8 temperature units that you may or may not know?
We all use a temperature scale every day just to know the outside temperature or to regulate the temperature in our room.
The behavior of temperature is so obvious that we no longer think about it.
But did you know there were 8 popular and different temperature units?
And even if you count the smaller number, there were even more than 30 people.
Fortunately, we do not need to use all of them. Some are not used and some are only used for specific applications.
You may be wondering why we have so many different temperature units. Wouldn’t it be much easier to have a unit?
No really, that’s why there are different temperature units. In this article, we will explain the reason.
Let’s first look at these 8 temperature units
Newton Temperature Scale (1701)
You must already know Mr. Isaac Newton (1643-1727 pounds). There is a very famous story about him that says that he discovered the theory of gravity when he sat under an apple tree and an apple fell on his head.
I do not know if this is entirely true, but he certainly discovered gravity and much more.
Newton was an English mathematician, astronomer, theologian, author, and physicist. One of the greatest scientists to date, comparable to Einstein, with discoveries such as color spectrum (using a glass prism) or three laws of motion.
In addition to all this interest, he was the first to develop the temperature scale in 1701.
He uses his thermometer, which is made of a thick glass tube 1.5 to 2 inches in diameter and filled with linseed oil, to measure the melting temperature of snow. This temperature became his first set point in temperature. So he assigned it to 0.
The second defined point of temperature on the Newton scale was body heat, which he described as “external body heat in the normal state.” He defined this temperature as 12 degrees.
Yes, Newton did not talk about temperature, although he called his instrument a thermometer, but he called it temperature.
So now that he has calibrated his thermometer, he can start measuring the temperature, but only in the lower range because flaxseed oil reaches boiling temperature at 287 ° C (depending on purity). Second, the oil begins to decompose around its boil, which can change its coefficient of expansion and make the thermometer useless.
Although his flax thermometer could also measure small negative temperatures, Newton never examined this part of the temperature scale. Therefore, Newton’s initial measurement scale was not negative.
Newton did not intend to invent the thermometer for everyday use. Since he was appointed head of the Royal Mint, a coin-producing company for the United Kingdom, he was more interested in determining the boiling points of metals.
To calibrate his thermometer to a temperature above body temperature, he heated a very thick piece of iron until it was hot.
He described the temperature of hot molten iron as the temperature of live coal in a small kitchen stove made of bitumen coal and burns without the use of rust.
You do not want to be frustrated if you cannot get the right pitch so invest in a good capo.
So, to do this, he placed small pieces of various metals on his molten iron block. These metals were alloys of tin, lead, and bismuth, which melted relatively rapidly with the heat of the iron block.
As the iron cools, the alloys solidify one by one at their own temperature.
Newton recorded the time when the iron block began to cool, as well as the time at which the various alloys solidified. Finally, he pointed to the cooling time of iron, the temperature of which can be measured directly with a flaxseed oil thermometer. This means that it must be cooled to body temperature.
He could now calculate the cooling law to calculate the temperature at which the alloys solidified and the temperature of the iron at the beginning of the experiment.
He found 7 newly defined items on the temperature scale:
40 ° N: Melting point of an alloy consisting of one part lead, four parts tin and five parts bismuth
48 ° N: Melting point of the alloy consisting of equal parts of bismuth and tin
57 ° N: Melting point of the alloy consisting of one part bismuth and two parts tin
68 ° N: Melting point of an alloy consisting of one part bismuth and eight parts tin
81 ° N: Bismuth melting point
96 ° N: melting point of lead
192 ° N: Heat iron with heat
If you’ve never heard of the Newton’s temperature scale, it’s okay, it’s no longer used.
Temperature scale Rømer (1701)
Ole Christensen Romer (1644 ° 1710 بود) was a Danish astronomer who studied in Copenhagen (Denmark) and later went to work in Paris.
He also worked closely with astronomers such as Gottfried Leibniz, Christian Huygens and Isaac Newton.
