Experimental data have served two critical roles in applied thermodynamics: (1) by guiding the optimum structure of engineering correlations; and (2) by providing the factual basis to evaluate competing processes, to optimize designs and ultimately to guarantee plant performance. This presentation provides a historical perspective on the role of experimental data in guiding applied-thermodynamic correlations over the past two centuries, and also highlights the contribution experimental data are making to present-day process technology.

John O'Connell has taught me many things over the past 30+ years, and perhaps the foremost of these is to pay careful attention to and to learn from the experimental data.