June 15, 2014
June 15, 2014
June 18, 2014
Computing & Information Technology
24.123.1 - 24.123.13
Interactive Molecular-level Descriptions in Engineering Educational SimulationsA review of various college textbooks in engineering revealed a mixed trend towardsincluding molecular level descriptions to explain fundamental concepts and processes inthermal and fluid sciences at the introductory level. Depending on the fundamentalconcept, a macroscopic level of description is oftentimes favored in most textbooks. Thismixed trend can partially be explained by the difficulty of explaining molecular actionthrough static images in a textbook. However, recent educational research shows thatstudent learning is enhanced when concepts are described at the molecular level as anemergent process. We hypothesize that carefully designed interactive animations can beused to reinforce fundamental concepts at the microscopic level.The objective of this study was to create interactive educational simulations at themolecular level in order to illustrate fundamental concepts in thermal and fluid sciences.Our future goal is to use these simulations to test our hypothesis on enhanced studentlearning. The simulations can provide students a more complete understanding ofdynamic phenomena at the molecular level that are not readily observable. The conceptsand phenomena chosen for in this study are temperature, pressure, viscosity, friction influid, and heat transfer through conduction, convection, and thermal radiation.We use the Mathematica software and some existing simulations within the WolframDemonstrations Project to create interactive animations for our purposes. The animationsadopt major simplifications to the underlying theory to enable interactivity whileconveying the fundamentals. Students can manipulate the variables of the physicalprocesses to illustrate what effects these variables have on the system as a whole.We consider the molecular motion of matter in three phases to illustrate temperatureconcept. The animation allows students to select the phase of matter, and vary thetemperature of the matter to observe the associated response in molecular motion in eachphase separately.A majority of undergraduate textbooks in physics, fluid mechanics and thermodynamicsdescribe fluid pressure as the normal force acting on a unit surface, followed by anexplanation of how fluid pressure varies with depth. However, this basic description doesnot explain pressure in the context of an ideal gas, and it is connection to temperature atthe molecular level. To address this issue, we developed an animation where pressure isillustrated by molecules bombarding the walls of a piston cylinder device. The pistonmoves freely and its position rises during collisions with the gas molecules. Students areable to vary temperature of the system or compress the piston to investigate the responseon pressureViscosity and fluid friction is demonstrated with two simulations that are based onCouette flow. The viscosity simulation allows students to change the mass and size ofmolecules to observe the effects on fluid flow. The fluid friction simulation allowsstudent to vary the velocity profile of the flow. When molecules collide, their colorchanges briefly to highlight the frequency of collisions and therefore the shear stress.The conduction simulation allows student to vary the temperature at one side of a solid toshow how energy is conducted through a solid. The convection simulation shows fluidmolecules removing energy from solid molecules as students vary the wind speed. Theradiation simulation depicts a water molecule absorbing, reflecting, or being transparentto different wavelengths of radiation.The simulations are designed as part of a research project funded by the NSF. The projecttests the idea that student learning is enhanced if certain engineering concepts andprocesses are taught at the molecular level. The simulations will be freely available uponrequest.
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