In 1676 he was the first to calculate the velocity of Jupiter, one month from the planet Jupiter, using his observations.
He found that light travels at a speed of 225,000 kilometers per second.
Well, it’s not that accurate, because we now know it’s 299,792,458 km / h (in a vacuum).
When he returned from Paris in 1681, he became professor of astronomy at the University of Copenhagen and a few years later was appointed director of the Roundtower Observatory.
He had built his own transit device at home, which he used to measure the position of stars, but this equipment was affected by light refraction and temperature changes.
He needed a thermometer to compensate for temperature changes.
Finding a good thermometer at that time is not an easy task. Even if you find one, it does not have a temperature scale. Let alone that it can be used for scientific purposes.
So he decided to make one on his own and experimented with a glass tube filled with saffron stained with spiritus vini.
This means that he used wine as a thermometer liquid.
This had a number of advantages. Since wine is mainly a mixture of water and alcohol, it has a higher linear expansion curve than pure water. Remember that water behaves a little strangely at about 4 ° C.
Later calculations show that this mixture contains 39% alcohol by volume. They had strong wine at that time. Not surprisingly, the light speed calculation was a bit off.
At this point, he had a glass tube and liquid to pour.
Now, how did he calibrate his thermometer?
Well, when he realized that air pressure above the liquid could affect the height of the liquid column, he sealed the glass tube on top of it.
He then immersed the bubble part of his thermometer in ice water and placed a mark on the glass tube above the liquid column.
He then immersed it in boiling water and marked another mark on the pipe.
So now his thermometer has been calibrated. All that was left was to put the numbers on the scale.
He did not want negative numbers because it was very confusing and people might forget to put negative signs in front of the number when writing the temperature.
To prevent this, he divided his scale into 7 equal parts and placed 1 equal part under the sign of the freezing point of water, so that this scale consists of 8 equal parts.
He wrote the number 0 at the bottom of the scale and 60 at the top. Between the two symbols, he created a linear distribution of degrees. According to this scale, the freezing point of water was 5.7 degrees Celsius.
The fact that he chose number 60 for the boiling point of water was not surprising.
As an astronomer, he used the number system of sixties (base 60) to perform calculations and measure time, angles, and geographic coordinates.
This was the first thermometer that could be calibrated repeatedly with great precision, as boiling and freezing points of water are readily available.
However, over the years, better solutions emerged and the Roemer Temperature Scale became obsolete.
Fahrenheit Temperature Scale (1724)
Daniel Gabriel Fahrenheit (۶ 1686-1736) was born to a wealthy parent in Danzig (now Gdaسsk, Poland). He paid in medicine.
His guardian, who had two sons and two brothers, did not support university education and sent him to Amsterdam, the Netherlands, to prepare for an accounting course.
Fahrenheit, however, was more interested in tools and equipment than in reading books. So it was not long before he began to make his own thermometers, the old-fashioned way, with the same divisions as the Florentine thermometers:
90 degree above ‘extreme heat’
0 degrees for ‘medium heat’
90 degree lower limit for ‘severe frostbite’
In 1708 he went to Denmark to meet Romer. It turned out that this was a serious meeting that had a major impact on his later work.
He learned from Romer that good, continuous thermometers are in great demand for scientific work. But they must be the same in order for the measurements to be compared.
He was then convinced that the thermometer needed an accurate temperature scale and that the scale should be renewable.
He got the idea of a temperature scale from Ramer but did not like decimals in units, for example. 7.5 degrees for freezing water and 22.5 degrees for body temperature.
So he rounded them up to 8 and 24, using the freezing point of water and body heat as calibration points.
This is the scale that is actually the main scale of Fahrenheit. He changed this several times for various reasons.
The exact time of these changes is not entirely clear, as Fahrenheit did not record his experiments. All our information has been obtained from his letters to other scientists.
At some point in time, which must have been around 1713, he multiplied all the numbers on his scale by 4, giving the scale a range of 96 degrees Fahrenheit with a freezing point of water at 32 degrees Fahrenheit.
