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The nature of students' ideas about the scientific practices used by astronomers when studying objects in our Solar System is of widespread interest to discipline-based astronomy education researchers. A sample of middle-school, high-school, and college students (N = 42) in the U.S. were interviewed about how astronomers were able to learn about properties of the Solar System as a follow-up question after specific questions about the nature of the Solar System and its objects. These students often held naive ideas about the practices of astronomy, and 19% of them proposed that humans or robots have returned samples of the planets to Earth for analysis. While the college students provided more sophisticated responses to the questions than the younger students, we found that even they held naive ideas about human sample return and infrequently appealed to studying objects at a distance using telescopes. We propose that students are not receiving specific instruction that allows them to investigate the tools and practices of astronomy, which leads them to rely on their prior knowledge about science practices in other disciplines (e.g., geoscience) when queried about how scientists study the Solar System. This result implies that instruction around the limits of human and robotic spaceflight is needed to allow students to have a more scientific understanding of the practices of astronomy in studying the Solar System.

We previously proposed a hypothetical learning progression around the disciplinary core idea of the Solar System and its formation as a first step in a research program to begin to fill this gap and address questions of student learning in this domain. In this study, we evaluate the effectiveness of two dimensions within the learning progression, dynamical properties and gravity, in describing change in how student reason in the domain across the course of their 14-week astronomy unit. A sample of sixth-grade students (N = 24) were interviewed before and after instruction. We compared changes in how students explained the dynamic properties of planets and the role of gravity in the Solar System to their experiences during instruction. Our findings provide evidence for the usefulness of this learning progression in describing how students' explanations may progress, offer insight into how instruction may support that progress, and highlight the challenges in drawing conclusions on how students' explanations may progress when limitations are identified in instructional experiences. We also discuss the connection between these two construct maps but also point out what appears to be a missing element in our original definition of the learning progression: inertia.

Plate tectonics is the organizing paradigm of geosciences, but it is also conceptually complex, and students often struggle with developing a system level understanding of the earth. This article reports on research designed to create a characterization of the different levels of sophistication around plate tectonics in the form of a learning progression for middle grades (grades 6--9). A learning progression is an educational research construct that can guide curriculum, assessment, and instruction by creating a description not just of students' misunderstandings but of a sequential pattern of increasingly sophisticated and productive student conceptions. This article reports on research findings from a 7-year National Science Foundation-funded project focused on the teaching and learning of earth and space science, which engaged in hundreds of conceptual interviews with students in diverse contexts across the state of Pennsylvania. This article focuses on the implications for higher education faculty in geosciences with regard to the preparation of students, the likely alternative conceptions they may hold, and hence instructional approaches to help their ideas mature toward a normative scientific understanding.

Using a conceptual framework constructed around self-efficacy, this study explores specific recruitment programs that may contribute to the development of self-efficacy for students of color in the geosciences. This mixed methods study of geoscience education includes quantitative analysis of the Summer Experience in Earth and Mineral Science Program and qualitative analysis of the Summer Research Opportunity Program. Findings identify programmatic components that fostered self-efficacy, thus contributing to students? continued interest in careers in geoscience. This study has potential implications for higher education institutions interested in cultivating programs that attract, support, and retain students of color through various stages of the geoscience education pipeline.

This study describes the process of defining a hypothetical learning progression (LP) for astronomy around the big idea of "Solar System formation." At the most sophisticated level, students can explain how the formation process led to the current Solar System by considering how the planets formed from the collapse of a rotating cloud of gas and dust. Development of this LP was conducted in 2 phases. First, we interviewed middle school, high school, and college students (N?=?44), asking them to describe properties of the current Solar System and to explain how the Solar System was formed. Second, we interviewed 6th-grade students (N?=?24) before and after a 15-week astronomy curriculum designed around the big idea. Our analysis provides evidence for potential levels of sophistication within the hypothetical LP, while also revealing common alternative conceptions or areas of limited understanding that could form barriers to progress if not addressed by instruction. For example, many students' understanding of Solar System phenomena was limited by either alternative ideas about gravity or limited application of momentum in their explanations. Few students approached a scientific-level explanation, but their responses revealed possible stepping stones that could be built upon with appropriate instruction.

As the United States strives to achieve energy independence, students need to be literate about energy and environmental issues. In this article, the authors present a lesson about the nation's electricity resources that is part 1 of a free, comprehensive unit on coal and energy that is available online (http://tinyurl.com/coalenergyunit). The comprehensive unit, which was developed by graduate students supported by the Transforming Earth System Science Education project at Penn State University, contains inquiry-based lessons designed to deepen students' understanding of key Earth-science issues. Data on electricity-generation resources in the United States, including both renewable and nonrenewable types, are highlighted within the lesson of part 1. Part 2 of the comprehensive unit includes lessons that address more detail about coal. In both parts of the unit, students learn fundamental information about the development and use of domestic energy sources. The full lesson for part 1 is included here, but both parts of the comprehensive unit are also described. Completion of all or part of the unit will provide an interdisciplinary look at the nation's energy resources. (Contains 4 figures and 1 online resource.)

