Visualizing the Kinetic Theory of Gases by Student-created Computer Programs

Abstract

Christian Steinmann has an engineer degree in mathematics from the Technical University Graz, where he focused on software quality and software development process assessment and improvement. He is manager of HM&S IT-Consulting and provides services for SPiCE/ISO 15504 and CMMI for development as a SEI-certified instructor. He performed more than 100 process assessments in software development departments for different companies in the finance, insurance, research, automotive, and automation sector. Currently, his main occupation is a consulting project for process improvement for safety related embedded software development for an automobile manufacturer. On Fridays, he is teaching computer science introductory and programming courses at Joanneum University of Applied Sciences in Graz, Austria.c American Society for Engineering Education, 2017 Visualizing the kinetic theory of gases by student-created computer programsMost introductory thermodynamics courses use the historical derivation of thermodynamics that relies on macroscopic properties of substances. Classical thermodynamics is a phenomenological theory; it studies the properties of a thermodynamic system without going into the mechanism of the observed phenomena. The thermodynamic state of a system is given by a limited number of thermodynamic variables, like the volume of the system and its temperature, and studies the dependence of quantities like pressure, energy, and entropy on these variables.On the other hand, the kinetic theory of gases attempts to describe the macroscopic properties in terms of a microscopic picture of the gas as a collection of a large number of particles in motion. The particles collide elastically with each other and with the walls of the container, and the pressure exerted by the gas is due to the elastic collisions of the particles with the walls. In equilibrium, this pressure is equal throughout the gas, and the kinetic theory predicts that the pressure is proportional to the number of particles per unit volume and to their average kinetic energy. By identifying the absolute temperature as the average kinetic energy of the particles, Boyle's pressure-volume law and Amontons' pressure-temperature law can be derived. Thus, the application of the laws of mechanics to the microscopic constituents of a macroscopic system predicts, with the aid of statistical techniques, the behavior of the system in agreement with experimental observation.Computer programs that simulate and visualize the kinetic theory of gases within the hard sphere model have been developed within the framework of undergraduate student projects. The C# simulations use a freely selectable number of particles to simulate the molecules of an ideal gas in a two-dimensional container. The particles are considered as small hard spheres and collide with each other and with the walls of the container. At impact, they exchange momentum and energy according to the rules of elastic collision. One wall is replaced by a piston that is loaded either by gravity or by a s...