 °F and the boiling point of water is +212 °F (at normal atmospheric pressure). Moreover, one degree Fahrenheit is equal to 1/180 of the difference between these temperatures. The range 0°...+100° Fahrenheit roughly corresponds to the range −18°...+38° Celsius. Zero on this scale is determined by the freezing point of a mixture of water, ice and ammonia, and 100 °F is the normal temperature of the human body (however, Fahrenheit was wrong in the last measurement: the normal temperature of the human body is 97.9 °F). According to one version, Fahrenheit took the body temperature of his wife, who was unhealthy at the time the temperature was measured, to be 100 degrees on the temperature scale - this is what caused the centigrade point to shift by 2.1°F, and not the error of the measurement itself.

Arithmetic conversions

One degree Fahrenheit is equal to 5/9 degrees Celsius, and Fahrenheit temperature is related to Celsius temperature by the following formulas.

From Celsius to Fahrenheit:

From Fahrenheit to Celsius:

Links

• Converting temperature expressed in degrees Fahrenheit to other systems

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See what the “Fahrenheit scale” is in other dictionaries:

FAHRENHEIT SCALE, a temperature scale based on the freezing point (32°F) and boiling point (212°F) of water. The interval between these points was divided by 180 equal parts. Although the Fahrenheit scale was later replaced by the Celsius scale, its... ... Scientific and technical encyclopedic dictionary

Fahrenheit- Farenheito skalė statusas T sritis Standartizacija ir metrologija apibrėžtis Temperatūros skalė, kurioje vandens virimo taškas atitinka 212 °F, o jo užšalimo taškas – 32 °F. atitikmenys: engl. Fahrenheit scale vok. Fahrenheits Skala, f rus. scale... Penkiakalbis aiškinamasis metrologijos terminų žodynas