Table of contents

The physics of a hula hoop is determined primarily by the effect of the centripetal force acting on the hoop. However, the friction force on the hoop also plays a role. A simple experiment is described showing how an increase in the friction coefficient can help to prevent the hoop falling.

Measuring time of motion using photogates is a good solution when the moving object has plane surfaces or when you can put upon it a plane surface object, which acts as a beam stopper. There are however situations where other devices, and in particular micro-switches, although they are much cheaper than photogates, perform at least as well as photogates. In this frontline, I describe how we can construct an inclined plane equipped with micro-switches and how we can use it in experiments involving rolling cylinders.

This study aims to determine the angular velocity of a simple propeller with a smartphone proximity sensor. The results show that the smartphone proximity sensor can be a useful tool to determine angular velocity in uniform circular motion. Teachers and students are advised to perform the funny and easy physics experiment described in this study.

In this work we present a water-driven clock (clepsydra) that uses the water that flows from a Mariotte flask to work. By designing and building all the elements properly, we get the seconds hand to make a full turn (1 min) at the right pace.

The aim of this study is to draw attention to the language-based misconceptions and confusions about the term binding energy and to make suggestions to educators on this issue.

Integrals of functions of the form $f\,(x) = x^{n}{\textrm{e}}^{-ax}$ over the domain $(0,\infty)$ occur in various areas of physics. This paper shows how students can evaluate such integrals to surprisingly good accuracy using only basic calculus.

The quantum eraser is a variation of the celebrated Young's interference experiment that can be used to demonstrate the elusive complementarity principle in quantum physics. Here we show the construction of its classical analogue for deployment in classrooms in a simple, cost-effective yet robust manner by employing a laser pointer, double-slits, and polarizers.

A movie of the moving temperature pointer of a dial-type thermometer was analysed in Tracker, a machine vision application, revealing a satisfactory match between the theory and the experimental data. Also presented is an empirical model for the time-dependent angular positions of the pointer.

The two main expressions for power dissipation P in Ohmic conductors, namely $P\propto V^{\,2}$ and $P\propto I^{\,2}$, typically confuse students about why high voltage V should be preferred to high current I when transmitting electrical power through the National Grid. Here we suggest that such misconceptions can be avoided if students are encouraged to focus on the delivery of useful power (transmission efficiency), rather than energy losses.

Induced seismicity has received a lot of attention in recent years. This new natural phenomenon appeared as a result of active human influence on nature. The phenomenon has been detected in places of natural gas and oil recovery, and geological storage of CO₂. One of the main reasons for the observed seismic activity is associated with the adsorption-induced deformation of rocks. We present experimental data and a simple model describing adsorption-induced deformation using the example of the Berea sandstone. We suggest a simplified experiment for the undergraduate university laboratory.

We present our outreach program, the Thailand–UK Python+Astronomy Summer School (ThaiPASS), a collaborative project comprising UK and Thai institutions and assess its impact and possible application to schools in the United Kingdom. Since its inception in 2018, the annual ThaiPASS has trained around 60 Thai high-school students in basic data handling skills using Python in the context of various astronomy topics, using current research from the teaching team. Our impact assessment of the 5 day summer schools shows an overwhelmingly positive response from students in both years, with over 80% of students scoring the activities above average in all activities but one. We use this data to suggest possible future improvements. We also discuss how ThaiPASS may inspire further outreach and engagement activities within the UK and beyond.

The aim of this study is to design an argumentation-based educational digital game to teach the subject of force. Through a design-based research method, each game section includes the argumentation questions that foster students to think about the 'force' subject. We pilot studied the game with 12 grade 4 students in a state primary school. After successive three pilot studies, we revised and fixed technical and pedagogical problems. We believe that the argumentation-based digital game has the potential to improve grade 4 students' argumentation qualities and stimulate their learning interest/motivations.

This paper shows how two distinct but related models can be used to bring out the essential physics of heat flow in one dimension. The first is a simple step-wise procedure using SMath Studio, while the second is an electric analogue using a basic RC ladder connected to an Arduino microcontroller. Both models can be demonstrated in real time within a lecture or teaching-laboratory environment. Differences and similarities of the two approaches are discussed.

A concept for undergraduate mechanics courses at universities is introduced where traditional pencil-paper based exercises are partially replaced by experimental exercises, in which smartphones are used as measurement devices. A detailed guidance for practical realization and implementation of these tasks formats into the course is presented. Three smartphone-based experimental exercises 'The tilting smartphone', 'The oscillation balance' and 'Using the Smartphone in a Torsion Pendulum' are presented. First empirical results with respect to the learning achievement indicate a mid size effect on the understanding of the physical concepts. Compared to the traditional pencil-paper based exercises, the students performance in the experimental exercises is slightly lower, although the motivation to solve these tasks is higher.

