  In this paper an alternative way of conducting the physics laboratory
exercise for determining the adiabatic index of air using the Clement --
Desormes method is proposed.
  The process of isochoric cooling of air has been studied in terms of the
dependence of pressure on time, and hence temperature on time, since it is
proportional to pressure at a constant volume and mass of air. A theoretical
model of the considered process was also made. The experimental results were
processed statistically. The coefficient of determination $R^2$ and the F-test
statistic were calculated and their values indicate a very good agreement
between theory and experiment. The analysis of the residuals, however, implies
that the model could be further improved through the inclusion of higher order
terms.
