Zero Fahrenheit is not completely arbitrary; it is based on an established reference point, but it does not have the same physical significance as the zero points of the Kelvin and Celsius scales.
The Fahrenheit scale was developed by the Polish-German physicist Daniel Gabriel Fahrenheit in the early 18th century. He established his scale based on a combination of a few arbitrary reference points. The zero point on the Fahrenheit scale was determined by Fahrenheit as the lowest temperature he could create in his laboratory using a specific mixture of ice, water, and ammonium chloride. This temperature was later redefined as 0°F.
Unlike the Kelvin and Celsius scales, which have absolute zero and the freezing point of water as their reference points, respectively, Fahrenheit's scale lacks a universal physical basis. The freezing point of water is marked at 32°F on the Fahrenheit scale, and the boiling point of water is set at 212°F under normal atmospheric conditions.
Since the Fahrenheit scale is not based on any inherent physical properties of matter, its zero point does not represent a fundamental state or a natural reference point. It is simply a value established by Fahrenheit based on his own experimental observations.
It's worth noting that the Fahrenheit scale is primarily used in the United States and a few other countries. The Celsius (or Centigrade) scale, which is based on the freezing and boiling points of water, is used as the standard temperature scale in most parts of the world. The Kelvin scale is primarily used in scientific contexts, particularly in physics and other fields where absolute temperatures are relevant.