Huygens' principle in which every point on a propagating wave acts like a point source of radiation is a foundation principle of physics. Normally, Huygens' principle is demonstrated by passing a wave, for example a water or light wave through an aperture comparable in size to the wavelength. In this paper, an experiment is described in which a 0.1 mm diameter copper wire is placed in front of a laser pointer to demonstrate Huygens' principle in empty space. The diffraction pattern was photographed using a phone camera, and the bandwidth measured using a free image analysis program, ImageJ. The diffraction diameter of the wire was $0.095\,\; \pm \;0.005\;{\text{mm}}.$ The experiment can easily be performed in a classroom.

We developed new teaching materials, electrical resistors and capacitors, using carbon nanotube (CNT) paper and carbon fibre (CF) paper to foster students' creative thinking, thereby deepening and extending learning. Using a CNT-paper electrical resistor, it is possible to elucidate the dependence of the resistance value on the length and width. The resistance value is proportional to the length and inversely proportional to the width of the paper. In the case of the CF-paper capacitor, it is also possible to clarify the dependence of the capacitance value on the area and the distance between papers. The capacitance value is proportional to the areas of the papers and inversely proportional to the distance between them. Based on the results of our experiments using the new teaching materials, we confirmed that the measured values were in good agreement with the values predicted by theoretical calculations. Using these materials, it becomes possible for students to visually and actively learn about electrical resistance and capacitance through experiments by themselves and in discussion with other students, in contrast to the traditional teaching methods practiced in many schools worldwide. We found that teaching methods using these materials are a useful and easy way to teach the basic concepts of resistance and capacitance with geometric factors in classrooms.

In the epidemic period, online teaching has become the most important teaching form. On the basis of questions-centred massive open online courses (MOOCs) teaching, the online teaching mode of college physics was studied and discussed using the Tencent classroom, WeChat/QQ and Wisdom Tree Platform. MOOCs before class, Tencent classroom during class, WeChat/QQ in the whole process including solving problems after class, and Wisdom Tree Platform for quality inspection of online teaching were practiced in the teaching of each chapter including mass point kinematics. Due to the problem-oriented implementation of the three stages, the results of the online mock test were better than expected. In other words, the online teaching supported by various online tools could effectively guarantee the quality of teaching.

The role of peer and teacher mediation in discussions about two original scientific texts in the final year of high school in Brazil is explored in this study. A text by James C Maxwell, deals with the characterisation of light as an electromagnetic phenomenon, and refers to the continuous manner of the distribution of energy by radiation in space. The other, by Ludwig Boltzmann, is about thermodynamics in its probabilistic conception and some of its consequences for the comprehension of the nature of heat. We analyse some of the students' interpretations using a version of discourse analysis, developed in Brazil following the French tradition of Michel Pêcheux. We highlight interactions that contribute to the reading of the texts and the mediations of both the teacher and peers that promote the establishment of relevant meanings about physics concepts. The appropriation of their statements about the content is observed in this communicative approach. We contribute to the investigation of physics teaching using strategies informed by a humane scientific and cultural educational perspective in high schools.

In this study, it is aimed to calibrate an LDR-Lux meter with a calibration setup which includes a light bulb whose brightness can be changed by using a dimmer circuit, a data acquisition card, a smartphone and a lux meter application. In order to make the measurements more accurate and to prevent errors in the measurements, a smartphone and a laptop were connected to each other via internet browser and the data obtained with physical phone experiments was displayed on the computer screen instantly. In the experimental setup, the brightness of the light was changed with the dimmer circuit and height adjustment. The data were obtained as a result of 32 experiments for different illumination values. As a result of this study, it is seen that the calibrated experimental setup works with high accuracy. With this experimental setup, it is thought that students can also easily test the inverse square law of light. The main factors that make this experimental setup effective are that, unlike other studies in the literature, a professional lux meter is not used and the cost of the developed LDR-Lux meter is very low.

We describe an educational activity that can be done by using smartphones to collect data in physics experiments aimed to measure the oscillating period of a spring-mass system and the elastic constant of the helicoidal spring by the dynamic method. Results for the oscillating period and for the elastic constant of the spring agree very well with measurements obtained by different methods. We also discuss the error analysis that can be done in an introductory physics laboratory at undergraduate level.

