Table of contents

The link between trigonometry and forces can be a conceptually difficult one for some A-level students. This article describes a simple, practical investigation that students can carry out using three force metres to find the horizontal and vertical components of forces.

What trajectory does a marble follow if it is held inside a rotating pipe and then suddenly released?

This study presents a revised version of an old experiment available in many textbooks for measuring the speed of sound in air. A signal-generator application in a smartphone is used to produce the desired sound frequency. Nodes of sound waves in a glass pipe, of which one end is immersed in water, are more easily detected, so results can be obtained more quickly than from traditional acoustic experiments using tuning forks.

There are many examples on the internet of videos of 'pendulum wave machines' and how to make them (for example, www.instructables.com/id/Wave-Pendulum/). The machine is simply a set of pendula of different lengths which, when viewed end on, produce wave-like patterns from the positions of the bobs. These patterns change with time, with new patterns emerging as the bobs change phase. In this article, the physics of the machine is explored and explained, along with tips on how to build such a device.

The phenomena of free-fall weightlessness have been demonstrated to students for many years in a number of different ways. The essential basis of all these demonstrations is the fact that in free-falling, gravitationally accelerated systems, the weight force and weight-related forces (for example, friction and hydrostatic forces) disappear. In this article, an original electrostatic demonstration of weightlessness is presented. A charged balloon fixed at the opening of a plastic container cannot lift a light styrofoam sphere sitting on the bottom when the container is at rest. However, while the system is in free-fall, the sphere becomes weightless and the charged balloon is able to lift it electrostatically.

I report on the opening ceremony of the International Year of Light and Light-based Technologies 2015 (IYL2015), which took place at the UNESCO headquarters in Paris, France, on 19–20 January 2015. Over the two days, more than 1000 participants from all over the world learned more about the fundamental properties of light and advanced photonics applications, the history of optics and its applications through the centuries, light poverty and light pollution, and light for everyday life, health and research.

This article describes an alternative method to determine the refractive index of transparent liquids. The method only requires a laser pointer, a ruler and a modified fish tank.

Many icebergs are vulnerable to capsizing. In doing so the gravitational potential energy of the ice is increased, while that of the displaced sea water is decreased. Applying the principle of the conservation of energy shows that by capsizing, there is also a net transfer of energy to the surrounding sea water. This will be a maximum for a particular iceberg geometry. For many iceberg geometries the energy transfer can be measured on the scale of nuclear explosives. Three teaching opportunities suggested by the analysis are outlined.

Creativity can be viewed from different perspectives, such as the creative thinking process, the product, the creative environment and the individual. The physics domain, which is based on experiments, research, hypotheses and thinking outside the box, can serve as an excellent grounding for creativity development. This article focuses on creative thinking in physics textbooks. Creative thinking includes divergent thinking, which consists of four core components: fluency, flexibility, novelty and elaboration. The purpose of our study is to understand whether and how physics textbooks (such as the Israeli high-school book Newtonian Mechanics) enable the promotion and development of creative thinking. Findings indicate that they do not, so there is a need to raise physics teachers' awareness of the importance of creative thinking in learning materials. It is advisable for physics teachers to engage in professional development courses in appropriate teaching strategies for the development of this creativity.

The Scratch online authoring tool, which features a simple programming language that has been adapted to primary and secondary students, is being used more and more in schools as it offers students and teachers the opportunity to use a tool to build scientific models and evaluate their behaviour, just as can be done with computational modelling programs. In this article, we briefly discuss why Scratch could be a useful tool for computational modelling in the primary or secondary physics classroom, and we present practical examples of how it can be used to build a model.

We use apparatus based on two Geiger–Müller tubes, a simple electronic circuit and a Raspberry Pi computer to illustrate relativistic time dilation affecting cosmic-ray muons travelling through the atmosphere to the Earth's surface. The experiment we describe lends itself to both classroom demonstration to accompany the topic of special relativity and to extended investigations for more inquisitive students.

A very old and well-known magical trick is the so-called tablecloth pull. A table is covered with a tablecloth, on top of which are certain objects. The task is to remove the tablecloth while the objects—which must not be touched—stay on top of the table. This article describes the physics behind the experiment, and presents examples recorded with high-speed cameras.

This study is about the dynamics of a sliding ladder leaning against a vertical wall. The results are understood by considering the motion divided in two parts: (i) for $0\leq t\leq {{t}_{s}}$ with one degree of freedom, and (ii) for $t>{{t}_{s}}$ with two degrees of freedom, where the separation is determined by the instance ${{t}_{s}},$ when the ladder loses its contact with the wall. The observed experimental details are explained by appealing a simple model based on elementary notions of mechanics. We emphasize some features, such as a maximum of the x component of the velocity and of the acceleration of the centre of mass in the first part, and a minimum of the normal reaction force on the floor in the second.

The bounce of a ball is a seemingly innocuous event that can be used to illustrate many aspects of elementary and even advanced mechanics. Both normal and oblique bounces on a rigid surface are considered in this article, emphasizing qualitative features of the bounce process. If the ball bounces at an oblique angle then it can slide throughout the bounce, or just at the start of the bounce, and may even slide backwards at the end of the bounce. A ball can also grip the surface after a short sliding phase, or it can grip right from the start. When the ball grips, static friction rather than sliding friction determines the rebound speed, spin and angle.

This paper provides the formula for the elevation angle at which a projectile has to be fired in a vacuum from a general position to hit a target at a given distance. A spreadsheet application that models the trajectory is presented, and the problem of finding the points of shot and impact of a projectile moving in a vacuum if three points of the trajectory are known is solved and modelled by another interactive application. A Gaussian elimination method is used to solve the system of linear equations that gives the trajectory parameters. These applications were developed with 30 high-school students, who were given a questionnaire to find out their opinion of the lessons.

Wind musical instruments are affected in their intonation by temperature. We show how to account for these effects in a simple experiment, and provide results in languages accessible to both physics and music professionals.

A student realizes that a point particle that is able to rise at a given point P₀ at height H when launched vertically from the origin O of a Cartesian plane at a fixed initial speed V₀ cannot reach, by means of a direct shot from a small spring cannon, a point P positioned at the same height H and distance d from P₀, with 0 < d ≤ R, where R is the maximum horizontal distance attainable with an optimum throw at an angle of 45°. However, the student realizes that, in the absence of air resistance, conservation of energy does not prevent this possibility. Therefore, in order to reach point P, the student uses a perfectly reflecting surface, opportunely inclined with respect to the horizontal. The full story of how this is done will be narrated in this article.

Improving the scientific literacy of non-scientists is an important aim, both because of the ever-increasing impact of science on our lives and because understanding science enriches our experience of the natural world. One route to improving scientific literacy is via general education undergraduate courses—i.e. courses for students not majoring in the sciences or engineering. Because it encompasses a variety of important scientific concepts, demonstrates connections between basic science and real-world applications and illustrates the creative ways in which scientific insights develop, biophysics is a useful subject with which to promote scientific literacy. I describe here a course on biophysics for non-science-major undergraduates recently developed at the University of Oregon (Eugene, OR, USA), noting its design, which spans both macroscopic and microscopic topics, and the specific content of a few of its modules. I also describe evidence-based pedagogical approaches adopted in teaching the course and aspects of course enrollment and evaluation.

David Smith talks to Nobel Prize-winning graphene pioneer Konstantin Novoselov about his early career in Russia and his move to Manchester, where he is currently involved in setting up the National Graphene Institute.

In my article (Featonby 2015 Phys. Educ.50 256), I looked at how the behaviour of a spinning top differs when it is set to spin on a gentle incline.