Abstract:

This contribution presents an innovative educational approach for teaching Thermal Engineering through a multilingual open educational resource designed to support experimental learning. The material is structured in three languages: Spanish, English, and French, facilitating accessibility for diverse student groups and encouraging international collaboration in engineering education. The proposal is centred on an experimental methodology that guides students in exploring the thermal equation of state of fluids by using a laboratory apparatus capable of measuring Pressure-Volume-Temperature (PVT) relationships. The learning experience places students in a structured sequence of experiments in which temperature and volume are selected as independent variables, while pressure becomes the resulting measurable property. Through this process, learners observe fundamental thermodynamic behaviours such as the superheated vapour region, the initial condensation point, the liquid-vapour equilibrium zone, the saturated liquid state, and the compressed liquid region. The experimental workflow also enables students to identify saturation lines and analyse the emergence of the critical point under specific conditions. The pedagogical innovation lies in linking theoretical content with directly observable physical phenomena through guided experimentation and the visual material provided in the book, which supports interpretation of PVT curves and phase transitions. Students are encouraged to reason about density and specific volume, relate observations to thermodynamic principles, and develop scientific competencies such as detailed observation, hypothesis testing, and analysis of empirical data. The resource has been implemented in undergraduate engineering courses, where students completed the experimental protocol, recorded measurements, and interpreted the resulting diagrams. Initial evidence indicates a substantial improvement in the understanding of phase transitions and of the limitations of idealised models. Students particularly valued the opportunity to contrast theoretical concepts with real experimental behaviour, recognising the relevance of hands-on practice in engineering problem-solving.

Keywords:

Open Educational Resources (OER), Experimental Learning, Thermodynamics Engineering, Thermal Equation of State.