Fahrenheit scale

Daniel Gabriel Fahrenheit created his temperature scale in 1724, choosing reference points that seemed natural to him: zero at the coldest temperature he could reliably produce in his Danzig laboratory (a mixture of ice, water, and ammonium chloride), and 96 at human body temperature—later revised when more precise measurements showed average body temperature closer to 98.6°.

Fahrenheit's scale reflected practical considerations. He wanted zero to be a reachable benchmark, not a theoretical absolute. His choice of 96 for body temperature (later 98.6) created conveniently divisible intervals for medical applications. The resulting scale placed water's freezing point at 32° and boiling point at 212°—awkward numbers that become routine through familiarity.

The scale succeeded because of Fahrenheit's thermometers, not his number choices. His mercury instruments were the most precise available, maintaining consistency that other makers could not match. When scientists needed accurate temperature readings, they bought Fahrenheit thermometers and adopted his scale by default. The numbers were incidental; the precision was essential.

Celsius's scale, introduced in 1742, offered mathematical elegance: 0° to 100° for water's liquid range. Scientific applications gradually shifted toward Celsius; everyday usage split geographically. The metric system's spread carried Celsius with it; countries using imperial measures retained Fahrenheit for weather and cooking.

The United States remains the major holdout, using Fahrenheit for everyday purposes while science education teaches both. The scale persists through inertia rather than advantage—Americans understand 70°F means pleasant weather, and that intuition is hard to replace with 21°C.

Fahrenheit demonstrated that scales become conventions. Once established, they persist even when alternatives offer logical improvements. The arbitrary choices of an 18th-century instrument maker still structure how Americans talk about weather.