While in today’s age, it
might seem like an easy task to get the most accurate temperature. However, it
was not as straightforward in the early ages. It was only 18th
century when a systematic system of measurement was introduced. Before this, no
cohesive method to measure objects or substances was present. So inquisitive
mind might ponder over how the objects in past were measures. Perhaps, the
cursory visual inspection came handy. But how would you measure something that
you can’t even see at those ages? Think of Temperature. There is no doubt that the idea of ‘temperature’ has been around for
centuries but there was no tool to measure it. The scholars from early ages
tend to describe the temperature (the hotness and coldness of it, essentially)
rather than measuring it. It was this knowledge that has been passed around
among cultures in different times that lead to the accurate measurement of
temperature.
Philon’s
Thermoscope
Way
before the digital age and thermometers; scholars observed the different states
of our planet. The liquid would expand if it is exposed to high temperatures
and the same scenario with the solid matter. Looking at this phenomenon; the
Greek engineer Philo Mechanicus issued an extensive paper on the mechanics of
the machine under different temperatures. In one of his compendiums, he
mentioned the use of dipper. The dipper is described as the Philon’s
Thermoscope by the historians. The basic structure of the dipper consists of a
tube that is connected to a hollow sphere inside the water. Whenever the water
temperature rises; the air inside the hollow sphere would cause the sphere to
expand. Similarly, whenever the temperature of the water is cold, the hollow
sphere would contract and cause the water to rise inside the tube. However, it
is unsure that the researchers used this to measure temperature or not. Modern
historians claim that Philon’s Thermoscope had no practical use and the concept
was only limited to his paper. Years passed and the Heron of Alexandria
introduced a much-improved version of the Philon’s Thermoscope. The thermoscope
design consisted of the hollow sphere that is driven with the help of steam. It
followed the same concepts as Philon’s thermoscope but steam was used instead
of the water. Furthermore, Aelius Galenus also introduced a thermoscope for his
medical research. He used the mixture of boiling water and freezing water and
introduced temperature up to eight degrees.
Scholars
of the Middle East
The
Middle East was leading the world in medicine, physics, chemistry, engineering,
and astronomy. If you ask any chemist, they would tell you that it is
absolutely necessary to measure the temperature for the research purposes.
However, it is still not known whether the ancient Middle Eastern scholars used
the Philon’s Thermoscope or the improved version by Heron of Alexandria.
Furthermore, all of the manuscripts by Philo Mechanicus and Heron of Alexandria
are lost in history; we would never know what the original drawings were and
how they came to those conclusions. However, Middle Eastern scholars had
already translated the manuscripts from Philo Mechanicus and Heron of
Alexandria into the Arabic language and managed to save some of their research.
It is still unknown whether the Islamic scholars invented their own versions of
thermoscope for their research or they used the same concepts of Philon’s
Thermoscope. One thing is for sure that they used some sort of scale for their
research to advance further in their research. If you look at the ancient
Arabic manuscripts you will notice that they all described the temperatures
rather than using a scale. The weather was not measured by any instrument
rather they described the droughts, floods, snowfall, etc.
European
Scholars and their Researches
Europe
took the lead in research during the Renaissance. The scholars used to travel
across countries to learn from one another. They published numerous papers on
different subjects including Chemistry, Physics, Astronomy, and Engineering.
They translated the ancient Arabic manuscripts into their native languages to
learn more about the different subjects. However, the careful citations and
attributing sources were not known by the scholars, therefore, it makes it far
more difficult for historians to reconstruct the scientific discoveries. This
is why it is unknown whether the modern thermometer was invented by Galileo,
Salman De Caus, or Santorio Santorio. However, all of these scientists and more
have been attributed to the invention of the modern thermometer. The modern
thermometer was revolutionary antiquity among scientific research, as it makes
it easier for scientists to measure the accurate temperature of different
objects and weather. The earlier version of the thermometer utilizes water
instead of mercury to measure the temperature, it was not as accurate as of the
modern thermometer but it was precise enough to be used for the applications.
Santorio mentions in his paper that he took the early design of the thermometer
from Heron the Alexandria and modified (He effectively added a measuring scale
to the previous thermometer) to measure the cold and warm temperature of the
air. It could also be used to noting the temperature inside the human body.
Nevertheless, it was an important discovery that opened many doors for
scientific discoveries.
Christensen
Romer and Issac Newton
The
infamous Danish astronomer Christensen Romer is known for his discovery about
the speed of light; he proved that the light actually travels at the finite
speed. However, he is barely known for his discovery of the modern thermometer.
