Know the temperature of your body, the air outside the window, the water filling the bath or pool, and many other phenomena and objects around you modern man, has become commonplace, and the measurement process has become simple and accessible to everyone. If you ask a question about what temperature someone or something has, it is unlikely that the numbers given in response will cause bewilderment, turning out to be completely uncharacteristic.

The reason for this is the widespread measurement of a given physical quantity on the Celsius scale in almost everything. However, in the USA, Canada, England and a number of other countries, determining temperature using the Fahrenheit system is common in everyday life. To understand each other, it is enough to imagine the range of each scale and their ratio in Fahrenheit and Celsius.

Object of measurement, or what is temperature?

The term comes from the word temperature (translated from Latin as “normal state/displacement”). From the point of view of physics, this is a quantity that characterizes the mobility of the molecules of a substance, its internal energy. The faster the particles move, the more they collide with each other, the higher the temperature value. Hence, when heated, the volume of bodies and substances increases. But temperature and heat are not identical concepts. Bodies heated to the same temperature have different abilities to heat foreign objects (for example, the difference in the boiling speed of a kettle on a small and large burner).

Invention of Daniel Gabriel Fahrenheit

The Dutch physicist, born in 1686 in the Polish city of Gdansk, began early scientific activity. He assembled measuring instruments with his own hands and at the age of 23 he invented and 5 years later - mercury. In 1724, Fahrenheit proposed his system for measuring temperatures to the scientific community. Later it underwent some changes. The scientist’s goal was to create a scale without a negative value, so he took the most low temperature, known at that time - melting a mixture of ice, water and ammonia. To determine one division on a thermometer - a degree - the physicist used the range between the indicator of melting ice and boiling water, dividing it into 180 equal parts.

Andres Celsius system

Born in 1701 in Sweden, the astronomer, geologist and meteorologist proposed his scale in 1742. Initially, the boiling point of water was used as zero, and its melting temperature as 100 degrees. The direction of the most widespread scale in the world today was changed by Celsius' contemporary Carl Linnaeus in the year of its author's death - 1744. Thus, it acquired its current form. Temperatures lower than the melting point are measured in the same way as higher temperatures, but have a negative value.

Relationship between Fahrenheit and Celsius

Indicative for comparing the two systems will be the well-known temperature standards - boiling water, melting ice, the norm for a healthy human body.

The numbers will be as follows - 100°, 0° and an approximate average value ranging from 36 to 37° on the Celsius scale. In Fahrenheit the ratio will be 212°, 32° and approximately 98°. One of the key concepts in temperature measurement is absolute zero - a theoretical value that is the reference point and standard for any use of systems. This quantity is characterized by the absence of movement of matter particles. In the ratio of Celsius and Fahrenheit, these figures are equal to -273.15 and -459.67 degrees.

Converting values ​​from one system to another is quite simple. For such an arithmetic conversion, there is a formula that is used in two directions (depending on the original indicator). The ratio to Celsius is 1:5/9.

Thus, to convert the Fahrenheit thermometer readings to the Celsius system, it is necessary to subtract 32 from the original value and multiply by 5/9.

Accordingly, the inverse conversion is carried out according to the formula in which the Celsius scale data is multiplied by 5/9 and 32 is added.

To understand both systems and use them in everyday life, it is not at all necessary to use mathematical calculations every time. If the use of an unfamiliar system is necessary, just a little practice, and the approximate value of the data in the ratio of Fahrenheit and Celsius will be easily determined “by ear”.

The winter of 1709 was exceptionally severe in Western Europe. Such severe and prolonged frosts have not been there for a century. Naturally, the physicist Fahrenheit, who lived in the city of Danzig, charting constant points for the thermometer he invented, then took for zero the temperature the degree of cold below which the frosts in his city in the winter of 1709 did not reach. It was cold obtained using a cooling mixture of ice, table salt and ammonia.
For another constant point of the thermometer, Fahrenheit, following the example of a number of his predecessors (including Newton), chose the normal temperature of the human body. In that era, there was a widespread belief that the air temperature never rises above the temperature of human blood, and such heating of the air was considered fatal to humans (the opinion is completely erroneous).
Fahrenheit initially marked this second constant point with the number 24; the number of degrees was equal to the number of hours in a day. But when practice showed that such degrees were too large, Fahrenheit divided them into quarters and the temperature of the human body was designated as 24 . 4 = 96. This determined the final division length, corresponding to one degree. Laying degrees down the scale from bottom to top, the scientist obtained the boiling point of water at 212˚.
How can we explain that Fahrenheit did not take the boiling point of water as the second constant point of his thermometer? He refrained from doing this because he was aware of the variability of this temperature (depending on air pressure). The temperature of the human body seemed to him more reliable in terms of constancy. It is interesting to note, by the way, that, as is easy to calculate, normal temperature Our body temperature was considered in that era to be a whole degree lower than now (35.5˚C).
Ya.I.Perelman. "Do you know physics"? M., 2007. P.221-222.

