A note on good practice We write
T = 0, not T = 0 K for the zero
temperature on the thermodynamic
temperature scale. This scale is
absolute, and the lowest temperature
is 0 regardless of the size of the
divisions on the scale (just as we write
p = 0 for zero pressure, regardless of
the size of the units we adopt, such as
bar or pascal). However, we write 0°C
because the Celsius scale is not
absolute.