Many derivations of the relativistic addition law of parallel velocities without use of the Lorentz transformations (LT) are known. Some of them are based on thought experiments that require knowledge of the time dilation and the length contraction effects. Other derivations involve the Doppler effect in the optic domain considered from three…

From its inception, performance in the sport of gymnastics has relied on the laws of physics to create movement patterns and static postures that appear almost impossible. In general, gymnastics is physics in motion and can provide an ideal framework for studying basic human modeling techniques and physical principles. Using low-end technology and…

Consider a problem of sliding blocks, one stacked atop the other, resting on a frictionless table. If the bottom block is pulled horizontally, nature makes a choice: if the applied force is small, static friction between the blocks accelerates the blocks together, but with a large force the blocks slide apart. In that case, kinetic friction still…

A simple electric motor has a problem in that the current applied to the motor per se can rarely trigger its rotation. Usually such motors begin to rotate after the rotor is slightly turned by hand (i.e., manual starting). In a "self-starting" motor, the rotor starts to rotate spontaneously as soon as the current is applied. This paper describes…

This paper investigates the role of static and dynamic attributes for the animate-inanimate distinction in category-based reasoning of 7-month-olds. Three experiments tested infants' responses to movement events involving an unfamiliar animal and a ball. When either the animal or the ball showed self-initiated irregular movements (Experiment 1),…

The purpose of this study was to diagnose the misconceptions held by pre-service physics teachers about force and motion. The secondary aim of the study was to detect whether misconceptions vary according to gender, educational level, and culture. The study was conducted with 79 student-teachers attending to one of the largest faculties of…

The authors describe a new visual illusion first discovered in a natural setting. A cyclist riding beside a pair of sagging chains that connect fence posts appears to move up and down with the chains. In this illusion, a static shape (the chains) affects the perception of a moving shape (the bicycle), and this influence involves assimilation…

Three experiments utilizing a 14-element arm movement sequence were designed to determine if reinstating the visual-spatial coordinates, which require movements to the same spatial locations utilized during acquisition, results in better effector transfer than reinstating the motor coordinates, which require the same pattern of homologous muscle…

As one of the recognized media of the Orff-Schulwerk method of music instruction, movement is fundamental to music specialists' teaching. It can embody the mantra of "sound before sign," and provide the means by which students experience the kinesthetic learning that is so natural to their musical development. Because there are multiple…

Twenty-nine Zulu-speaking primary school teachers were enrolled for a certificate in-service science education course. Initially, informal classroom discussions with these teachers pointed out poor conceptual knowledge in basic astronomy. This study investigated teachers' scientific and indigenous conceptions of the Earth-Moon-Sun (E-M-S) system,…

In this article, I will extend the falling ball method to measure the viscosity of liquids regardless of the degree of their viscosity. For this, I will show that one can obtain a measurement of the terminal velocity of a falling spherical ball in a viscous liquid by solving numerically the equation of motion which describes the dynamics of the…

Physical educators should be able to define the "correct form" they expect to see each student performing in their classes. Moreover, they should be able to go beyond assessing students' skill levels by measuring the outcomes (products) of movements (i.e., how far they throw the ball or how many successful attempts are completed) or counting the…

To locate objects in the environment, animals and humans use visual and nonvisual information. We were interested in children's ability to relocate an object on the basis of self-motion and local and distal color cues for orientation. Five- to 9-year-old children were tested on an object location memory task in which, between presentation and…

Data from speed skating during World Cup 1,500-m middle-distance races were analyzed to (a) determine the time/velocity distribution during the race and (b) assess the impact of time spent in several race sectors on performance outcome. Absolute and relative sector times for the first 300 m (S1) and the following three 400-m laps (S2-S4) and their…

We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)