# eli5!Why do we have different temperature measurement?

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eli5!Why do we have different temperature measurement?

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Temperature scales are set by people taking measurements and then making a scale out of those, for example celcius was made by measuring the temperature of boiling water and the temperature of freezing water and then dividing what is inbetween in 100 parts.

If you take different measurements to base your system on, like body temperature and the freezing point of salt water for example you get a different temperature scale.

Celsius was based off the boiling and freezing point of water. Fahrenheit was based off body temperature. And Kelvin was based off absolute energy, I.e 0 Kelvin is the lowest possible. God knows why people still use Fahrenheit as a weather temperature scale, Celsius makes far more sense

Almost anything can be measured in different ways. Length, time, weight, or in this case temperature. Horses are measured in hands, the pyramids were built in cubits, pounds, kilograms, on and on.

For temperature, unlike most other scales, it’s also arbitrary where we put the zero, which is why it’s so unique. Zero centimeters is obviously no length. Zero kilograms is no weight, but what is “no temperature?”

Celsius uses the freezing and boiling points of water, puts zero at freezing, and splits that range into 100 “degrees.” Fahrenheit, on the other hand, puts zero at the freezing point of a brine solution, 32 at the freezing point of water, and 180 “degrees” later the boiling point of water (212). And don’t even get me started on Kelvin.

Final result: several massively different measurement systems for a thing that’s actually very hard to quantify. Temperature is unique in that respect.

If you are talking about Fahrenheit, Celsius and Kelvin these were developed at different times and became popular at in different parts of the world and for different uses. At first we did not have a temperature scale. But this was something scientists needed as they had to measure things constantly. A big problem here is how to make a scale which allows you to calibrate your instruments. With weights and lengths you can make a calibrated physical objects that you ship to other scientists which they can calibrate their instruments by. But you can not ship a temperature.

At first Fahrenheit came up with two fairly consistent temperatures to use. He used the coldest thing he could measure which was the freezing point of a brine solution and the hottest consistent temperature he could measure which was his body temperature. The large span meant that you could calibrate instruments over a wide range of temperatures. And the Fahrenheit scale spread among scientists and through meteorologists into the general population.

Then came Celsius, another scientist. At this point the Fahrenheit scale was not the only temperature scale in use and they all had some problems. For Fahrenheit it was hard to get the brine solution cold enough that it froze and body temperatures are hard to measure and varies too much. The temperature scale named after Celsius was simpler but more accurate and easier to use as it used the freezing point and boiling point of pure water. This is conditions which are very easy to replicate in any lab, or indeed any kitchen for that matter. So it was much easier for scientists to calibrate their instruments. This soon became the standard way to calibrate instruments for all scientists. However the Fahrenheit scale were still widespread, although it is almost gone from common use now.

The Kelvin scale on the other hand was invented because the freezing point of water is rather arbitrary from a mathematical point of view. All the laws of physics that dealt with temperature ended up with this same constant to account for the Celsius scale. So to make the math easier the scientists just removed this constant and came up with the Kelvin scale. Its main advantage is that it is easier to use in physics calculations. But since most people experience temperatures closer to room temperature it is not expected to become very much used outside of the scientific communities.

Fahrenheit is how we feel temperature

Celsius is how water feels temperature

Kelvin is how atoms feel temperature