world: we’re gonna use the scale where 0° is freezing and 100° is boiling.
america: cool, we’re gonna use the one that doesn’t make sense.
According to an article Fahrenheit wrote in 1724, he based his scale on two reference points of temperature. The zero point is determined by placing the thermometer in brine: he used a mixture of ice, water, and ammonium chloride, a salt. This is a frigorific mixture which automatically stabilizes its temperature at 0 °F. (A mixture of ice and water also stabilizes, either freezing or melting at 32 °F though Fahrenheit did not use this point in defining his temperature scale). The second point, 100 degrees, was the level of the liquid in the thermometer when held in the mouth or under the armpit of his wife — subsequent refinements. Fahrenheit noted that, using this scale, water boils at about 212 degrees.
I always shake my head at this “Fahrenheit scale doesn’t make sense” response. It does make sense. It’s a human-calibrated scale.
The metric system is fantastic for understanding the universe. The distances between and temperatures of the stars, the characteristics of microscopic life, anything and everything in between with exponential values (i.e., the very big and the very small, and the very precise).
But I will always believe the fahrenheit scale is better for day-to-day life. An average person will never see both ends of the celsius scale in their day-to-day life walking around. It’s never been “boiling hot” outside. Using the freezing and boiling points of water as your references makes sense for a scale concerned with scientific order. But it makes no sense for a human being.
With fahrenheit, 0 is “really damn cold out” and 100 is “really damn hot out.” 70 degrees is very comfortable, 40 degrees can be chilly to people in warmer parts of the country.
With celsius, 0 is “cold” and 100 is “dead.” On the celsius scale, 0F is -17C and 100F is 37.8C. So the temperatures the vast majority of all people on the planet will experience in their day to day lives will typically fall somewhere between -17C and 37.8C. Application of the celsius scale to the human experience seems like an afterthought to me.
So dismiss the fahrenheit scale if you must. Criticize its lack of exponents, its shaky relationship with the Kelvin scale. Sure, it isn’t perfect. But don’t say it doesn’t make sense. It definitely does.