We present ground-based optical observations of the September 2009 and January 2010 transits of HD 80606b. Based on 3 partial light curves of the September 2009 event, we derive a midtransit time of T c [HJD] = 2455099.196 ± 0.026, which is about 1σ away from the previously predicted time. We observed the January 2010 event from 9 different locations, with most phases of the transit being observed by at least 3 different teams. We determine a midtransit time of T c [HJD] = 2455210.6502 ± 0.0064, which is within 1.3σ of the time derived from a Spitzer observation of the same event.

Over the course of instruction, not only does most introductory physics students' content knowledge evolve but their attitudes and approaches to problem solving are also likely to evolve. This change may depend on many factors including the curricula and pedagogies used, the degree to which instruction actively engages students in the learning process, as well as the gender of the students. While changes in epistemology and beliefs about physics have been examined in the literature, how students' attitudes and approaches to problem solving change from the beginning to the end of instruction in introductory physics and how method of instruction or gender of the student impact them remain largely unexplored. To examine the potential changes in attitudes and approaches to problem solving over a semester, we administered a previously validated attitudes and approaches to problem solving (AAPS) survey both at the beginning (pre) and at the end of instruction (post) in eight large enrollment calculus-based introductory physics classes at a large research university in the United States. At both points in time (beginning and end of a semester of instruction), each class was also given surveys measuring students' conceptual understanding: the Force Concept Inventory (FCI) or the Conceptual Survey of Electricity and Magnetism (CSEM), depending upon whether it was the first or second semester course. In addition, final exam scores, gender of students, and descriptions of the instructional methods used for each class were collected. The AAPS survey was used to measure students' attitudes and approaches to problem solving, and the conceptual surveys and exam scores were used to measure the degree to which each course helped students learn physics concepts. We examined students' performance on the AAPS survey, FCI or CSEM, and final exams, and compared the results for different instructional methods, and gender of students. Moreover, we examined whether or not there were correlations between the expertlike response on the AAPS survey and the performance on FCI or CSEM or final exams. We found that all classes exhibited a decline in score on the AAPS survey suggesting worse attitudes related to problem solving after instruction. Furthermore, controlling for the initial scores, classes which involved significant use of evidence-based active engagement methods exhibited statistically significantly better scores on the AAPS survey at the end of the course compared to classes which were taught primarily using a traditional lecture-based approach. Equally importantly, unlike broader epistemological surveys, female students were found to exhibit less of a decline in AAPS scores than did their male counterparts in all classes and the AAPS scores were always higher for female students at the end of the course. Future research should contemplate how this novel finding may be effectively exploited to develop and implement curricula and pedagogies to reduce the gender gap in performance often observed in introductory physics.

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Physics problems can be posed in different ways. Given a physics scenario, different problem types presenting that scenario in various ways can emphasize different instructional goals. In this investigation, we examined the views of physics graduate teaching assistants (TAs) enrolled in a semester-long TA professional development course about the instructional benefits of different types of introductory problems based upon the same problem scenario to generate discussion and reflection on their use in different instructional situations. The TAs were asked to list the pros and cons of the problem types, rank them in terms of their instructional benefit and the level of challenge they might produce for their students, and describe when and how often they would use different types of problems in their own classes if they had complete control of teaching the class. Here we report on TAs' views about two of these problem types that were regarded by TAs as the least instructionally beneficial of all problem types-the context rich and multiple-choice formats. Many TAs listed no pros at all for these problem types, despite being explicitly asked for at least one pro. They viewed multiple-choice questions nearly exclusively as tools for high-stakes summative assessment rather than their possible use as formative assessment tools, e.g., as clicker questions even in large classes. Similarly, TAs viewed context-rich problems as overly challenging, unnecessarily wordy, and too time-consuming to be instructionally beneficial to their students. It is possible that in the written responses, TAs could have focused on the example problems provided to illustrate each problem type. Therefore, discussion in the TA professional development class and in the follow-up interviews explicitly included a focus on the general instructional benefits of well-designed multiple-choice and context-rich problems in different instructional contexts based upon the goals. It appears that TAs' sentiments were general views about these types of problems, and not just their views about the specific examples that the TAs were given in order to illustrate a problem type. While TAs' concerns have obvious validity and value, the benefits of well-designed multiple-choice questions as a formative assessment tool was not readily identified by them, nor did the TAs recognize the learning benefits associated with solving context-rich problems. Given the powerful ways multiple-choice and context-rich problems can be used for active engagement and formative assessment in different instructional contexts to meet diverse instructional goals, the lack of enthusiasm for these types of problems has implications for future TA professional development programs. arXiv:1907.00521v1 [physics.ed-ph] 1 Jul 2019

Students taking introductory physics and introductory astronomy classes, which are both gateways to a physics or physics and astronomy major, may have different attitudes and approaches to problem solving. We examined how introductory physics students' attitudes and approaches to problem solving compare to those of introductory astronomy students, using a previously validated survey, the Attitudes and Approaches to Problem Solving (AAPS) survey. In addition, we compared the performance of the introductory physics and astronomy students on the factors which were identified in a factor analysis in the original validation study. We found that introductory astronomy students' overall average AAPS score was significantly more favorable than that of introductory physics students (p < 0.01), and the effect size was large (Cohen's d = 0.81). We also found that introductory astronomy students' scores were more favorable in all clusters of questions except for one factor involving drawing diagrams and writing scratchwork while solving problems. Follow-up interviews suggest that one possible explanation for less favorable scores in this factor is the context of astronomy problems, e.g., the difficulty and usefulness of drawing electromagnetic radiation. Moreover, introductory astonomy students who were interviewed indicated that they would likely draw diagrams for problems that lend themselves well to sketching, such as problems involving celestial mechanics. We also found that introductory physics and astronomy students were equally capable of solving two isomorphic problems posed to them, and that the majority of introductory physics and introductory astronomy students reported that the problem posed in the astronomy context was more interesting to them. Interviews suggest that the context of astronomy in problem solving may be more interesting for students and could be one possible explanation for the more favorable AAPS scores amongst introductory astronomy students compared to introductory physics students. Instructors of introductory physics courses should heed these findings which indicate that it may be beneficial for instructors of introductory physics courses to incorporate problems into their instruction which contain real-world contexts, which may serve to increase student interest-level, and which could help create more favorable attitudes and approaches towards problem solving.