# Celsius vs Fahrenheit

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So with the Celsius temperature system zero degrees is the temperature at which water freezes and one hundred degrees is the temperature at which water boils, quite simple. Fahrenheit is a bit more complicated with 32 being freezing temperature and 212 being boiling temperature. To the best of my knowledge Fahrenheit started out with 8 being the freezing point but then the entire scale was multiplied by 4 to give it a greater range and so 32 ended up being the freezing point, although I could be wrong. Zero degrees in the Fahrenheit system doesn't really mean anything unlike zero degrees Celsius which is when water freezes.

The USA uses Fahrenheit although I believe most other countries use Celsius and supposedly Celsius is considered an all together superior system which came after Fahrenheit. I don't see the USA as ever converting to Celsius as people are used to Fahrenheit and will most likely stick with it.

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And maaaany more oddities in USA as the ounces, feet, inches, gallons, pounds, furlongs, fathoms, knots, MMDDYY, small, medium and large;  twin, queen, full, king , AM/PM, acres... They just missed to drive on the left lane 😊

Edited by Externet
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https://en.wikipedia.org/wiki/Fahrenheit

The Fahrenheit scale (/ˈfɑːrənht/ or /ˈfɛrənht/) is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736).[1][2] It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined his scale exist, but the original paper suggests the lower defining point, 0 °F, was established as the freezing temperature of a solution of brine made from a mixture of water, ice, and ammonium chloride (a salt).[3][4] The other limit established was his best estimate of the average human body temperature (set at 96 °F; about 2.6 °F less than the modern value due to a later redefinition of the scale).[3] However, he noted a middle point of 32 °F, to be set to the temperature of ice water.

Fahrenheit was born in Danzig (in the Polish-Lituanian Commonwealth)

This is one, at least, that cannot be blamed on the oddity of English and USA measurements

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Neither scale is used in Physics.
The absolute scale, in  o K, starts at the point where kinetic motion of particles is essentially zero, and only quantum mechanical zero point energy remains. The K and C scales differ by 273.15 o , such that 0 o C is equivalent to 273.15 o K.

Edited by MigL
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2 hours ago, Externet said:

And maaaany more oddities in USA as the ounces, feet, inches, gallons, pounds, furlongs, fathoms, knots, MMDDYY, small, medium and large;  twin, queen, full, king , AM/PM, acres... They just missed to drive on the left lane 😊

Australia switched to the metric system in all its forms including monetary in 1966.

I'm reminded that while the USA did not do this, they did lose a Mars Climate Orbiter, because those in charge failed to convert critical measurements from fps system to the cgs system...a costly error.

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Canada still uses both. Celsius generally for weather and fahrenheit generally for body temperature. Old habits die hard. I use both for weather and almost always Fahrenheit for body temperature. I do use Celsius more for physics unless it's thermodynamics....then I use Kelvin...same damn thing except I use what I find easier to think through...similar in some respects to picking reference frames except they are all on the same "frame" temperature wise.

I use kilometres much more than miles, but 90% of the time use inches, or feet and inches, when building something. Half my tape measures are in  feet/ inches, the other half in feet/inches on one side and metric on the other. This can be a pain at times...I can't remember ever having an all metric tape measure, despite half our drawings being metric (mm). I probably could get one special order but I lose them, and they aren't readily available.

"Side" refers to different sides on the same face, not the underside.

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4 hours ago, MigL said:

Neither scale is used in Physics.
The absolute scale, in  o K, starts at the point where kinetic motion of particles is essentially zero, and only quantum mechanical zero point energy remains. The K and C scales differ by 273.15 o , such that 0 o C is equivalent to 273.15 o K.

Whilst I don't disagree, Kelvin is not a degree scale like °C or °F.

It's also not uncommon to find physics papers talking about °C. Although the closer you get to thermodynamics the less you use °C.

In the UK, in general, older people are relatively happy with both but anyone below about 40 or 50 will be far more in the Centigrade camp, I need to look up what the freezing point of water is if I need it in °F. For almost all other measurements people are accepting of both imperial and metric. I walk in km but I drive in miles. For shorter distances I go mm, cm, inches, feet, meters. My weight is in stone but I would measure ingredients in grams.

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5 hours ago, MigL said:

Neither scale is used in Physics.
The absolute scale, in  o K, starts at the point where kinetic motion of particles is essentially zero, and only quantum mechanical zero point energy remains. The K and C scales differ by 273.15 o , such that 0 o C is equivalent to 273.15 o K.

So its the Kelvin scale that's used in Physics.

Edited by Photon Guy
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6 hours ago, OldChemE said:

Fahrenheit was born in Danzig (in the Polish-Lituanian Commonwealth)

Ha ha... I didn't see this coming. I always supposed he was an American guy.

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8 hours ago, MigL said:

Neither scale is used in Physics.
The absolute scale, in  o K, starts at the point where kinetic motion of particles is essentially zero, and only quantum mechanical zero point energy remains. The K and C scales differ by 273.15 o , such that 0 o C is equivalent to 273.15 o K.

The Kelvin scale is based on the centigrade scale, but shifted by a fixed value as MigL notes.

The original centigrade scale was based on having exactly 100 degrees between the two fixed points ie the boiling and melting point of water.
There was also another water based scale due to Romer which is only of historical interest these days.

However these temperatures depend slightly upon the conditions (pressure) adopted and more modern evaluations.

The Celsius scale is based on the modern re-evaluation.

Many constants in Science have varied slightly over the years as better measurements become available.

There is an equivalent shifting for the Farenheit scale, due to Rankine.
This is (still) used in engineering where it is then compatible with other old imeprial units.

Both the Kelvin and Rankine scales

It should be noted both the Kelvin and Rankine scales are 'absolute' not arbitrary like the others.
This means that they are meant to start at 'absolute zero'.

A final point is that the Farenheit scale has the advantage of water not freezing at zero so that most European temperatures will be positive.

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8 hours ago, beecee said:

I'm reminded that while the USA did not do this, they did lose a Mars Climate Orbiter, because those in charge failed to convert critical measurements from fps system to the cgs system...a costly error.

There were couple airplane crashes and accidents due to metric-imperial conversion errors including fatal costing people lives..

In See Also section in the article above there is list of accidents which were not so happy ending as this story..

Edited by Sensei
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“In metric, one milliliter of water occupies one cubic centimeter, weighs one gram, and requires one calorie of energy to heat up by one degree centigrade—which is 1 percent of the difference between its freezing point and its boiling point. An amount of hydrogen weighing the same amount has exactly one mole of atoms in it. Whereas in the American system, the answer to ‘How much energy does it take to boil a room-temperature gallon of water?’ is ‘Go @%\$& yourself,’ because you can’t directly relate any of those quantities.” Wild Thing by Josh Bazell.

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When you draw an outline around the one on the left, it even looks like a middle finger sticking up at you 🖕

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4 hours ago, studiot said:

There was also another water based scale due to Romer which is only of historical interest these days.

Remember dealing with the Réaumur scale in high school, the equivalent formula was dividing by 4.  But was never taught about Rankine.

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Were there attempts to propose even more natural temperature scale than the Kelvin scale? (I am not sure what would that mean, perhaps something like this: temperature increase of one unit means average particle kinetic energy increase of one joule, or one nano-joule, or one eV...)

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