The Zeroth Law and the Ideal-Gas Temperature Scale

Control console

Fill the bulb to a chosen pressure at the triple point of water, then read the pressure with the bulb in the bath of interest.

Working gas

The gas must not condense at the bath temperature.

Filling pressure at the triple point

kPa

Lower filling pressures give a smaller non-ideality correction but a noisier reading.

Thermal bath

pwrmeasfault

Select the working gas and the filling pressure. The apparatus automatically records the pressure P_tp at the triple point of water when it is filled.
Select the bath and take the reading. The mercury is always returned to the fiducial mark, so the volume is constant.
Repeat for at least five filling pressures spanning the available range, keeping the gas and bath fixed.
Plot the apparent temperature 273.16 K x P/P_tp against P_tp and extrapolate the straight line to P_tp = 0.
Repeat the whole sequence for at least two more gases and confirm that the intercepts agree.

standby

No readings on this channel yet. Set the controls and press Read manometer.

A fresh page. Take your first reading and it will be entered here.

Take at least one reading to plot.