Dark matter is one of the most intriguing scientific mysteries of our time and offers exciting instructional opportunities for physics education in high schools. The topic is likely to engage and motivate students in the classroom and allows addressing open questions of the Standard Model of particle physics. Although the empirical evidence of dark matter links nicely to many standard topics of physics curricula, teachers may find it challenging to introduce the topic in their classrooms. In this article, we present a fun new approach to teach about dark matter using jelly lenses as an instructional analogy of gravitational lenses. We provide a brief overview of the history of dark matter to contextualise our presentation and discuss the instructional potential as well as limitations of the jelly lens analogy.

We present a simple activity based on the liquid-drop model which allows secondary school students to explore the uses of mathematical models and gain an intuitive understanding of the concept of binding energy, and in particular the significance of positive binding energy. Using spreadsheets provided as supplementary material, students can perform simple manipulations on the different coefficients of the model to understand the role of each of its five terms. Students can use the spreadsheets to determine model parameters by optimising the agreement with real atomic mass data. This activity can be used as the starting point of a discussion about theoretical models, their validation when it comes to describing experimental data and their predictive power towards unexplored regimes.

In science learning, the experiment is an essential activity to facilitate students to discover and develop knowledge as well as to enhance scientific process skills and self-confidence. This study aims to create a simple experimental apparatus related to the principle of fluid continuity that can be made and conducted by the teacher and student as a learning media. Basic tools were used to assemble this homemade experiment and a free video analysis software, Tracker, was used to determine and analyse the fluid velocity. The experimental results showed that the fluid flows faster in the small hose than the larger one, which is in line with the fluid continuity principle. Nevertheless, there is a slightly different volumetric water flux (Q) in both hoses.

In this study, we develop a capacitive rotating angle sensing system using a hand-made 1 kHz oscillator, field-effect transistor (FET) amplifier, and tester through a physics experiment conducted in Ryukoku University. Physics majors of the university can study the fundamentals of electronics through this system because it uses electronic elements, such as transistors and FETs. We fabricated the circuit of a rotation angle sensor system using a fan-type and coaxial variable capacitor. The capacitance of the variable capacitors varied linearly with the rotation angle. Owing to the CR high-pass filter, constructed by capacitors and a 100 kΩ resistor, the output voltage of the system was linear with capacitors and the rotation angle. Not only can this system be used to teach university-level physics, but its applications could extend to various industries.

In Brazil, environmental topics in teacher education programmes have largely been addressed and explored by the field of research in Environmental Education and subsidized by legislative and normative instruments. Nevertheless, the difficulties in articulating environmental topics within some areas of knowledge compromise their integration in certain subject-specific courses, as is the case for initial physics teacher education courses. In this light, this article seeks to identify the main challenges and motivations to incorporating environmental topics in physics teacher education courses, with the aim of identifying strategies that may contribute to overcoming these difficulties. Interviews were carried out with 15 physics teacher education courses coordinators at state-funded higher education institutions in the state of São Paulo, Brazil. Drawing upon Content Analysis procedures, analysis was conducted on the interview transcripts as well as pedagogical plan courses. The main findings highlight that the presence of environmental topics in these programmes reflects legislative and normative requirements. In addition, other factors motivated the inclusion of environmental topics in these courses, thus indicating recognition of its importance to initial physics teacher education. This study also shows that the small number of university lecturers and professors involved in environmental education working within these programmes is the main challenge to including environmental topics in initial physics teacher education curriculum.

The target of this study is to determine the minimum angle of deviation of a prism which is one of the optical experiments. Thus, the aim is to state the refractive index of a prism. In this context, the Tracker program, which might also be utilized in terms of distance education purposes, was preferred. The videos of the experiments were recorded with the help of a smartphone. The study showed that the refractive indexes of the prisms which were made of glass and acrylic with different apex angles could be determined with a high level of accuracy as a result of the analysis of videos which were recorded with two different methods. It is believed that the study provides insights for both the conduction of laboratory courses via distance education and for performing experiments for students who do not have access to proper laboratory equipment.

A standard problem for physics students is to calculate or measure the acceleration of an object down an inclined plane. Additional information can be obtained by measuring the angular acceleration as well as the linear acceleration. An experiment is described where a billiard ball was filmed as it rolled down an inclined plane at different inclination angles. The transition from rolling without slipping to rolling with slipping was identified, and the relevant friction coefficients were measured independently from the linear and angular accelerations.

