Fahrenheit was not an entirely arbitrary choice: it was defined based on two points of reference that could be measured at the time: the freezing temperature of an ammonium chloride brine is used as 0, and the best estimate for the average human body temperature is set at 96.
Over time, as the freezing point and boiling point of water at sea level atmospheric pressure proves to be more accurate reference points, the Fahrenheit scale was adjusted to provide exact conversion to Celsius.
Are you telling me they were able to measure those things, but not the boiling and freezing point of water?
Sure, let me just whip up that ammonium chloride mixture and travel somewhere where I can get it close to freezing so I can know the zero reference of that scale. What, did the just carry that NH₄Cl around for convenience?
Fahrenheit was proposed in 1724, Celsius dates back to 1742, so there wasn’t that much time between the two.
Boiling point of water varies based on atmospheric pressure, water boils at a lower temperature high up in the mountains, for example, which could be why the estimated human body temperature is set as a standard, because it is consistent to reproduce as long as there are people around.
The freezing point of water is not affected by atmospheric pressure, however, it is affected by dissolved material in the water. Using a saturate solution of a salt would establish that consistency as well as lower the freezing point to create a bigger temperature range.
A bit of mistake I made there, I should say that the freezing point is relatively unaffected by pressure compared to the boiling point, and the amount of dissolved impurities are going to have a greater effect.
Fahrenheit was not an entirely arbitrary choice: it was defined based on two points of reference that could be measured at the time: the freezing temperature of an ammonium chloride brine is used as 0, and the best estimate for the average human body temperature is set at 96.
Over time, as the freezing point and boiling point of water at sea level atmospheric pressure proves to be more accurate reference points, the Fahrenheit scale was adjusted to provide exact conversion to Celsius.
Are you telling me they were able to measure those things, but not the boiling and freezing point of water?
Sure, let me just whip up that ammonium chloride mixture and travel somewhere where I can get it close to freezing so I can know the zero reference of that scale. What, did the just carry that NH₄Cl around for convenience?
Fahrenheit was proposed in 1724, Celsius dates back to 1742, so there wasn’t that much time between the two.
Boiling point of water varies based on atmospheric pressure, water boils at a lower temperature high up in the mountains, for example, which could be why the estimated human body temperature is set as a standard, because it is consistent to reproduce as long as there are people around.
The freezing point of water is not affected by atmospheric pressure, however, it is affected by dissolved material in the water. Using a saturate solution of a salt would establish that consistency as well as lower the freezing point to create a bigger temperature range.
Does ammonium chloride brine not freeze at different pressures?
A bit of mistake I made there, I should say that the freezing point is relatively unaffected by pressure compared to the boiling point, and the amount of dissolved impurities are going to have a greater effect.
…96? How is 96 a point of reference when you are making a scale from scratch?
I think it’s because 96 is divisible by 3.
96 is divisible by 1, 2, 3, 4, 6, and 8
100 is divisible by 5, so what’s your point?
Easier to subdivide a physically measured scale when the reverence is divisible by multiple values to choose from…