There are three temperature scales. Most people are familiar with either the
Fahrenheit or the Celsius scales, with temperatures measured in degrees
Fahrenheit (º F) or degrees Celsius (º C) respectively. On the Fahrenheit scale,
water freezes at a temperature of 32º Fahrenheit and boils at 212º F. Absolute
zero on this scale is not at 0º Fahrenheit, but rather at -459º Fahrenheit. The
Celsius scale sets the freezing point of water at 0º Celsius and the boiling
point at 100º Celsius. On the Celsius scale, absolute zero corresponds to a
temperature of -273º Celsius.
Scientists - especially those who study what
happens to things when they become very, very cold - commonly use the Kelvin
scale, with temperatures measured in Kelvin (K). This scale uses the same
temperature steps as the Celsius scale, but is shifted downward. On this scale,
water freezes at 273 K and boils at 373 K. Only on the Kelvin temperature scale
does absolute zero actually fall at 0 K.