Hf-Pb-Os isotope compositions and highly siderophile element (HSE) abundance variations are used to evaluate the mantle source characteristics and possible effects of differentiation processes in lavas from western Turkey, where the eruption of Late Miocene to Quaternary OIB-type intraplate mafic alkaline lavas followed pre-Middle Miocene convergent margin-type volcanism. Concentrations of Os, Ir, and Ru (IPGE) in the OIB-type intraplate lavas decrease with fractionation for primitive melts (MgO > 10 wt%), suggesting that these elements reside predominantly in olivine and associated HSE retaining trace phases and behave compatibly during olivine-dominated fractionation. Fractional crystallization trends indicate distinctly lower bulk partition coefficients for IPGE in more evolved lavas, possibly reflecting a change in the fractionating assemblages. Pd and Re in the primitive melts display negative correlations with MgO, demonstrating moderately incompatible behavior of these elements during fractionation, while the significantly scattered variation in Pt against MgO may indicate the effects of micronuggets of a Pt-rich alloy. Os-rich alkaline primary lavas (>50 ppt Os) exhibit a limited range of .sup.187Os/.sup.188Os (0.1361-0.1404), with some xenolith-bearing lavas displaying depletions in .sup.187Os/.sup.188Os (0.1131-0.1232), suggesting slight compositional modification of primitive melts through contamination with highly depleted, Os-rich mantle lithosphere. More radiogenic Os isotope ratios (.sup.187Os/.sup.188Os > 0.1954) in the evolved lavas reflect contamination of the magmas by high.sup.187Os/.sup.188Os crustal material during shallow differentiation. The OIB-type lavas show limited variations in Hf and Pb isotopes with .sup.176Hf/.sup.177Hf = 0.282941-0.283051, .sup.206Pb/.sup.204Pb = 18.683-19.091, .sup.207Pb/.sup.204Pb = 15.579-15.646, .sup.208Pb/.sup.204Pb = 38.550-38.993; .sup.176Hf/.sup.177Hf ratios correlate negatively with .sup.208Pb*/.sup.206Pb*, suggesting the effects of similar mantle processes on the evolution of time-integrated Th/U and Lu/Hf. These lavas have distinctly higher .sup.176Hf/.sup.177Hf and lower .sup.208Pb*/.sup.206Pb* than the Early-Middle Miocene lavas of the region, which are interpreted as melts of enriched mantle with an overprint by sediment-derived subduction component. The source region for the OIB-type alkaline melts is interpreted to be a sub-lithospheric reservoir enriched in Hf and Pb isotopes with respect to depleted MORB mantle. Combined evaluation of Hf, Pb, and Os isotopes suggests that the relative enrichment in this domain is related to mixing of ancient oceanic crust with the ambient mantle through long-term plate recycling processes., Author(s): Ercan Aldanmaz[sup.1] , Megan Pickard[sup.2] [sup.7] , Thomas Meisel[sup.3] , Safak Altunkaynak[sup.4] , Kaan Sayit[sup.5] [sup.8] , Pinar Sen[sup.6] , Barry B. Hanan[sup.5] , Tanya Furman[sup.2] Author Affiliations: (1) [...]

Experiments were conducted to determine whether vibrations with frequencies in the sonic to ultrasonic range have any effect on the crystallization of basalt. One-atmosphere melting experiments were done at the QFM buffer on a sample of alkali basalt. A piezoelectric quartz crystal and a function generator were used to generate waves of 1.5 MHz and 150 kHz, and waves were propagated along the platinum quench wire to which the experimental charge was attached. Experiments were conducted at 1182 [degrees] C; at this temperature the sample was about 25% crystalline and contained olivine and plagioclase. Compared to the static control experiments, vibrated experiments produced plagioclase crystals that were less euhedral and had lower aspect ratios. Crystal size distributions for plagioclase were steeper for the vibrated experiments, with a higher population density of smaller crystals. The effect on olivine crystal size distributions was less. If the effect on plagioclase extends to lower vibrational frequencies, it is possible that this phenomenon may occur in magmas prior to eruption. The experimental technique developed to produce vibrations is potentially useful for improving homogeneity of melt and increasing likelihood of achieving mineral-melt equilibrium in partitioning experiments.