No Arabic abstract
The detection and study of extrasolar planets is an exciting and thriving field in modern astrophysics, and an increasingly popular topic in introductory astronomy courses. One detection method relies on searching for stars whose light has been gravitationally microlensed by an extrasolar planet. In order to facilitate instructors abilities to bring this interesting mix of general relativity and extrasolar planet detection into the introductory astronomy classroom, we have developed a new Lecture-Tutorial, Detecting Exoplanets with Gravitational Microlensing. In this paper, we describe how this new Lecture-Tutorials representations of astrophysical phenomena, which we selected and created based on theoretically motivated considerations of their pedagogical affordances, are used to help introductory astronomy students develop more expert-like reasoning abilities.
Science students must deal with the errors inherent to all physical measurements and be conscious of the need to expressvthem as a best estimate and a range of uncertainty. Errors are routinely classified as statistical or systematic. Although statistical errors are usually dealt with in the first years of science studies, the typical approaches are based on manually performing repetitive observations. Our work proposes a set of laboratory experiments to teach error and uncertainties based on data recorded with the sensors available in many mobile devices. The main aspects addressed are the physical meaning of the mean value and standard deviation, and the interpretation of histograms and distributions. The normality of the fluctuations is analyzed qualitatively comparing histograms with normal curves and quantitatively comparing the number of observations in intervals to the number expected according to a normal distribution and also performing a Chi-squared test. We show that the distribution usually follows a normal distribution, however, when the sensor is placed on top of a loudspeaker playing a pure tone significant differences with a normal distribution are observed. As applications to every day situations we discuss the intensity of the fluctuations in different situations, such as placing the device on a table or holding it with the hands in different ways. Other activities are focused on the smoothness of a road quantified in terms of the fluctuations registered by the accelerometer. The present proposal contributes to gaining a deep insight into modern technologies and statistical errors and, finally, motivating and encouraging engineering and science students.
The Lecture-Tutorials for Introductory Astronomy have been designed to help introductory astronomy instructors actively engage their students in developing their conceptual understandings and reasoning abilities across a wide range of astrophysical topics. The development of the Lecture-Tutorials has been informed by nearly two-decades of research into common learning difficulties students experience when studying astronomy. The results from multiple studies provide evidence that Lecture-Tutorials can help students achieve learning gains well beyond what is typically achieved by lecture alone. Achieving such learning gains requires that an instructor understand how to effectively incorporate the Lecture-Tutorials into his or her course. This chapter provides details into the best practices for the effective integration and implementation of the Lecture-Tutorials - practices that we have developed through years of reflective practice from working with thousands of Astro 101 students and instructors. We also present a case study of how Lecture-Tutorials were used to promote the active engagement of learners in an Astro 101 mega-course enrolling over 700 students. This case study illustrates how the thoughtful implementation of Lecture-Tutorials can result in dramatic learning gains, even in the most daunting instructional environments.
As part of a larger research project into massively open online courses (MOOCs), we have investigated student background, as well as student participation in a physics MOOC with a laboratory component. Students completed a demographic survey and the Force and Motion Conceptual Evaluation at the beginning of the course. While the course is still actively running, we have tracked student participation over the first five weeks of the eleven-week course.
The Physics Inventory of Quantitative Literacy (PIQL), a reasoning inventory under development, aims to assess students physics quantitative literacy at the introductory level. The PIQLs design presents the challenge of isolating types of mathematical reasoning that are independent of each other in physics questions. In its current form, the PIQL spans three principle reasoning subdomains previously identified in mathematics and physics education research: ratios and proportions, covariation, and signed (negative) quantities. An important psychometric objective is to test the orthogonality of these three reasoning subdomains. We present results from exploratory factor analysis, confirmatory factor analysis, and module analysis that inform interpretations of the underlying structure of the PIQL from a student viewpoint, emphasizing ways in which these results agree and disagree with expert categorization. In addition to informing the development of existing and new PIQL assessment items, these results are also providing exciting insights into students quantitative reasoning at the introductory level.
The nascent field of gravitational-wave astronomy offers many opportunities for effective and inspirational astronomy outreach. Gravitational waves, the ripples in space-time predicted by Einsteins theory of General Relativity, are produced by some of the most energetic and dramatic phenomena in the cosmos, including black holes, neutron stars and supernovae. The detection of gravitational waves will help to address a number of fundamental questions in physics, from the evolution of stars and galaxies to the origin of dark energy and the nature of space-time itself. Moreover, the cutting-edge technology developed to search for gravitational waves is pushing back the frontiers of many fields, from lasers and materials science to high performance computing, and thus provides a powerful showcase for the attractions and challenges of a career in science and engineering. For several years a worldwide network of ground-based laser interferometric gravitational-wave detectors has been fully operational, including the two LIGO detectors in the United States. These detectors are already among the most sensitive scientific instruments on the planet and in the next few years their sensitivity will achieve further significant improvement. Those developments promise to open an exciting new window on the Universe, heralding the arrival of gravitational-wave astronomy as a revolutionary, new observational field. In this paper we describe the extensive program of public outreach activities already undertaken by the LIGO Scientific Collaboration, and a number of special events which we are planning for IYA2009.