This makes the scale more accurate because there were more precise subsections that were useful for scientific purposes when using his thermometers.
Another reason could be that 64 degrees between his two calibration points (96 degrees and 32 degrees) is much easier to build in equal parts, because 64 is the power of the eighth 2.
So with successive divisions by each part of the scale, he could easily place the numbers on his scale.
Some say that he used salt water, a mixture of salt and water, which cooled him to freezing point and used this as a calibration degree for 0 degrees Fahrenheit.
But this is not provable and it is very doubtful because in the letters there are different mixtures, none of which are frozen at exactly 0 degrees Fahrenheit.
It is more likely that he used salt water as his thermometer test point but calibrated it by freezing it in water.
Fahrenheit used alcohol as a thermometer, but was not satisfied with it because it was difficult to obtain alcohol with the same composition, and so the coefficient of expansion was always different.
Second, the boiling point of alcohol is low, so it is impossible to measure high temperatures.
To solve this problem, he began new experiments with different thermometer fluids until he finally discovered that mercury was ideal.
Fahrenheit was the first to use mercury as a liquid in a thermometer.
With mercury he could produce thermometers that could measure up to 600 degrees Fahrenheit.
Further benefits of mercury include:
Low freezing temperature: -38 ° C
Welding temperature above 380 ° C
The coefficient of expansion is the same at all temperatures
Does not evaporate
Silver is easily visible
We now know that mercury is also toxic and therefore its use is prohibited.
Around 1713, he stopped using body temperature or “blood heat” as a calibration point because he found it too unreliable.
This was while realizing that the body temperature of young people is higher than that of older people.
Instead, he used the boiling point of water as his high-calibration point. This corresponds to 212 degrees Fahrenheit.
He had a mercury thermometer calibrated at the freezing point of water, and he used it as his standard thermometer, comparing it to all the other thermometers he had made.
Fahrenheit, who had never been highly educated, did not fully understand the mathematics of his inventions, but his perseverance and constant experimentation helped him to make accurate measuring instruments.
After a few years of travel, he finally settled in Amsterdam in 1717 and built thermometers, barometers and thermometers.
He finally died in 1736 after spending all the money he had inherited from his parents and the money he had earned for experiments.
Rheumor Temperature Scale (1731)
René Antoine Ferchault de Réaumur (1683 – 5 1757), born in La Roche (France), was a French writer.
He studied philosophy, civil law and mathematics and in 1703 went to Paris to continue his studies in mathematics and physics.
In 1708, at the age of 24, he was elected a Fellow of the Académie des Sciences, an institute promoting scientific research in France.
Throughout his life, he wrote many scientific papers on many disciplines, from geometry to bird nest shapes and everything in between.
As an entomologist, he observed insects, which led to the discovery of a number of elements, such as the possibility that spiders could be used to produce silk or the process of making bees from wood fibers to build their nests.
Because accurate measurements of temperature were important in physics, and the thermometers used for this purpose were usually not very accurate, he developed his own thermometer in 1731.
Rheumor wanted to produce comparable thermometers that could be used for scientific research.
Fahrenheit and Rheumor thermometer image (De Lakenhal Museum Collection, Leiden)
He defined his thermometer by a single fixed point, the freezing point of water, which he had determined at 0 degrees on the temperature scale.
As a thermometer, he preferred alcohol (ethanol), which was diluted water, to mercury, because it had a higher coefficient of thermal expansion. Ethanol has a coefficient of 750 ppm / K, while for mercury it is 182 ppm / K.
In this method, a significant difference is observed for the same temperature change on the scale.
Rheumor carefully selected the combination of alcohol and water so that the calorimetric fluid increased by 8% by volume as it warmed from the freezing point of water to the boiling point of water.
This means that 1000 parts at the freezing point of water gives 1080 parts at the boiling point. This led to the definition of a boiling point at 80 degrees.
