September 2005 Journal of Geoscience Education

Contemporary science education research emphasizes the importance of considering students pre-instructional beliefs when designing effective, learner-centered instructional strategies. When scientists teach about dating geological events, most often the concepts of radioactive decay and half-life are presented. However, the research base on student understanding of radiation and radioactivity is currently quite limited. The principal research question used to focus this investigation asked: What are the common difficulties that students experience when trying to learn about radiation and radioactivity? Our research illustrates that students bring to the classroom many inaccurate ideas and reasoning difficulties on the topics of ionizing radiation, radioactivity, and radioactive decay that are well-poised to interfere with students' understanding of how half-life is used to determine geologic time. To uncover the range and frequency of the dominant student beliefs, we performed individual demonstration interviews and administered open-response and multiple-choice conceptual tests to students from a wide-range of science backgrounds. Our results show that students are often unable to differentiate between the ideas of irradiation and contamination, and that many of these students' reasoning difficulties about radioactive decay and half-life stem from their inaccurate mental models regarding the atom.

The complex nature of climate change science poses spe-cial challenges for educators. Learners come to the classroom with prior knowledge on the topic, which serves as a foundation for further knowledge building, but can also pose barriers to conceptual change. Learners have existing mental models that may limit their perception and processing of con flicting information and prevent adoption of scientific conceptions. Instructional strategies that attempt conceptual change by simply provoking cognitive conflict have had limited success due to the importance of epistemological beliefs and motivation to the conceptual change process. The Mock Environment Summit course uses role-playing, argumentation and discussion to heighten epistemological awareness and motivation and thereby facilitate conceptual change. The pre/post-course concept map evaluation of students' knowledge about the science of global climate change reported here shows evidence of significant learning and conceptual change. Our study also provides useful information about gaps in knowledge and the types of misconceptions students are likely to have about this topic. Insight gained from this assessment study can be used to tailor the curriculum and enhance student progress towards more scientific conceptions of the problem.

This study explored junior high school students' perceptions of the water cycle. The study sample included 1,000 junior high school students (7th-9th grades) from six urban schools, in Israel. The data collection was based on a series of quantitative and qualitative research tools that were specifically developed for this study.

The findings indicated that the students understand various hydro-bio-geological processes, but most of them lack the dynamic, cyclic, and systemic perceptions of the system. Moreover, they possessed an incomplete picture of the water cycle including many preconceptions and misconceptions about it. Most of the sample population studied were aware of the atmospheric part of the water cycle, but ignored its groundwater part. Moreover, those who included part of the underground system in the water cycle perceived the underground water as static, sub-surface lakes.

It is suggested that the findings reflect the traditional disciplinary approach of the dealing with subject of water in the science curricula. This study also implies the need for further research about the cognitive abilities of junior high students to deal with cyclic-systems thinking, and the need to explore activities that might develop or stimulate such abilities.

We surveyed three groups of students regarding their ideas about the structure, scale, and perceived importance of groundwater. The quantitative methods employed in this study incorporated simple descriptive statistics of the six multiple-choice item responses. The results of this study indicate that many people hold inappropriate conceptions of hydrogeologic principles. They describe groundwater storage using multiple structures other than pores and cracks. Participant responses regarding the size ranges of groundwater storage structures show that students possess a wide range of ideas concerning scale. Many participants selected sizes of the groundwater structures that mirrored the surface analogs, however, some students applied scales on the order of houses and skyscrapers to typical pore and crack structures. The mental models erected according to the frameworks of these alternative scale conceptions are likely to be inappropriate and could detrimentally impact the appropriate mental visualization of other associated groundwater principles. To effectively address students' alternative groundwater conceptions teachers must pay particular attention to issues of scale, as well as the application of those conceptions to individually and socially relevant questions.

The watershed concept is important in many areas of geology and environmental science, and the purpose of this study was to investigate students' ideas about watersheds and how these ideas change across grade level. A total of 95 students were sampled: 28 sixth graders, 25 seventh graders, 22 eight graders, and 23 ninth graders. To elicit students' ideas about watersheds a task was developed that required students to draw a picture of a watershed and explain their drawing. In general, students understand a watershed from a very limited scientific perspective. For sixth and some seventh grade students a watershed is a water storage facility or a facility that supplies water. Eighth and ninth grade students' ideas about a watershed focused on a mountainous stream. Older students also incorporated the hydrologic cycle, but rarely represented linkages between land and watercourses. For all students, humans do not appear to be a part of a watershed, but separate from it. The implications of these findings are also explored.

This study explored junior high school students' understanding of essential concepts of scientific thinking "observation", "hypothesis" and "conclusion" and the effect of the learning of the program "The Rock Cycle" on the development of such understanding. The study sample consisted of 582 students of the 7th and 8th grade, who learned in 21 classes, with 14 teachers from 8 schools in Israel. The data collection was based on a quantitative research tool that was specifically developed for this study and qualitative tools such as observations and interviews.

The findings indicated that the students have considerable difficulties in understanding the basic concepts underlying the scientific inquiry, and that the "The Rock Cycle" has a potential to develop such understanding. An unexpected gender difference was found. Girls outperformed boys in scientific thinking, both in the pre and the post tests. The unique character of geoscience methodology, together with structuredinquiry and metacognitive activities, served as an appropriate framework for students to develop basic scientific thinking. The co-interpretation of quantitative and qualitative analysis indicated that the type of teacher (openness to innovative methods, enthusiasm and scientific background) was a crucial factor in students' ability to exploit the potential of "The Rock Cycle".

Assessment of learning in entry-level college science courses is of interest to a wide variety of faculty, administrators, and policy-makers. The question of student preparedness for college instruction, as well as the effect of instruction on student ideas, has prompted a wide range of qualitative and quantitative studies across disciplines. In the geosciences, faculty are just beginning to become aware of the importance of conceptual change in instruction. The development of the Geoscience Concept Inventory (GCI) and application to the study of learning in entry-level geoscience courses provides a common framework from which faculty can evaluate learning and teaching effectiveness. In a study of 43 courses and 2500 students, we find that students are entering geoscience courses with alternative conceptions (sometimes called "misconceptions"), and in many cases are leaving the classroom with these alternative ideas intact. Comparison of pre- and post-test results show that students with the lowest pre-test scores show the most improvement, whereas those with higher pre-test scores show little, if any, improvement. We also find no relationship between self-reported teaching style and learning as measured by the GCI, suggesting significant research needs to be done to evaluate teaching effectiveness in geoscience classrooms.

Although spatial ability is related to success in the sciences, relatively little research has considered the relationship of spatial abilities with common misconceptions and broader conceptual difficulties in the Earth sciences. Spatial thinking and abilities have not commonly been directly addressed in traditional education. In this study, I found moderately significant positive correlations between scores on the ESC, a new test of Earth science conceptual understanding, and scores on each of three types, or factors, of spatial ability in university undergraduate non-science majors. Types of spatial ability tested included mental rotation, spatial perception, and spatial visualization. I found mental rotation to be the best predictor of ESC scores of the variables tested. Results suggest that an opportunity may exist to improve Earth science conceptual understanding by focusing on spatial abilities or the spatial aspects of concepts.

A model-based, conceptual change approach to teaching was found to improve student understanding of earth structure in a large (100+ student) inquiry-based, general education setting. Results from paired pre- and post-instruction sketches indicated that 19% (n = 18/97) of the students began the class with naThe 60% Relative Depth Rule for Stream Velocity
H. Len Vacher, University of South Florida