In a spiral galaxy, the stars move in a circular motion around the galactic center, and the relation between velocity and the orbital radius is referred to as the rotation curve. Previous astronomical observation data indicate that the rotation curve is flat at the periphery of the galaxy, which completely dissatisfies Keplerian decline. Assuming…

The transfer of electrical energy without any electric leads or cables is not only a modern subject of research, but the technology has already found its way into our daily lives. Especially in consumer electronics a lot of applications are commercially available, mostly non-contact charging applications for toothbrushes, mobile phones, etc. On…

The present study explores students' understanding of calculus-based kinematics (henceforth, CBK), in which argumentation is taken as the sequence of the modes of fostering reasoning and problem-solving. The investigation stresses the importance of arguments students bring to the learning situation of CBK and recognizes the active construction of…

Optical fibre communication enables the global internet, but few youths ever learn about how it works, even at a basic level, until tertiary education. While some middle school curricula might include simple geometrical optics concepts like reflection and refraction, they often lack contextual linkage to worldwide telecommunications. Through our…

The air drag constant for different nose shapes of projectiles is determined with the help of a simple method combining a projectile launcher, video tracking technique and spreadsheet computer code for simulating the motion. A projectile launcher with low-cost components is developed to study air drag in projectile motion. The launcher is based on…

The Rasch model is a probabilistic model which describes the interaction of persons (test takers or survey respondents) with test or survey items and is governed by two parameters: item difficulty and person ability. Rasch measurement parallels physical measurement processes by constructing and using linear person and item measures that are…

This research aimed to measure the coefficient of restitution (COR) for tennis and golf balls using smartphone sensors. The ball and smartphone were attached at the ends of a long plastic strip: one end was a pivot with the attached smartphone and another end was for the attached ball. The ball on the plastic strip was swung to bounce the ball.…

In this work we describe a teaching proposal to calculate the eccentricity of the Moon's trajectory by applying a geometrical technique. The values of the ratios between the Earth-Moon distance and the diameter of the Moon at apogee and at perigee were calculated from a kinematic model associated with a geometrical technique of image analysis. The…

Measuring magnetic induction is occasionally performed by our students during their academic training in physics. Among the various methods used to measure it, the Hall effect is the most common and widespread. Another way consists of employing an electronic flux-meter. It is constituted by a small flat coil (SFC) connected to the input of an…

A planetarium is an invaluable tool for teaching introductory astronomy, but one that few astronomy educators have ready access to. Here we describe a do-it-yourself planetarium that can be built with modest funding. There have been other planetarium construction projects described in the literature and online, most of which use cardboard to make…

Traditionally, multiple choice assessments are graded in a dichotomous manner, where selecting the correct option for a question awards 1 point and the selection of an incorrect option awards 0 points. As a result of this grading scheme, all incorrect response options are treated as being equally incorrect regardless of potential differences in…

The phenomenon of emerging water jets from the holes of containers has been extensively studied; nevertheless, it continues to inspire researchers and teachers. The main aspects of the recent studies concern: the range of the jets trajectories; the extension of Bernoulli's equation, of which Torricelli's expression represents an ideal situation,…

We describe four classical undergraduate physics experiments that were done with everyday objects and low-cost sensors: mechanical oscillations, transmittance of light through a slab of matter, beam deformation under load, and thermal relaxation due to heat loss. We used these experiments to train students for experimental homework projects but…

Some introductory physics courses begin where student interest is thought to be highest--in waves, sound, and light--before speed, velocity, and acceleration. For students with math difficulties, this order makes sense. But most physics courses, including the author's own, begin with a study of motion. Why? Mostly due to tradition, he admits. When…

Before students learn Kirchhoff's rules, they are typically taught how to solve "combined series-parallel" circuits. The method presented in many textbooks begins by drawing a series of simplified circuits, replacing series and/or parallel elements with their equivalent resistances, eventually reducing the circuit to a voltage source and…