Answer:
Celsius and Fahrenheit differ in two key ways:
1) They are measured against two different things. 0°C is the freezing point of fresh water, but 0°F was established as the freezing point of a brine made with water, salts, and ammonium.
2) The scale is different. A single degree in Fahrenheit measures 5/9 the difference in energy measured by a single degree in Celsius.