Since the viscous behaviour of liquids is evident in many everyday situations, it is plausible to assume that students have (pre-)conceptions about the physics behind these phenomena. As yet, no reliable studies exist on this topic. Therefore, the present study aims to address this research gap by exploring secondary school students' conceptions about the viscous behaviour of liquids. For this purpose, we conducted structured interviews with 12 ninth grade students, in which the students were asked to describe and explain various viscosity phenomena of everyday life, presented to them as video clips. Our analysis of the interviews revealed that many of the students have the conception that density is associated with viscous behaviour. In addition, some students explain viscous behaviour with reference to the ingredients of a liquid or by its stickiness or compression. Further, both macroscopic- and sub-microscopic-level explanations for the viscous behaviour of liquids emerged in the interviews.

This paper starts with an introduction to the concept of momentum current. It is followed by a discussion of its strength and density with the aid of several analogies made between momentum current and electric current. Based on the novel concepts of thermal charge and its quantity (entropy), the analogies are extended to entropy current. The broadened analogies cover the driving force and resistance of each current, the effects that the strength or density of each current has on their conductors, and the relationships between the above three currents and energy current, etc, which involve practical problems such as industrial safety, human thermal sensation, process control parameters as well as energy carriers and energy transport.

The Covid-19 pandemic has forced educational institutions to adjust their learning process to distance education or online learning. This paper explains how to teach optics during the Covid-19 pandemic by implementing project-based learning that can be supervised online. Students are instructed to design, characterize, and optimize droplet lenses to produce the highest possible lens resolving power by using the USAF-1951 test chart. To do project-based learning correctly, students must understand various optics concepts, such as the principle behind light propagation (Fermat's principle), determining focal lengths, compound lenses, lens aberrations, and lens resolving power. This paper also describes how to optimize droplet lenses to produce high resolving power with easy to handle and inexpensive materials.

This paper aims to introduce the initiative Escola Sirius para Professores do Ensino Médio (ESPEM, Sirius School for High School Teachers) hosted by the Centro Nacional de Pesquisa em Energia e Materiais (CNPEM, Brazilian Center for Research in Energy and Materials) and supported by the Sociedade Brasileira de Física (SBF, Brazilian Physical Society). The program covers the principles and applications of synchrotron radiation with expositive lectures, discussions, and visits to the CNPEM facilities. By using semi structured interviews, a remote focal group and surveys to find out the impact of ESPEM, we observed that the teachers shared their experience and disseminate the acquired knowledge with their peers and students.

When the thermal expansion of water is discussed in school or university lessons, functional relationships are often inferred without considering measurement uncertainties. Moreover, in some learning materials, the goal of experimentation and the experimental setup do not match. This creates the wrong picture of scientific practice. In this article we compare five experimental setups with different complexity to investigate the relationship between heat and volume change of water. We take different goals of experimentation into account, as well as measurement uncertainties. We compare the different experimental setups, show advantages and limitations, and give advises for their implementation in the classroom. By doing so, we demonstrate that thermal expansion can be very well adopted for applying scientific practice in school. It is shown that the more complex the experimental setup, the more precise the quantitative significance of the functional relationship.

Renewable energy is a trending topic due to its importance in today's society especially because of global warming. Because of its importance, this topic should be discussed at schools in an inclusive education environment. Experimental work is a very good activity to provide students effective conceptual discussions, but it is necessary to improve the teaching–learning process for an inclusive education paradigm. In this paper we propose a low-cost experimental activity using Arduino that allows regular students and blind students to explore together and understand features and properties about solar energy and a photovoltaic panel, such as how the electric power generated by the photocell depends on the angle of incidence of solar light and the load resistance of the circuit.

Single slit diffraction is part of many high-school physics curricula throughout the world. In this study, we aimed to investigate whether high-school physics teachers from Bosnia and Herzegovina, Serbia and North Macedonia are adequately prepared to discuss with their students about various aspects of the single slit diffraction pattern, particularly about vertical length of diffraction fringes. To that end we conducted a written survey which included 57 high-school physics teachers. Besides asking teachers about students' difficulties in learning about single slit diffraction, we also asked them to specify their own difficulties with this topic and required them to solve a conceptual task. Almost every second teacher believed that vertical length of diffraction fringes can be increased by changing shape or width of the slit and only 1 out of 57 teachers managed to correctly answer why diffraction fringes become shorter when we move away from the central maximum. We concluded that physics teacher education programmes should be changed to develop understanding of both, horizontal and vertical aspects of the diffraction pattern. To that end it is useful to provide learning opportunities which encourage combining ray and wave model of light.

