Physics

The distribution of string tension on the contact line between an ideal string and a massive pulley is a frequently-discussed but incompletely-posed problem that confronts students in introductory mechanics. We highlight ambiguities in the usual presentation of this problem by the massive Atwood's machine and discuss two compact resolutions that treat situations where the pulley or the string elastically deform. We propose experiments that can be developed in an intermediate laboratory to determine the tension profile.

Students with disabilities are enrolling in postsecondary education in increasing numbers and in science, technology, engineering, and mathematics (STEM) at steady rates since the early 1990s. Specifically, in 2014, the National Center on Science and Engineering Statistics (NCSES) found that 10.5% of students enrolled in science and engineering degree programs identified with a disability. However, postsecondary faculty have been shown to be unprepared to support students with disabilities in their classes and popular, research-based introductory physics curricula do not adequately plan for variations in learners' needs, abilities, and interests. The purpose of this paper is to provide resources that instructors can use in their classes to promote accessibility and support all learners. In this paper we: 1) provide a brief review of the literature related to supporting students with disabilities in the context of physics; 2) describe a design framework intended to encourage development of curricula that support all learners; and 3) provide a list of resources that physics instructors can use to increase support for students with disabilities.

Teamwork assessments often result in a single final product, for which all team members receive a single mark regardless of their contribution to the team project. In order to respond to feedback from students in terms of fair marking of the teamwork assessment, we implemented peer assessment as a recommended pedagogical intervention to individualise team marks and prevent team members from taking advantage of free riding. Team marks were individualised proportional to the average peer assessment mark each student received from their peers in the team. We analysed course evaluation data before and after the implementation of the peer assessment process from students participating in Engineering Design courses. Analysing data in light of Social Interdependence Theory showed that the peer assessment process improved the cooperation of the team members which enhanced the students teamwork experience and their engagement with the course.

The aim of this paper is to present the impact achieved by Frascati Scienza Association on society and research through the European Researchers' Night project funded by the European Commission within the years 2006-2015. The project has been devoted to raise awareness of researchers' work, encourage the dialogue between researchers and citizens and the choice of young people to pursue a career in science. The first scientific activities and cultural events took shape in 2006, under the coordination of the National Institute for Nuclear Physics (INFN), through the European Researchers' Night project, the most important and significant event to promote the role of the researcher and bring people of all ages closer to the scientific world. The positive and successful experience of the first two events, pushed the researchers and citizens of Frascati, where most of Italian research centers and infrastructures are located, to formally associate in the Frascati Scienza in 2008, who started to coordinate the event from 2008. Frascati Scienza was driven by the need to promote educational activities to citizens, young people and schools, in order to involve the general public in science and to bring researchers closer to society.

The cyclic format of the undergraduate physics curriculum depends on students' ability to recall and utilize material covered in prior courses in order to reliably build on that knowledge in later courses. However, there is evidence to suggest that people often do not retain all, or even most, of what they learned previously. How much information is retained appears to be dependent both on the individuals' approach to learning as well as the style of instruction. In particular, there is evidence to suggest that active engagement techniques in the classroom can improve students' retention of the material over time. Here, we report the findings of a longitudinal investigation of students' retention of conceptual understanding as measured by the Force and Motion Conceptual Evaluation (FMCE) following a first-semester, calculus-based introductory physics course, which features significant active engagement in both lecture and recitation. By administering the FMCE at the end of a first-semester physics course and again at the beginning of the subsequent second-semester physics course, we examine students' knowledge retention over time periods ranging from 1-15 months. We find that the shift in students' FMCE scores between these two courses is positive but corresponds to a small effect size, indicating that students retained effectively all of their conceptual learning (as measured by the FMCE). This finding largely persists even as the length of the gap between the two courses increases. We also find that, when breaking out students' performance on individual questions, the majority of students maintain their score on individual questions. Averaged over all questions, roughly a fifth of the students switched their answers from right to wrong or wrong to right on any given item.

Electrification by rubbing different materials is a well known phenomenon with a history that begun more than five centuries BC. However, simple experiments can lead to contradictory or inconsistent results and the history of this phenomena is plagued with non-intuitive results. For example, triboelectric charging by rubbing identical materials is possible. In this work we want to highlight some historical aspects of triboelectricity that could enrich the discussion of electrostatics in an undergraduate physics course. We will focus on the effect of strain on the triboelectric properties of a sample, which we think is not well known to physics teachers. We will show that it is possible to obtain robust polarities by rubbing identical rubber balloons of different radii and we will also show that this charging method can be very useful in introductory physics courses.

In the spring of 2018 the Northern California/Nevada section of the American Association of Physics Teachers was alerted to a local high school's plans to eliminate physics for the following school year. As part of the campaign to support the school's efforts to sustain physics in the following year, the physics offerings from the surrounding schools in that district were compiled. It appeared that the demographics of the student population in the district played a role in the number of different physics courses offered within that district, particularly the percentage of Hispanic students (%Hispanic) and percentage of socioeconomically disadvantaged (%SED) students at each school. Concerned that this trend was more widespread, physics course offerings were reviewed for Northern California public high schools to determine if there were correlations between the amount of different physics class offerings and these populations. It was found that %Hispanic and %SED are strongly correlated in California public schools, and along with number of students, could be used as statistically significant predictors of a school's physics offerings.

Many optical microscopy techniques rely on structured illumination by way of a projected image (eg. structured illumination microscopy) or a tailored angular distribution of light (eg. ptychography). Electro-optical equipment such as spatial light modulators and light emitting diode (LED) arrays are commonly used to sculpt light for these imaging schemes. However, these high-tech devices are not a requirement for light crafting. Patterned diffusely reflecting surfaces also imprint a spatio-angular structure onto reflected light. We demonstrate that paper patterned with a standard commercial printer can serve to structure the illumination light field for refocusing and stereo microscopy on a mobile phone microscope. Our results illustrate the utility of paper as a light sculpting element for low-tech computational imaging.

In its most general form, a `secret objective' is any inconsistency between the experimental reality and the information provided to students prior to starting work on an experiment. Students are challenged to identify the secret objectives and then given freedom to explore and understand the experiment, thus encouraging and facilitating genuine inquiry elements in introductory laboratory courses. Damping of a simple pendulum is used as a concrete example to demonstrate how secret objectives can be included. We also discuss the implications of the secret objectives method and how this can provide a link between the concepts of problem based learning and inquiry style labs.

In this activity, students will make a working model of an atomic force microscope (AFM). A permanent magnet attached to a compact disc (CD) strip acts as the sensor. The sensor is attached to a base made from Legos. Laser light is reflected from the CD sensor and onto a sheet of photosensitive paper. An array of permanent magnets attached to cardboard acts as the atoms on a surface. When the sensor is brought near this atomic surface the magnets will deflect the sensor, which in turn deflects the reflected laser. This deflection is recorded on the photosensitive paper, which students can take home with them.