When applying linear divisions between 0 and 80 degrees, he ignored the non-linearity of the expansion of liquids and did not consider the effect of atmospheric pressure, so Rheumor did not achieve his goal of producing comparative thermometers.
In addition, thermometers were not suitable for measuring higher temperatures because alcohol had a lower boiling point. This makes it unsuitable for many applications.
However, his thermometers were widely used in Europe. Mostly in France, Germany and Russia.
Around 1790, France introduced the metric system and thus chose the Celsius scale, but the Rheumor scale was used in some parts of Europe until the mid-nineteenth century. In Russia even until the early twentieth century.
In fact, the rheumatoid scale is still used today in some parts of the food industry. For example, to measure the temperature of milk when producing cheese in Switzerland and Italy, or to cook sugar syrup to produce pickles in some Western European countries.
Delisel Temperature Scale (1732)
Joseph-Nicolas Delisel (1688-1768 ° C) was a French astronomer and surveyor. Born in Paris, he first pursued classical studies, but soon moved on to astronomy. He entered the French Academy of Sciences in 1714.
In 1725, Caesar Ross Peter the Great summoned him to St. Petersburg to establish and run the School of Astronomy. He only arrived there in 1726. Caesar was dead at that time.
In 1740, Delizel traveled to Siberia to observe Mercury moving around the Sun. He left St. Petersburg for the United States on February 28, 1740, and arrived in Bryuzovo, Siberia, on April 9. It was a 42-day trip.
But he had no chance. All his efforts were in vain because on April 22, the sun was covered by clouds. Delizel was unable to observe astronomical observations.
During this trip, he made many scientific observations about the vegetation and wildlife of Siberia. Despite all his efforts in astronomy, he became better known for his invention of the Delisel temperature scale.
He built his first thermometers in 1724 and used wine as a thermometer. Unlike Rheumor, he did not dilute the wine with water. The temperature of the Paris Observatory was the only fixed point he used to calibrate his thermometers.
Choosing the temperature of a random warehouse as a fixed point may seem a little strange, but at the time many scientists believed that the temperature of underground places was constant. In particular, they were convinced that this temperature corresponded to the average internal temperature corresponding to the sun since the creation of the earth. This is not true, as we found out later.
From 1732 he changed his fixed point to the boiling point of water and indicated it by 0 degrees.
But there is a serious problem with wine as a thermometer, because wine boils at a lower temperature than water. Wine thermometers could not easily withstand the heat of boiling water.
To solve this problem, he had to change his thermometer fluid to mercury, which has a boiling point higher than the boiling point of water.
Initially, the scale had 2,400 sections, commensurate with the winter in St. Petersburg. Each part corresponds to one hundred thousandths of the mercury contraction in the thermometer, with higher values at lower temperatures.
This means that the Delzel scale was the inverse scale, in which the increase in cold was shown by higher numbers. It had the advantage that in a wide range of applications, numbers were never negative.
In 1738 the small scale was reused by Josia Weitbrecht, a professor of medicine and anatomy in Germany. He kept 0 degrees as the boiling point of water but set 150 degrees as the freezing point of water
The Delizel scale was used in Russia for almost 100 years in the eighteenth and nineteenth centuries.
Celsius Temperature Scale (1742)
Anders Celsius (1744-1701) was a Swedish astronomer and physicist who was born on November 27, 1701 in Uppsala, Sweden.
He was a professor at Uppsala University and had been teaching astronomy since 1730. As an astronomer, he analyzed changes in the Earth’s magnetic field and developed tools to measure the brightness of stars.
In 1741 he established an observatory in Uppsala with several others, but he became famous for his invention on the Celsius scale in 1742.
Celsius created his temperature scale with only 2 points defined based on the physical properties of water.
The zero point (0 ° C) was defined at the boiling point of water and the second point (100 ° C) was defined at the freezing point of water, both referring to the standard atmospheric pressure. Yes, this is exactly the opposite of the Celsius scale we know today.
