Alberto Mendez

The Relationship Between Attendance in Student‐centred Physics Tutorials and Performance in University Examinations

The School of Physics at the University of Sydney has introduced voluntary workshop tutorials in large first‐year courses. The tutorials are based on informal cooperative groupings with structured worksheets and short hands‐on activities. In this study we explore the relationship between attendance at the workshop tutorials and student performance in examinations. We show that about 80% of the students attend more than two‐thirds of the voluntary tutorials. Discounting the students who attend very few tutorials, on average, examination marks improve significantly with increased tutorial attendance. In particular, on average, students with poor senior high school scores have significantly better examination marks if they work in the same group for eight or more tutorials than those who do not work in the same groups. There is evidence that the improvement in examination performance is more pronounced in qualitative concept questions, most dramatically again for students who did poorly in senior high school.

Orbital parameters, masses and distance to β Centauri determined with the Sydney University Stellar: Interferometer and high-resolution spectroscopy

The bright southern binary star β Centauri (HR 5267) has been observed with the Sydney University Stellar Interferometer (SUSI) and spectroscopically with the European Southern Observatory Coude Auxiliary Telescope and Swiss Euler telescope at La Silla. The interferometric observations have confirmed the binary nature of the primary component and have enabled the determination of the orbital parameters of the system. At the observing wavelength of 442 nm the two components of the primary system have a magnitude difference of 0.15 ± 0.02. The combination of interferometric and spectroscopic data gives the following results: orbital period 357.00 ± 0.07 d, semimajor axis 25.30 ± 0.19 mas, inclination 67. ◦ 4 ± 0. ◦ 3, eccentricity 0.821 ± 0.003, distance 102.3 ± 1.7 pc, primary and secondary masses M 1 = ( ◦ )( ◦ ) .

A new determination of the orbit and masses of the Be binary system δ Scorpii

The binary starδ Sco (HD143275) underwent remarkable brightening in the visible in 2000, and continues to be irregularly variable. The system was observed with the Sydney University Stellar Interferometer (SUSI) in 1999, 2000, 2001, 2006 and 2007. The 1999 observations were consistent with predictions based on the previously published orbital elements. The subsequent observations can only be explained by assuming that an optically bright emission region with an angular size of 2 ± 1 mas formed around the primary in 2000. By 2006/2007 the size of this region grew to an estimated 4m as. We have determined a consistent set of orbital elements by simultaneously fitting all the published interferometric and spectroscopic data as well as the SUSI data reported here. The resulting elements and the brightness ratio for the system measured prior to the outburst in 2000 have been used to estimate the masses of the components. We find MA = 15 ± 7M � and MB = 8.0 ± 3.6 M� . The dynamical parallax is estimated to be 7.03 ± 0.15 mas, which is in good agreement with the revised Hipparcos parallax.

Orbital elements, masses and distance of λ Scorpii A and B determined with the Sydney University Stellar Interferometer and high-resolution spectroscopy

The triple system HD 158926 (λ Sco) has been observed interferometrically with the Sydney University Stellar Interferometer, and the elements of the wide orbit have been determined. These are significantly more accurate than the previous elements found spectroscopically. The inclination of the wide orbit is consistent with the inclination previously found for the orbit of the close companion. The wide orbit also has low eccentricity, suggesting that the three stars were formed at the same time. The brightness ratio between the two B stars was also measured at λ= 442 and 700 nm. The brightness ratio and colour index are consistent with the previous classification of λ Sco A as B1.5 and λ Sco B as B2. Evolutionary models show that the two stars lie on the main sequence. Since they have the same age and luminosity class (IV), the mass–luminosity relation can be used to determine the mass ratio of the two stars: M_B/M_A= 0.76 ± 0.04. The spectroscopic data have been reanalyzed using the interferometric values for P, T, e and ω, leading to revised values for a_1 sin i and the mass function. The individual masses can be found from the mass ratio, the mass function, spectrum synthesis and the requirement that the age of both components must be the same: M_A= 10.4 ± 1.3 and M_B= 8.1 ± 1.0 M_⊙. The masses, angular semimajor axis and the period of the system can be used to determine the dynamical parallax. We find the distance to λ Sco to be 112 ± 5 pc, which is approximately a factor of 2 closer than the Hipparcos value of 216 ± 42 pc.

What does a physics undergraduate education give you? A perspective from Australian physics

In a study to assess how effectively undergraduate physics studies have prepared students for the workplace, we attempted to locate and interview traditional 3-year or 4-year physics students who had graduated in the past five years (2000 to 2004), and the employers of these graduates. The study was limited to recent graduates who have majored in physics and not obtained further or concurrent degrees. Overseas studies of the destinations of physics graduates referred to in this paper have not isolated the group we interviewed as a distinct group. A major finding was that the number of these graduates was unexpectedly low. Indeed, most physics graduates have two degrees. Interviews with graduates and employers suggest that physics graduates have particular strengths in problem solving and are good at applying their skills at the workplace.

Educational analysis of a first year engineering physics experiment on standing waves: based on the ACELL approach

This paper describes an educational analysis of a first year physics experiment on standing waves for engineering students. The educational analysis is based on the ACELL (Advancing Chemistry by Enhancing Learning in the Laboratory) approach which includes a statement of educational objectives and an analysis of student learning experiences. The experiment is likely to be found in many physics departments, hence is appropriate to illustrate the ACELL approach in physics. The concepts associated with standing waves are difficult; however, they are underpinned by mathematical formulation which lend themselves to be visualized in experiments. The challenge is to strike a balance between these two for the particular student cohort. In this study, this balance is achieved by using simple equipment and providing appropriate scaffolds for students to associate abstract concepts with concrete visuals. In essence the experiment is designed to adequately manage cognitive resources. Students work in pairs and are questioned and assisted by demonstrators and academic staff during a 2 h practical class. Students were surveyed using the ACELL instrument. Analysis of the data showed that by completing the practical students felt that their understanding of physics had increased. Furthermore, students could see the relevance of this experiment to their engineering studies and that it provided them with an opportunity to take responsibility for their own learning. Overall they had a positive learning experience. In short there is a lot of dividend from a small outlay of resources.

Student evaluation of research projects in a first-year physics laboratory

We describe the evaluation by students of a scheme of open-ended, research-based group project work which has become a standard component of first-year physics courses at the University of Sydney and is now in its 19th year of operation. Data were gathered from two sources: direct observations of the classes and a written survey. A summary of the classroom observations and the results from a detailed analysis of the survey responses are presented. The feedback from the cohort of approximately 800 students is largely positive but we identify a few discrepancies between stated course goals and the results from the survey.

Sydney University Stellar Interferometer Program

The Sydney University Stellar Interferometer (SUSI) is a long baseline optical interferometer located at the Paul Wild Observatory in northern New South Wales, some 400 km NNW of Sydney. An extensive observational and development program is in progress. The status of the observational program, data reduction techniques, and recent results are reported. Instrumental developments including the development and installation of new tip-tilt mirrors and the design and implementation of a red beam-combination system that includes a group-delay tracker will be described. Auxiliary instrumentation to provide complementary data for the interpretation of SUSI observations has been installed alongside SUSI and this will be outlined briefly.