AN INNOVATIVE PHYSICAL MODEL TO TEACH HIDDEN CONCEPTS OF GROUNDWATER FLOW AND ITS EFFECTIVENESS AS A TEACHING TOOL

Active learning and the use of physical models to teach scientific concepts goes hand in hand. In geological sciences, students often experience difficulties applying mathematical concepts to understand hidden geological processes such as groundwater flow which occurs through pore spaces beneath the ground surface. Darcy’s law, an equation developed by a French engineer, is used to teach the concept of groundwater flow in almost every introductory geology, environmental geoscience, hydrology and hydrogeology class. Darcy’s equation contains several parameters which demonstrate the relationship between groundwater flow velocity, the hydraulic gradient causing the flow and a constant known as hydraulic conductivity (permeability) describing the ability of a geologic material to transmit water.

We created an innovative physical model (Darcy’s Column) for the purpose of teaching Darcy’s law in classes ranging from introductory (such as physical geology) to an upper level graduate class in water resources management. We also used the model to teach groundwater flow to a group of high school students. To evaluate the effectiveness of this model as a teaching tool, we asked the students several questions. In one of the questions, the students were asked if after seeing the Darcy’s Column experiment, they thought the concept of fluid flow through porous media was easier for them to understand as opposed to merely seeing a picture of the Darcy’s Column. In another question related to the application of the parameters that are used in Darcy’s equation, Q = K(dh/dl)A, where Q = discharge, K = hydraulic conductivity or permeability of the porous media, dh/dl = hydraulic gradient and A = cross sectional area, the students were asked if any or all of the parameters were easier for them to understand after using the model. They were also asked if it was easier for them to measure and quantify these parameters and understand how their dimensions (units) work. Ninety five percent of the students polled from the different levels indicated that the use of this physical model was more helpful for them to understand the concept of groundwater flow than a picture. They also overwhelmingly indicated that this model helped them in quantifying the parameters in the Darcy’s equation with better understanding.