The reason for choosing the inverted scale is because at that time the thermometer was mainly used to measure outside temperature or body temperature, both of which were in the range of -20 to +40 degrees Celsius.
Selecting 100 ° C at the freezing point of the water prevented it from freezing out of negative numbers.
For people today it feels a little unpleasant that it can rise due to lower temperatures, but in the end everyone got used to it.
A few years after the invention of the Celsius scale, some scientists began to use the inverse scale with 0 ° C defined at the freezing point of water and 100 ° C defined at the boiling point of water.
Especially biologists, on the contrary, the scale was interesting. Because plants are at risk of death at 0 ° C because the water is frozen, the scientists found that the temperature below the freezing point of the water is negative and the higher temperature is positive.
In fact, it is not clear who first reversed the scale. Some say it was Carlos Lenaeus (Lena), professor of medicine and head of the botanical garden at Uppsala University; others think it was Martin Stromer who succeeded the late Professor A. Celsius to the chair of astronomy.
Because at 100 degrees Celsius we originally called it the Celsius scale, it was 100% Latin, but in 1948 the name was changed to the Celsius scale, a name that is still used today.
It was the “Conférence Général des Poids et Mesures” that decided to change the name because “degree” was already used as a unit of measurement and could be confused with “degrees Celsius”.
Celsius died of tuberculosis in 1744 at the age of 42.
Kelvin Temperature Scale (1848)
William Thompson, also known as Baron Kelvin 1 (1824 † 1907 و) and also Lord Kelvin, was a Scottish-Irish physicist and mathematical engineer.
Born in Belfast, Northern Ireland, he worked at the University of Glasgow in mathematical analysis of electricity and thermodynamics.
He, along with many other scientists, played an important role in formulating the first and second laws of thermodynamics.
In 1866 he was executed by Queen Victoria for his theoretical work on submarine telegraphs and his inventions of submarine cables used in the Freemasonry Telegraph Project. He was honored with the title “Sir” to use in front of his name: “Sir William Thompson”.
Because of his achievements in thermodynamics, and because of his opposition to the government for Ireland in England, he was fascinated in 1892 and Baron Kelvin became from Larz (a city in Scotland). Kelvin is the name of a river that flows near his laboratory at the University of Glasgow.
William Thompson became the first British scientist to join the House of Lords in England. Hence he is also called Lord Kelvin. A lord is a title in England formally given to a baron or a member of the House of Lords.
Kelvin, like many other scientists at the time, supported the idea of an absolute minimum temperature, which they called the “infinite cold.” According to classical physics, this would be the temperature at which all motion stops completely.
In other words, everything is frozen and there is no movement of atoms.
In 1848, he published an article on the Absolute Thermometer Scale stating that the absolute minimum temperature was -273 ° C. Now, this value has been corrected to -273.15 ° C.
With this knowledge in mind, he created a completely new absolute temperature scale with a zero sign at the absolute minimum temperature. Therefore ,
K = -273.15 ° C0.
This means that negative temperatures on the Kelvin scale are impossible because nothing can be colder than absolute zero.
The divisions on the Kelvin scale are exactly equal to degrees Celsius, but the Kelvin unit is not expressed in degrees, so there is no degree symbol.
While the relative temperature scale, for example Fahrenheit or Celsius, compares the temperature of an object with a selected fixed point (such as the freezing point of water), the absolute temperature scale works differently. They show the temperature compared to absolute zero.
In this way, the absolute temperature scale not only shows the temperature of an object, but also provides information about the kinetic energy of atoms and their molecules. Mechanical energy is zero at zero Kelvin and higher at higher temperatures.
Since 1954, the General Conference on Weight and Measurement (CGPM) has approved the Kelvin as the basic unit of thermodynamic temperature and has defined it:
Kelvin, the unit of thermodynamic temperature, is the fraction of 1/273,16 of the thermodynamic temperature of the triple point of water.
