Temperature is energy that is measured with an instrument called a “thermometer,” which comes from the Greek words “thermos” (hot) and metron (measure).
The intensity of heat, or the amount of heat energy contained in a substance or medium such as air, a measure of water, or the surface of the sun, can be measured using the baselines chosen by scientists.
There are 3 commonly used systems for measuring temperature: Fahrenheit, Celsius, and Kelvin.
According to a 2019 report in the journal Nature Public Health Emergency Collection, the ancient Greek physician Hippocrates claimed that the human hand could be used to judge whether a person had a fever as early as 400 B.C. Accurate instruments for measuring human body temperature were not developed until the 16th and 17th centuries AD.
Fahrenheit… the first accurate thermometer
In 1714, he revealed “Daniel Gabriel Fahrenheit-Dutch-born physicist, inventor and maker of scientific instruments – about a mercury-based thermometer. Mercury is a liquid metal that expands and contracts based on ambient temperature.
When Fahrenheit placed mercury in a sealed tube marked with a numbered scale, he saw the mercury rise and fall when exposed to different temperatures. It was the world’s first known practical and accurate thermometer, according to the UK’s The Royal Society.
Fahrenheit based his invention on the alcohol-based thermometer of Danish scientist Ole Romer.
Romer described his temperature scale as a “zero mark” when brine freezes, and 60 degrees at the boiling point of water.
However, the Fahrenheit thermometer was more accurate. He used the same freezing and boiling reference points on the Romer scale, but he doubled the scale for an increase in accuracy. The four reference points on the Fahrenheit scale are zero at the freezing temperature of brine, 30 at the freezing point of regular water, 90 at the body temperature, and 240 at the boiling point of water.
Fahrenheit published a paper describing its scale in a journal.Philosophical translations(Philosophical Transactions) in 1724.
In the same year, Fahrenheit was included in the Royal Society, the National Academy of Sciences of the United Kingdom, and the Fellowship of the Royal Society resulted in special acceptance of the Fahrenheit thermometer in England, and thus also in North America and later the British Empire.
The Fahrenheit measurement system is sometimes referred to as part of the British Imperial System, because it traveled around the world with the British Empire at the time.
After Fahrenheit’s death in 1736, the Fahrenheit scale was recalibrated to make it slightly more accurate. The exact freezing and boiling points of ordinary water without salt are set at 32 and 212 degrees Fahrenheit, respectively. The normal human body temperature has also been set at 98.6. Temperatures are often expressed in Fahrenheit as a number followed by (℉) or simply “F”.
Celsius..a more scientific scale
“It must be recognized that Anders Celsius was the first to carry out and publish accurate experiments aimed at defining an international temperature scale on scientific grounds,” wrote Olof Beckmann, a solid-state physicist at Uppsala University in Sweden.
Celsius was a Swedish astronomer and is credited with discovering the relationship between the aurora borealis and the Earth’s magnetic field, as well as a method for determining the brightness of stars, according to the US National High Magnetic Field Laboratory.
In a presentation to the Royal Swedish Academy of Sciences in 1742, Celsius proposed a scale based on two fixed points, zero as the boiling point of water and 100 as the freezing point of water. However, after Celsius’ death in 1744, the famous Swedish taxonomist Carl Linnaeus suggested switching the fixed points, with zero indicating the freezing point of water and 100 the boiling point, and the scale was also extended to include negative numbers.
Celsius called his scale at first “Centigrade”, which derives from the Latin (Centi) meaning “hundred” and (grade), meaning degree, because there are a hundred points between freezing and boiling water. However, in 1948 an international conference on weights and measures changed the name to “Celsius” in honor of Anders Celsius, according to the US National Institute of Standards and Technology (NIST).
Temperatures in the Celsius scale can be expressed as a number of degrees followed by the symbols (℃), or simply “C”.
To compare the Celsius scale and Fahrenheit, we will find that the Celsius scale has 100 degrees between boiling and freezing of water, while the Fahrenheit scale has 180 degrees in between. This means that one Celsius degree is equal to 1.8 degrees Fahrenheit. However, at -40 degrees, both scales have the same value; -40 degrees Celsius = -40 degrees Fahrenheit.
Kelvin…an absolute measure for scientists
In 1848, the British mathematician and scientist William Thomson – also known as Lord Kelvin – proposed an absolute temperature scale, which was independent of the properties of matter such as ice or the human body.
He suggested that the range of possible temperatures in the universe far exceeds those suggested by Celsius and Fahrenheit.
According to the US National Institute of Standards and Technology, the concept of an absolute minimum temperature was not new, but Kelvin was able to put an exact number to it, zero Kelvin equal to -273.15 degrees Celsius.
Julia Churchligt, an expert in pressure and vacuum measurements at the National Institute of Science and Technology in the United States, says:Live Science(Live Science) The thermodynamic temperature differs from temperatures based on the freezing and melting points of liquids.
“Thermodynamic temperature is absolute, not relative to fixed points. It describes the amount of kinetic energy contained in the particles that make up a mass of matter, which oscillates and vibrates at near-microscopic levels.” “As the temperature decreases, the particles slow down until all motion stops at some point. This is absolute zero, which is the Kelvin scale standard.” Absolute zero occurs at −273.15 °C or 459.67 °F.
For Kelvin, absolute zero was where the thermometer should start, but for convenience he used the marks and commas in the Celsius scale as the base for his thermometer. As such, on the Kelvin scale, water freezes at 273.15 K, or zero degrees Celsius and boils at 373.15 K, or 100 degrees Celsius.
One kelvin is referred to as a unit, not a degree as on the Celsius scale, and a unit is equal to one degree on the Celsius scale.
Scientists prefer to use the Kelvin scale mainly. And in 2018, the Kelvin scale was redefined to make it more accurate, according to a research paper in the journal “Kelvin.”metrology(Metrologia), and its definition is now linked to the “Boltzmann constant” which relates temperature to the kinetic energy within a substance.
What is the best and most accurate scale?
The best scale for measuring temperatures can vary depending on the conditions, or the community you’re sharing the information with. Historically, Americans use the Fahrenheit scale for everyday life, including weather and cooking, but most countries use the Celsius scale, so it is best to use this scale while communicating internationally.
“Accuracy is not really a feature of the scale,” says Churchlegit. Instead, the accuracy of the measurement depends on the increments given by the thermometer being used, and the technique of the person using it.
“A number can be measured with arbitrary precision on any scale. But only Kelvin is based on physics, which means it is the most accurate scale.”
The Kelvin scale, which is based on the physical properties of any gas, can be precisely calibrated anywhere in the universe with appropriate equipment and a mass constant. For this reason, scientists often prefer to use the Kelvin scale in their experiments.