Student conceptual understanding and conceptual change is an active area of research in many science disciplines. In the geosciences, alternative conceptions held by students, particularly college students, are not well documented or understood. To further this body of research, students enrolled in introductory science courses at four institutions completed 265 open-ended questionnaires and participated in 105 interviews. Data were collected at a small private university, two large state schools, and one small public liberal arts college. Students were probed on a variety of topics related to the Earth's crust and interior, as well as geologic time. Analysis of questionnaire and interview responses indicates that students hold a number of non-scientific ideas about the Earth. Additionally, students apply a range of ontological categories to geologic phenomena, with significant implications for teaching geosciences from a systems perspective.
The study of what students believe about science, how ideas about science can develop or change, and why some ideas are prevalent throughout society has been an active focus of research for many years (Gilbert and Watts, 1983; Driver et al., 1985; Lawson et al., 2000). The study of conceptual understanding and conceptual change in the Earth Sciences, however, has typically been limited to issues related to space science or the environment. Additionally, the few existing studies are almost exclusively limited to K-12 students, with very little examination of ideas held by college students. We report here on a multi-institution study of the ideas held by college students about a variety of geoscience topics. This research is part of a larger project aimed at developing an assessment instrument for entry-level geoscience courses (Libarkin et al., 2002).
We have chosen to focus our initial efforts on three aspects of geoscience: Earth's crust, Earth's interior, and geologic time. Findings reported here are limited to topics covered in questionnaires administered during the 2001-2002 academic year and student interviews conducted during Spring 2002, although study of additional topics is ongoing. We find that a range of student ideas exists, and many of these are common across institutions, regardless or the demographics of the student population. Additionally, students' views of the world around them can be categorized ontologically (e.g. Chi and Slotta, 1993; Chi, 1997), and we have found similarities in ontological perspectives within the entire population studied. The term "ontology" refers to a hierarchical structuring of knowledge, and allows us to describe the ways in which people understand geologic processes (Table 1). We separate our discussion into two components: a reporting of existing student ideas, and an analysis of the implications of student ontologies on current reform efforts.
Student Ideas - Student ideas about the Earth that have not previously been reported are documented here. A few of the most prevalent ideas are discussed in detail, and some suggestions for their origin and ties to existing literature are reported. Additionally, commonalities in non-scientific ideas that exist across institutions, as well as differences, are considered. For instance, most students at all four institutions believed some form of life existed when the Earth first formed as a planet. However, the form that this life took varied significantly across institutions. Similarly, most students subdivided the Earth's interior into spherical layers, although few students were able to explain the reasons behind these divisions.
Student Ontologies - The focus of Earth Science education at both the K-12 and collegiate levels has shifted over the past decade from a focus on sub-disciplines to a focus on the Earth as an integrated system. National organizations have published a number of documents encouraging faculty to teach undergraduates from an Earth Systems Science perspective (Ireton et al. …