Challenge-Based Instruction in Biotransport

An introductory physiological transport course was recently redesigned to take advantage of the benefits of challenge-based instruction. In this mode of instruction a series of specific challenges are introduced throughout the semester. The challenges are based on real problems in biotransport and are designed to motivate students to discover a solution. For example, principles of diffusion and chemical reaction can be introduced by asking why cells are so small. Many important concepts in heat transfer can be discovered by asking students to play the role of a consultant in a murder trial in which the time of death needs to be estimated. Newtonian and non-Newtonian fluid mechanics can be introduced by asking how bacteria and other inspired contaminants are cleared from the respiratory system. In general, students will not have sufficient knowledge to solve the challenge as initially presented. They must consult several resources to help them understand which conservation principles apply, which constitutive relationships are appropriate, and which parameters are most important. Students are then asked to use this new information to develop a model that is appropriate for the challenge. They start this while still in the classroom so they can get help from their classmates and from the instructor. In developing a model from first principles for each case, they become familiar with the process, learn when to use a microscopic versus macroscopic balance, and should better appreciate the origins and limitations of generalized equations used to describe transport phenomena, such as the Navier-Stokes equation. Since the challenge-driven method puts students in the position where they need to determine which parts of the taxonomy are relevant to the challenge, it is hoped that this approach will better prepare students for the workplace and for life-long learning.