Because the triple point of water (273.16 K) is a very accurate and reproducible temperature, it is selected as a fixed point on the Kelvin scale.
The water used to calibrate the temperature measurement has just no water. In 1968, it was recognized by the International Atomic Energy Agency (based in Vienna) as the Vienna-Ocean Water Standard (VSMOW). The term “ocean water” refers only to the evaporation of ocean water in the water cycle as the main source of fresh surface and groundwater.
In addition to the triple point of water, 16 other defining points have been selected by international agreement, from the freezing point of helium to the freezing point of copper.
Unless you are a scientist or an engineer, you will use the Kelvin scale a little because it is used for scientific purposes only.
Temperature Scale Celsius (1859)
William John McCormack Rankin (1872 † 1872) was a Scottish professor of civil engineering and mechanics and had a keen interest in railway engineering, molecular physics and thermodynamics.
Born in Edinburgh, Scotland, he moved to Glasgow in 1851 to work at the University of Glasgow, where he taught theory and practice in civil and mechanical engineering.
Rankin was particularly interested in thermodynamics and developed a complete theory of steam engines and virtually all heat engines. He also had many interests in other fields of science, mathematics and engineering.
In 1859 he developed his own temperature scale. This scale was thermodynamic, just like Kelvin, but the Rankin scale was based on degrees Fahrenheit instead of degrees Celsius, as was the case with Kelvin.
The Rankin temperature scale starts from absolute zero and each division is one degree Fahrenheit. Therefore, the temperature R0 is equal to 0K or -459.67 degrees Fahrenheit.
The triple point of water, which is R 491,688, is used as a fixed point on the scale. The water used here is also in accordance with the Vienna Standard on the Vienna Ocean Water Standard (VSMOW).
Most people write the Rankine unit with an R rating, but the US National Institute of Standards and Technology (NIST) recommends using a rating symbol to emphasize its similarity to Kelvin.
The Rank Temperature Scale applies only to scientific applications where the formulas are expressed in units. It can be used for calculations such as radiant heat transfer, entropy change, thermal efficiency of carrot engine or ideal gas engine.
The Rankin scale has been largely replaced by the Kelvin scale. Today, I find it difficult to find scientific work using the Rankine unit. But if you want to dive into old science articles, knowing this temperature scale can be helpful.
Rankin, single and childless, died on Christmas Eve 1872 at the age of 52.
Why do we have different temperature scales?
As I promised you at the beginning of this article, let me explain why we have different temperature scales.
Throughout history, in the 18th and 19th centuries, there has been a great deal of knowledge about the best way to measure temperature.
First of all, which thermometric fluid should be used? Second, how do we graduate the scale? And third, how do we calibrate it?
Many experiments continued, and some scientists, often astronomers who had to make up for their measurements of temperature changes, began to build their own thermometers.
Some of them did a good job and managed to build a reliable thermometer. Others failed, and their thermometers were quickly forgotten.
Thus, there has been and still is a historical evolution in the use of the temperature scale. We did not just create one scale, we created different scales.
Some of these scales were widely used in Europe and Russia. Changing from one scale to another takes time to persuade people to use another scale. As you know, people are always resisting change.
The temperature scale, like those created by Newton, Roemer, Rheumor, or Delizel, was replaced by the Celsius scale when many countries began to introduce the metric system around 1790. Several countries maintained the imperialist or customary system and continued to measure the temperature at Fahrenheit. Today these countries are the United States, Liberia and Myanmar. Some other countries use both Fahrenheit and Celsius.
Kelvin and Rankin scales are used only for scientific reasons, so Kelvin has almost the largest scale, and Rankin is used only in a few specific engineering disciplines, such as thermal power plants.
So, this includes only 3 different scales, which are Fahrenheit, Celsius and Kelvin. Knowing that the Fahrenheit scale is collapsing, there may be only two scales in the future. In Nakhai, only Kelvin may remain, although it may seem a bit strange to show the outside temperature by 3 degrees.
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