XRD ANALYSIS AND PROJECT-BASED LEARNING IN AN ENVIRONMENTAL GEOLOGY LABORATORY COURSE

The Environmental Geology course and required laboratory component are taken by 750 Georgia Southern University students each year to fulfill a core curriculum requirement in environmental science. Although many of the laboratory and field exercises are tailored to local and regional environmental issues, activities dealing with minerals and rocks involve traditional hand-sample identification. The purchase of a Rigaku MiniFlex XRD (funded by NSF DUE 0311730) has allowed us to create project-based investigations of household and construction materials to explore properties and uses of minerals.

The household materials exercise is a simple introduction to the basic theory of XRD and the identification of the mineral content of various cleaning agents (e.g., bathroom and kitchen cleaners), cosmetics, personal hygiene products, and over the counter medicine (e.g., vitamin and mineral supplements). The construction material exercise involves the analysis of old construction materials that contain asbestiform minerals and the hazards they present.

The success of these exercises was ascertained by formative and summative evaluations. A two-group, before-and-after experimental design was used to conduct the summative portion of the evaluation. One-half of the laboratory sections (randomly chosen) was taught the above-mentioned exercises in the traditional manner while the rest used the XRD. All students took a test based on questions relating to mineral resources. Both groups were measured twice: a pre-test at the beginning of the semester and a post-test after completing the exercises. The pretest did not differ significantly between the two groups whereas the post-test score for the XRD group was almost 7% higher than that of the non-XRD group. The formative evaluation provided a qualitative dimension to the evaluation process. Nearly 80% of the students reported that using the XRD increased their understanding of minerals and helped them think more critically about mineral applications. All students felt that the XRD analysis helped them in understanding the course material and they enjoyed the hands-on experience. In summary, the XRD has improved the instruction of mineral science concepts and enhanced the science experiences of those students enrolled in our Environmental Geology laboratory course.