Work in Progress - Group Laboratory Experiment During Lecture in an Undergraduate Fluid Dynamics Class: Increasing Student Learning and Communication Skills

摘要

Laboratory classes in engineering often occur toward the end of curriculum, excluding their benefits from the core class while it is being taught. Instead of a full laboratory, presentations and in-class demonstrations are often used to bring the concepts "to life." This work presents an on-going effort to integrate a simple, group-based laboratory into an undergraduate chemical engineering fluid dynamics course. This implementation method was based on previous work where a brief demo was done in class at the end of the semester in Fall 2016. Student feedback via surveys indicated they needed more time, smaller groups, more preparation, and the lab to be introduced closer to when the topic was learned in class. Those improvements were all made here. The lab occurred during one 75-minute course period. The concept used milli-fluidic devices fabricated in-house with a gravity driven flow. A conical funnel and tubing were used to supply water flow driven via a height difference through the milli-fluidic devices. The devices had various channel designs including a straight channel, one with 14 90° bends, and one with 22 90° bends to study the equivalent length (frictional increase) of the bends. Groups of three (from 45 total students) were given a brief write-up in advance of the class period with a schematic of the setup, relating the equipment to the Mechanical Energy Balance, an equation they had learned in the previous weeks. During the course period, the groups had access to the various milli-fluidic devices, tubing, hose-clamps, collection jars, calipers, and a scale. Their task was to find the equivalent length of a 90° bend, based on their collected experimental data. They designed their own experiment during the class period to accomplish this task. Most tubing was cut to provide a water column (driving force) between 1.5 and 4 ft. Students collected water as it drained while recording the time, and the mass of water was determined with the scale. With this mass flow rate, students could analyze the system for the unknown equivalent lengths. A week after the in-class work, a question based on this experiment was included in Exam 1. Further, a brief report was required of each group 12 days after the in-class activity, worth 5% of the course grade. A survey in the Fall term of 2017 assessed students' thoughts on this format versus a traditional lecture, and if they believe this helped their understanding. Based on questions asked of the instructor during the laboratory day, it appears many students gained insight by being able to generate numbers via an experiment related to equations previously applied only to textbook-type problems.