Discover the Reason Behind Adding 32 to the Formula for Converting °C to °F

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SUMMARY

The formula for converting Celsius to Fahrenheit incorporates the addition of 32 due to historical definitions of temperature scales. The Fahrenheit scale was originally defined such that 0°F represented the freezing point of brine, while 32°F was set as the freezing point of water. This adjustment was made in 1776, aligning 32°F with 0°C and 212°F with 100°C. The conversion ratio of 9/5 (or 180/100) reflects the difference in scale increments between Celsius and Fahrenheit.

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  • Understanding of temperature scales, specifically Celsius and Fahrenheit
  • Basic knowledge of historical scientific measurements
  • Familiarity with the concept of freezing points in different substances
  • Awareness of the significance of temperature in maritime contexts
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  • Research the historical development of temperature scales, focusing on Daniel Gabriel Fahrenheit
  • Explore the significance of freezing points for various substances, including seawater
  • Learn about the impact of temperature measurement on maritime navigation
  • Investigate the mathematical principles behind temperature conversions
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Students of physics, historians of science, and anyone interested in the practical applications of temperature measurement in everyday life and maritime navigation.

parshyaa
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How we got this formula i know that the ratio of scale difference is 180/100 =9/5 but why to add 32, is it because °F at 0°c is + 32
 
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Yes. Plug in a few numbers and you'll see.
 
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parshyaa said:
How we got this formula i know that the ratio of scale difference is 180/100 =9/5 but why to add 32, is it because °F at 0°c is + 32
The 0 was moved to be the freezing point of water. Here is some info:

http://www.todayifoundout.com/index.php/2014/12/fahrenheit-scale-isnt-arbitrary-seems/

(interestingly, originally the freezing point of water was 100°C, and the boiling point was 0°C, but Carl Linnaeus made that modification- Good read)
 
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I'm not sure how clear it is in the references, but for seafaring nations like Britain and Denmark, the freezing temperature of salt water is very significant. So setting the 0 of the Fahrenheit scale at that point makes sense. Maritime issues drove the development of clocks, thermometers, etc.
 
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upload_2016-12-23_19-53-26.png
 
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The other well-known conversion method, based on the -40° coincidence of the two scales is, I think, easier to remember. The fact that I no longer remember it is utterly irrelevant.
 
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FactChecker said:
I'm not sure how clear it is in the references, but for seafaring nations like Britain and Denmark, the freezing temperature of salt water is very significant. So setting the 0 of the Fahrenheit scale at that point makes sense. Maritime issues drove the development of clocks, thermometers, etc.

I fortified myself to argue with you with the aid of Google, which asserts that seawater freezes at 28.4°F. I seem to remember that Fahrenheit produced the lowest temperature possible to him in the day in his laboratory to get to his zero.
 
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David J Wilson said:
I fortified myself to argue with you with the aid of Google, which asserts that seawater freezes at 28.4°F. I seem to remember that Fahrenheit produced the lowest temperature possible to him in the day in his laboratory to get to his zero.
I am certainly not an expert in the history of this. I have seen it said a few times that 0°F is the freezing point of brine. (This reference says that 0°F was the lowest temperature he could get reliably by freezing brine. https://en.wikipedia.org/wiki/Brine . That makes sense to me.) I might have seen it explained as important for sailing, I don't remember. Maybe I just erroneously jumped to that conclusion. Certainly he would have wanted to include the temperature of freezing sea water in his temperature range.
 
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Is there an explanation as to why the two scales match up so nicely? The defined points are rather arbitrarily chosen.

BoB
 
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rbelli1 said:
Is there an explanation as to why the two scales match up so nicely? The defined points are rather arbitrarily chosen.

It is because the original definition of Fahrenheit was replaced in 1776 with one where 32 °F is 0 °C and 212 °F is 100 °C.
 
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