He conducted many experiments to measure the lowest and the highest
temperature. He used water to conduct his experiments, and he came to the
conclusion that the lowest temperature that can be measure is 0 degrees because
the water freezes at 0 degrees. Similarly, he used boiling water to measure the
highest temperature. He used brine (salt in water) to measure the temperature
of boiling water and he came to the conclusion that the temperature of boiling
water is 60 degrees. It was quite difficult to standardize the brine water.
Therefore, he used pure water to conduct his experiments. He only had to modify
his discovery slightly for this research and he came to the conclusion that the
water freezes at 7.5 degrees.
Sir
Issac Newton studied Christensen Romer’s research and published his own paper
in the same year. He used the air to measure the temperature rather than water.
He mentioned the water begins to freeze at 0 degrees of heat in the air. In
retrospect, he mentioned the melting temperatures of various objects such as
Lead and Wax. He used the boiling water as one of his reference points and
could measure temperature up to 600 degrees. Sir Issac Newton used the linseed
oil for his thermometer and his scale was considered as the linear scale
between boiling and freezing point.
Advancement of Temperature Scales
The
thermoscope (which dates back to the time of Galileo Galilei) served as a
precursor for the thermometer. This thermoscope was scale-less unlike its
modern counterpart but it could distinguish between cold and hot temperature.
One vital draw-back though, was that the thermoscope could not provide the
exact reading. In 1654 however, the Grand Duke of Tuscany, Ferdinand II,
introduced the very first confined thermometer. Liquid used by Ferdinand II was
alcohol. Even this invention wasn’t huge enough. There were still considerable
drawbacks and the accuracy level was deficient.
However,
in 1714, Daniel Gabriel Fahrenheit (a German Physicist) introduced mercury to
the Christopher Romer’s thermometer. The expansion and contraction of mercury
was in accordance with rise and fall of temperature. Fahrenheit had also
invented an alcohol based thermometer in 1709, which turned out to be even more
accurate. Ten years later, he revealed his so-called “Fahrenheit scale” that
could divide two extreme temperatures of water i.e. freezing and boiling point,
into 1890 degrees. This Fahrenheit scale established freezing point of water at
32 degrees while boiling point of water at 212 degrees.
In the
modern era, Fahrenheit is one of the three major scales for temperature, the
Celsius and Kelvin being the other two.
After the reveal of Fahrenheit
scale, another astronomer (Swedish, this time) Andres Celsius introduced his
very own scale – Celsius scale (as the name would suggest). This scale is also
called centigrade scale as it divided into 100 degrees that separates boiling
and freezing points. The original scale had set boiling point at 0 and freezing
point at100 but Andres Celsius reversed it not too late after his invention.
This scale is followed by the entire world with the exception of United States
that follows the Fahrenheit Scale.
In 1848, Lord Kelvin of Scotland
invented his own temperature gauge that came out as Kelvin scale. His
methodology revolved around the idea of absolute temperature – A temperature
that exists only in theory at which all substance loss all the heat. 0 K is the
coldest temperature on the Kelvin scale (different from the negative readings
on the previous scale). Kelvin is now used as the Standard Unit for the
measurement of temperature. Kelvin is also used mainly in scientific research
and calculation. The units of Kelvin and Celsius are almost the same.
The beauty of these three
measuring unit is that, they could be easily converted into each other
following these simple equations.
F = 9/5 ( C) + 32
|
|
C = 5/9 (F - 32)
|
|
K = C + 273
|
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C = K - 273
|
|
K = 5/9 (F - 32) + 273
|
Unit of Celsius is C, Unit of
Kelvin is K and unit of Fahrenheit is F.
The
basic idea of temperature has been around for centuries. However, due to
advancements in scientific research, it is much easier to measure the accurate
temperature rather than relying on the generic description of the weather. It
was extremely vital for the scientific researchers to measure the accurate
temperature to help them in their research but it was much more difficult to
come up with a standardized scale that would give an accurate measurement.
Throughout history, mankind relied on the description of the temperature.
However, due to various advancements, it is now much easier to measure
temperature. The earlier versions of thermometer such as the Philon’s
Thermoscope utilized water as the scale to measure the temperature but it did
not give accurate measurements. However, it was the step in the right direction
which made the scientist use other elements like Mercury to measure the temperature
rather than water. These inventions formulated into a more cohesive and
diverse measuring systems of scales, namely Kelvin, Celsius and Fahrenheit.
Each has their own significance in history and a different methodology. All
three of these serve purpose of measuring temperature in different fields of
life. These units can be interchanged into their counterparts effectively and
easily, making this system of measurement flexible and agile. Temperature
measurement now is a hold-hold task. Human have grown past the stage of using
extensive equipment to merely check the level of the hotness and coldness of a
substance. A direct and more accurate reading can be taken with a tool the same
size of a finger. All this was only possible due to the advancement of the past
inventions.
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