I remember as a child, reading some novel translated from English, I was perplexed by something like this: a mother, having measured the temperature of a sick child, saw 98 degrees on the thermometer and calmed down. Imagination pictured a villainess cooking an unfortunate baby for dinner... then it dawned on him that humanity does not live by Celsius alone. In fact, everything was fine with the child - the temperature was 36.6°C *).

However, I was not the only one who was mistaken. I can’t help but quote Pierre Daninos’s wonderful book “The Notes of Major Thompson”:
On one of my first visits to France, completely exhausted by a severe flu and an equally difficult crossing of the English Channel, which combined to hit me, I decided to stop for a while at one of the hotels in Calais to take my temperature. And since the thermometer showed only 40.3°, I, having calmed down, set off, raising the top of my car and lowering the windshield, but suddenly I remembered that I was with these damned inhabitants of the continent, for whom everything is not the same as with good people. I immediately began converting my continental temperature to Fahrenheit, and my kilometers to miles.
Just as I was about to multiply 274 by 5, then divide by 9 and add 32° to the distance from Calais to Paris, I saw a car rushing straight towards me, and suddenly realized that, carried away by my calculations, I had forgotten about the existence of right-hand traffic. I moved to the right side in time and braked, and the driver flying towards me, pausing for a minute, shouted right in my face:
-Are you crazy, or what? This is not roast beef for you to chew!
Then, concluding from my silence that the meaning of his words had not reached me, he, already setting off, looked at me again and tapped his forehead several times with his index finger.

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Initial value

Converted value

kelvin degrees Celsius degrees Fahrenheit degrees Rankine degrees Reaumur Planck temperature

More about temperature

General information

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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 the 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, the Cayman Islands and the 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 dipped in 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

Temperature scales. Celsius scale, Kelvin scale, Reaumur scale and Fahrenheit scale. Temperature scales in degrees Celsius, Kelvin, Reaumur, Fahrenheit from +100°С to -100°С

Temperature scales Celsius, Kelvin, Reaumur, Fahrenheit

There are several temperature scales. Celsius scale, Kelvin scale, Reaumur scale, Fahrenheit scale. The division values ​​in the Celsius and Kelvin scales are the same. The Reaumur scale is coarser than the Celsius and Kelvin scales due to the fact that in the Reaumur scale the price of a degree is higher. The Fahrenheit scale is the opposite, more precisely because there are one hundred eighty degrees Fahrenheit for every one hundred degrees Celsius.

Comparison table for Celsius, Kelvin, Reaumur, Fahrenheit scales

Comparison table of zero values ​​of the Celsius, Kelvin, Reaumur, Fahrenheit scales

Celsius

The Celsius scale is a centigrade thermometric scale that has two main points:

The first point corresponds to 0°C Celsius, the second point corresponds to 100°C Celsius.

Kelvin scale

The Kelvin scale is an absolute temperature scale in which degrees are counted from the temperature of absolute zero. The temperature of absolute zero is 273.16°C lower than the melting temperature of ice.

Reaumur scale

The Reaumur scale is a thermometric scale that has the same two main points as the centigrade scale:

Melting point pure ice at normal pressure;

Boiling point clean water at normal pressure.

The first point corresponds to the number 0°R of the Reaumur scale, the second point corresponds to 80°R of the Reaumur scale. The Reaumur scale was introduced French physicist R. Reaumur in 1730.

Fahrenheit

Fahrenheit scale - temperature scale, used in the USA, England and a number of other countries. On the Fahrenheit scale, the melting temperature of ice corresponds to 32°F, and the vapor temperature of water boiling at atmospheric pressure, corresponds to 212°F. One hundred degrees on the Celsius scale corresponds to one hundred and eighty degrees on the Fahrenheit scale.

Celsius

The Celsius scale is used to measure temperature in everyday life and in science. The temperature in degrees Celsius is broadcast by radio stations and television channels; the temperature in degrees Celsius is shown on the Internet by weather informers. Many thermometers, car climate control dials, and air conditioner remote control displays are calibrated in degrees Celsius.

Kelvin scale

The Kelvin scale is used in science. The temperature of absolute zero corresponds to zero degrees on the Kelvin scale. In photography, white balance corresponds to a specific color temperature. For example, white balance on a sunny day (or flash light) corresponds to a color temperature of 5500 K.

Reaumur scale

The Reaumur scale is used quite rarely in most countries.

Fahrenheit

The Fahrenheit scale is used in the USA, England and some other countries. Sometimes in hotels you can find air conditioners whose remote controls are calibrated in degrees Fahrenheit.

For convenience, you can use the table for converting degrees Celsius to Fahrenheit:

Short version of the table converting degrees Celsius to degrees Fahrenheit: