PX284 - C4 - measuring entropy

in thermodynamics, entropy cannot be measured directly, but the change in entropy can be measured using the heat capacity
for a reversible process at constant volume, using the first law of thermodynamics:

\begin{matrix} d U = T d S = C_{V} d T \\ ⟹ Δ S = \int_{T_{1}}^{T_{2}} \frac{C_{V}}{T} d T \end{matrix}