The study of motion is central in physics education and has taken many forms as technology has provided numerous methods to acquire data. For example, the analysis of still or moving images is particularly effective in discussions of two-dimensional motion. Introductory laboratory measurement methods have progressed through water clocks, spark…

A simple charge indicator with bipolar transistors is described that can be used in various electrostatic experiments. Its behaviour enables us to elucidate links between 'static electricity' and electric currents. In addition it allows us to relate the sign of static charges to the sign of the terminals of an ordinary battery. (Contains 7 figures…

An interdisciplinary and engaging practical is detailed which offers great versatility in the study of a qualitative and quantitative metabolism of azo-dyes by "Staphylococcus aureus". This practical has broad scope for adaptation in the number and depth of variables to allow a focused practical experiment or small research project. Azo-dyes are…

According to the hypothesis of a scalar property for time, the variability to time ratio should be constant. Three experiments tested the validity of this hypothesis in a restricted range of durations (standard values = 1, 1.3, 1.6, and 1.9 s). In each experiment, time intervals to be discriminated, reproduced, or categorized were presented with…

The uncanny valley--the unnerving nature of humanlike robots--is an intriguing idea, but both its existence and its underlying cause are debated. We propose that humanlike robots are not only unnerving, but are so because their appearance prompts attributions of mind. In particular, we suggest that machines become unnerving when people ascribe to…

The paper is about the appearance of space charge in an ohmic conductor moving in a magnetic field, as pointed out in this journal by Lorrain (1990 "Eur. J. Phys." 11 94-8) and earlier by van Bladel (1973 "Proc. IEEE" 61 260-8). The phenomenon is reinvestigated here in the light of energy balance considerations, in the particular case of a…

To account for the findings obtained in voluntary task switching, this article describes and tests the chain-retrieval model. This model postulates that voluntary task selection involves retrieval of task information from long-term memory, which is then used to guide task selection and task execution. The model assumes that the retrieved…

Recent research has demonstrated that knowledge of real-world events plays an important role in guiding online language comprehension. The present study addresses the scope of event knowledge activation during the course of comprehension, specifically investigating whether activation is limited to those knowledge elements that align with the local…

Five experiments were conducted to examine how unsuccessful retrieval influences learning and subsequent memory. We used a cued-recall paradigm that produces many unsuccessful retrieval attempts (followed by feedback) and allows comparisons to be made between later memory for these trials and trials that only required reading or studying the…

In three experiments, we evaluated remembering and intentional forgetting of attitude statements that were either congruent or incongruent with participants' own political attitudes. In Experiment 1, significant directed forgetting was obtained for incongruent statements, but not for congruent statements. In addition, in the remember group, recall…

Skidmore and Thompson (this issue of "Educational Researcher") imply that a graph was changed with the intent to promote more experimental research in education. In this response, the author presents evidence that challenges this implication and concludes that the changed graph does not accurately capture the "declining" trend of experimental…

In a word learning experiment, 14- and 18-month-old infants are tested on their perceptual sensitivity to coda-consonant omissions. The results indicate that 14-month-olds are not sensitive to coda consonant omissions, showing a parallel with the omission of target coda consonants in early child language productions. At 18 months, infants are…

Light is the origin of vision. The pattern of shading reflected from object surfaces is one of several optical features that provide fundamental information about shape and surface orientation. To understand how surface and object shading is processed by birds, six pigeons were tested with differentially illuminated convex and concave curved…

How do people decide which claims should be considered mere beliefs and which count as knowledge? Although little is known about how people attribute knowledge to others, philosophical debate about the nature of knowledge may provide a starting point. Traditionally, a belief that is both true and justified was thought to constitute knowledge.…

This study outlines a new explanation for homophily in social networks that is neither intended nor imposed by constraints on partner choices. Rather, homophily is an endogenous product of the emergent exchange process, in which actors seek high-value partners who reciprocate their gestures. Whereas all actors initially direct exchange toward…