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[1] We measured the rate of melt extraction from partially molten olivine aggregates into a porous reservoir as a function of melt content (f), melt viscosity, grain size, and pressure difference. Samples were prepared using mixtures of olivine and either lithium silicate, MORB glass, or albite glass to obtain a range in melt viscosities. Experiments were conducted at 1473 K with a confining pressure (P c ) of 300 MPa. The melt pressure (P m ) was controlled using a pore fluid actuator to adjust the pressure of Ar gas (P f ) in contact with the melt. Compaction rates decrease with decreasing f and increase linearly with the pressure difference DP = P c À P f . For the two lower viscosity melts, no gradients in melt fraction were observed in samples with melt fractions as low as 0.03. By contrast, the melt fraction increases with distance away from the reservoir for samples with the highest viscosity albitic melt. These observations indicate that the compaction length for the lower viscosity melt experiments (i.e., olivine + MORB and olivine + Lisilicate) was greater than the sample length. However, the compaction rates of these samples were limited by two different processes. Melt transport is relatively easy in the coarse-grained Li-silicate samples where melt viscosity is lower. In this case, melt extraction is limited by viscous compaction of the solid matrix. In the olivine + MORB samples, the fine grain size and higher melt viscosity inhibits melt transport and limits extraction rates. The olivine + MORB data constrain the permeability of the partially molten samples. Permeability is proportional to f 3 for melt fractions from 0.05 to 0.35. In addition, assuming that permeability scales with the square of the grain size, the magnitude of the permeability compares very well with that measured for Fontainebleau sandstone and fine-grained quartz aggregates with similar pore-space topology. Calculations of the compaction length using previously published continuum models agree with the estimates derived from the experiments.

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This study analyzed quantitative and qualitative data from classroom observations combined with instructor survey results to characterize the application of reformed teaching practices in undergraduate geoscience classes in the United States. Trained observers used the Reformed Teaching Observation Protocol (RTOP) to score 204 geoscience classes. Observed faculty represent a diversity of institutions, teaching rank, and years of experience. Classrooms observed included introductory and upper-level undergraduate courses that ranged in size from 6 to 275 students. Total RTOP scores do not correlate with class size, class level, institution type, instructor gender, instructor rank, or years of teaching experience. Classroom instruction was separated into three categories based on total RTOP scores: Teacher Centered (≤30), Transitional (31-49), or Student Centered (≥50). Statistical analyses of RTOP subscales and individual item scores are used to identify the instructional practices that are characteristic of each category. Instructor survey responses and qualitative classroom observations provide additional details about instructional practices common within each instructional category. Results of these analyses provide a coherent picture of instructional strategies used in geoscience classrooms. Instruction in the most Student Centered classrooms differs from that in Transitional and Teacher Centered classrooms in at least one of three ways. Student Centered classes are more likely to include (1) students engaged in class activities with one another; (2) activities in which instructors assess student learning and adjust lessons accordingly; and (3) opportunities for students to answer and pose questions that determine the focus of a lesson.

Background: The efficacy of active learning within STEM education is clear, and many institutions are working to help faculty adopt evidence-based instructional practices (EBIPs) which can promote active learning. In order to know the current status of our campus regarding these goals, measures of current instructional climate and the adoption of evidence-based instructional practices (EBIPs) are desired. Results: Using a campus-wide online survey approach with remuneration for faculty participants, the 28-item current instructional climate survey (CICS) and the 6-item EBIP adoption scale were developed. When CICS and EBIP adoption scale outcomes are compared, patterns emerge which reflect the climate, conditions, and personal characteristics of faculty at different stages of EBIP adoption. Conclusions: Although not causal relationships, understanding both climate and personal change characteristics can be helpful to campus change agents in assessing the current STEM landscape of faculty practices.

We compared 236 geoscience instructors' histories of professional development (PD) participation with classroom observations using the Reformed Teaching Observation Protocol (RTOP) that describe undergraduate classes as Student-Centered (score ≥ 50), Transitional (score 31-49) or Teacher-Centered (score ≤ 30). Instructors who attended PD (n = 111) have higher average RTOP scores (44.5 vs. 34.2) and are more frequently observed teaching Student-Centered classes (33% vs. 13%) than instructors with no PD (p < 0.001). Instructors who attended PD that is topically-aligned with content taught during the classroom observation are likely to have RTOP scores that are higher by 13.5 points (p < 0.0001), and are 5.6 times more likely to teach a Student-Centered class than instructors without topically-aligned PD. Comparable odds of teaching Student-Centered classes (5.8x) occur for instructors who attended two topical PD events but were observed teaching a different topic. Models suggest that instructors with at least 24 h of PD are significantly more likely to teach a Student-Centered class than instructors with fewer hours. Our results highlight the effectiveness of disciplinespecific PD in impacting teaching practices, and the importance of attending more than one such PD event to aid transfer of learning.