Learning to walk leads to an increase in language abilities; however, the underlying mechanisms accounting for this relation remain unclear. Investigating the quality of early gait control may offer some insights. The purpose of this study was to: (1) quantify how 13-month-olds (n = 39; 39% male) and 24-month-olds (n = 39; 59% male) adapt gait…

In a recent paper (Denny 2002 Eur. J. Phys. 23 449-58), entitled "The pendulum clock: a venerable dynamical system", Denny showed that in a first approximation the steady-state motion of a weight-driven pendulum clock is shown to be a stable limit cycle. He placed the problem in a historical context and obtained an approximate solution using the…

Kids are drawn to dolls and dump trucks, and crashing the two together might just be a child's favorite pastime. Who knew such a simple pleasure could serve as an accessible, compelling phenomenon for instigating investigations of force and motion. With a few inexpensive materials straight out of the toy box (literally, a doll, a dump truck, a…

The question from the title is raised because in almost all introductory physics courses/textbooks the atmospheric pressure has been attributed to the weight of the column of air from a given level in the atmosphere up to its top. "Air is pressing on air." However the same textbooks, in the chapter on the kinetic theory of gases, tell…

Atwood invented a machine in the 1780s that enabled him to observe the motion of a falling body as slowly as desired. This machine was equipped with the necessary means to measure the distance covered by the body and the time taken. With this data, it was possible, in addition to studying the falling motion, to calculate the local gravitational…

The objective of this work was to highlight the conceptions of force held by students aged 10-17 years old, in situations where animate and inanimate objects interact. In the proposed experimental situations, we varied parameters such as the motion and position of an object and the agent's effort. We asked questions about both inanimate and…

Various developmental studies have demonstrated that implied object weight is a key variable in children's interpretations of motion, such as predicting the objects' speeds. An additional bias in predictions of object motion is representational momentum (RM), where objects are anticipated to be found in a location farther along in the direction of…

The pendulum was an important scientific instrument in the 17th century. It became a typical textbook problem in the 18th century. After the introduction of vectors in physics in the 1890s, the pendulum problem started to be progressively solved in the manner we know nowadays from introductory mechanics courses. Starting from "F = ma"…

Resistance training has become a preferred method for developing muscular strength among various populations. A variety of resistance training modes are available, but there are mixed outcomes regarding strength development among barbells, dumbbells, and weight machines. The purpose of this study was to investigate the differences in strength…

G. P. Bingham, R. C. Schmidt, and L. D. Rosenblum (1989) found that, by hefting objects of different sizes and weights, people could choose the optimal weight in each size for throwing to a maximum distance. In Experiment 1, the authors replicated this result. G. P. Bingham et al. hypothesized that hefting is a smart mechanism that allows objects…

Using a mixed methods approach, we explore a relationship between students' graph reasoning and graph selection via a fully online assessment. Our population includes 673 students enrolled in college algebra, an introductory undergraduate mathematics course, across four U.S. postsecondary institutions. The assessment is accessible on computers,…

We study the variation of the apparent weight of an object with height above the surface of a planet with a (buoyant) atmosphere. Interestingly, this variation depends on two competing factors--the reduced gravitational acceleration (which acts to reduce the weight with increasing height) and the reduced buoyancy force in the progressively less…

Describes the result of dropping objects of similar size and shape but of differing weight through air. Compares ideas on motion of Galileo and Aristotle. (GH)

The aging process happens during an individual's lifespan. Everybody is involved in this process and none can escape it. Almost half the community where old individuals dwell report daily pain, which mostly concerns pain in muscles and joints. Joint pain often affects functioning, in terms of mobility, functional independence, participation in…

Engaging in healthy daily 24-h movement behaviors (e.g., moderate-to-vigorous physical activity [MVPA] [greater than or equal to] 60 minutes, screen time <2 hours, and sleep [greater than or equal to] 7 hours) is suggested to be associated with favorable mental health outcomes (e.g., less depressive symptoms and higher quality of life). Given…