THE BONDING PROPERTIES OF WATER: AN ASSESSMENT OF STUDENT UNDERSTANDING

Fundamental to most concepts explored in the geosciences is an understanding of the physical properties of water that result from the structure and interactions of its molecules. The purpose of this study was to assess the ability of students in a general education environmental geology class at a regionally accredited university in southwest Florida to demonstrate their understanding of the properties of water using diagrammatic and textual representations. The assessment, which was administered by two different instructors over the course of three semesters, asked students to explain the chemical properties within a water molecule and between water molecules and to illustrate how the adsorbent properties of water affect soils. This assessment was administered as a pre-test at the beginning of the semester and again as a post-test later in the semester following instruction on water and its interaction within the geosphere. In addition, magnetic water molecule models were used by students to explore the dipolar nature of the water molecule following the pre-test. Results from this study indicate that students entered the class with little prior knowledge of the properties of water and that learning gains on this subject were retained throughout the semester. Differences in retention were observed between the courses which might be explained by the timing of the post-test in relationship to the delivery of the content. Based on these results, the inclusion of instruction on the bonding properties of water in introductory geology courses is important to ensure that students have the necessary understanding of this critical concept.