Problems involving rotating systems analysed from an inertial frame, without invoking fictitious forces, is something that freshman students find difficult to understand in an introductory mechanics course. In this article we try to see what could be the factors that lead to this difficulty and propose a set of arguments that could be used to resolve the confusion. We take a specific example of a bead sliding without friction on a rotating rod to address the issues involved. After solving the problem in the inertial reference frame by integrating the equations of motion expressed in the plane polar coordinate system, we carry out a consistency check on how the radial motion can be accounted for by the force that the rod exerts on the bead. We hope that going through this exercise would help students to get more comfortable with understanding problems in a similar mould.

A simple method is described for measuring liquid density based on stretching of the spring and equilibrium of weight and elastic force. The method involves placing a container with liquid under test on the spring causing a stretch of the spring that is directly proportional to the weight of the liquid. With this technique, the liquid density can be determined without measuring its mass and volume, and it should help students comprehend the concept of density more easily. The design of the measuring setup in this study is made using tools and materials that are simple and easy to obtain, such as spring, ruler, and small plastic or metallic container (tube). Two liquids used to test the measuring method were ethanol and glycerol. A test showed that the density of the test liquids at room temperature could be measured with the relative uncertainty of 3%, hence the reliability of the described method was confirmed.

When a new topic is introduced in the curriculum, teachers seek various ways to teach students the related concepts. For the novel topic 'materials' in the revised Dutch curriculum, I developed an experiment in which students determine Young's modulus using a guitar string. The experiment not only covers several concepts related to 'materials' it also provides a clear link to the physics of music and illustrates to students, aged 16, why the topic 'materials' could be of interest.

Einstein's relation between mass and energy is perhaps the most famous equation of Physics. Despite its simplicity, the meaning of ${E_0} = m{c^2}$ is not easy to grasp. Furthermore, its traditional derivations rely either on the integral of momentum, on properties of electromagnetic radiation, or even on the expression for transformation of energy. In the present work, we provide a simple thought experiment with an inelastic collision between two particles observed from two inertial reference frames. We show that for the conservation of relativistic momentum to hold, the mass of the system must increase after the collision. We also show that the increase of mass relates to the loss of kinetic energy according to the equation ${{\Delta }}K = - {{\Delta }}m{c^2}$, which enables us to define the equation for relativistic energy ($E = m{c^2}/\sqrt {1 - {v^2}/{c^2}}$), rest energy (${E_0} = m{c^2})$ and relativistic kinetic energy ($K = E - {E_0})$. There are two main advantages in this presentation: first, it relies only on simple algebra, not depending on differential calculus and on any property of radiation; second, it leads directly to a comprehensible physical meaning of the relation of equivalence, which can sometimes be too obscure in more formal derivations.

Research has identified several students' misinterpretations of the principles of the photoelectric effect (PE). Students cannot interpret the formula using the graph's context despite the linear dependence inherited in it. Many studies pointed out that the graphical representation of kinetic energy of the ejected electrons versus frequency of incident photons is unclear when a blend of mathematical and scientific reasoning is applied. While research suggests various ways to help improve the understanding, little attention is given to the algebraic structure of the equation ${K_{{\text{Max}}}} = hf - {W_{\text{o}}}{ }$ and its corresponding graphical representation. Detailed scrutiny revealed that some phases of the PE's algebraic expression do not support its visual representation. This paper suggests a more consistent alignment of the rules of mathematics with the PE process. This suggestion emerged as an alternative algebraic representation of the law of conservation of energy in the form of a piecewise linear function. It is hypothesized that such covariational relation between photons' frequency and the ejected electrons' kinetic energy is more consistent with observable phenomena behaviour and students' mathematics knowledge. While formulating the law of conservation of energy, a physics simulation, The Photoelectric Effect (http://phet.colorado.edu), was used. The process of mathematical modelling of the PE that concluded with a covariational relation of the kinetic energy of ejected electrons was delivered to a group of 20 (N = 20) high school physics students. A didactical outline of the instructional unit is included.

Books: Clare Thomson reviews Not Necessarily Rocket Science by Kellie Gerardi.

Rick Marshall reviews How to Make the World Add Up. Ten Rules for Thinking Differently About Numbers by Tim Harford, and The Sun: A Very Short Introduction by Philip Judge.

David Sang reviews The Physics Book, foreword by Jim Al-Khalili.

Ruth Wiltsher reviews The End of Everything (Astrophysically Speaking) by Katie Mack.

Peter Main reviews Extraterrestrial by Avi Loeb.

Equipment: John Kinchin reviews Pasco Wireless Sound Sensor

The human ears are wonderful detectors, and sound gets to them in many different ways. This 'what happens next?' briefly examines two experiments which are informative in the ways in which sound travels and is heard.