Discusses the Doppler effect for relative motion between a source of waves and an observer and the orbital dynamics of communications satellites. Presents preliminary calculations of the satellite's altitude and linear velocity using only the concepts of the Doppler shift and the mechanics of motion in a circular path. (JRH)

Describes the design and working of inexpensive accelerometers that can be moved by hand on an overhead projector and give an observable indication when their acceleration equals or exceeds a certain value. (JRH)

Presents the theory behind a two-dimensional curved path along which the magnitude of the acceleration vector remains constant for an object moving frictionlessly under the influence of gravity. (JRH)

Scientific communities have established social mechanisms for proposing explanations, questioning evidence, and validating claims. Opportunities like these are often not a given in science classrooms (Vellom, Anderson, & Palincsar, 1993) even though the National Science Education Standards (NSES, 1996) state that a scientifically literate person…

The PISA assessment instruments for students' scientific literacy in 2000, 2003, and 2006 have each consisted of units made up of a real world context involving Science and Technology, about which students are asked a number of cognitive and affective questions. This article discusses a number of issues from this use of S&T contexts in PISA…

We review Brown and Kloser's article, "Conceptual continuity and the science of baseball: using informal science literacy to promote students science learning" from a Vygotskian cultural-historical and dialectic perspective. Brown and Kloser interpret interview data with student baseball players and claim that students' conceptual understanding…

Language is a complex adaptive system: Speakers are agents who interact with each other, and their past and current interactions feed into speakers' future behavior in complex ways. In this article, we describe the social cognitive linguistic basis for this analysis of language and a mathematical model developed in collaboration between…

Digital lecturing systems (computer and projector, often with PowerPoint) offer physics instructors the ability to incorporate graphics and the power to share and reuse materials. But these systems do a poor job of supporting interaction in the classroom. For instance, with digital presentation systems, instructors have limited ability to…

Classroom activities that include the process of model building, in which students build simplified physical representations of a system, have the potential to help students make meaningful connections between physics and the real world. We describe a lesson designed with this intent for an introductory college classroom that engages students in…

In this article, we describe a simple method which can be used to measure the efficiency of a low power dc motor, a motor-converted dynamo and a coupled motor-dynamo module as a function of the speed of rotation. The result can also be used to verify Faraday's law of electromagnetic induction. (Contains 1 table and 8 figures.)

Intermolecular forces and surface tension gradients in solutions lead to remarkable flows, known as Marangoni flows, where liquid flows from a region of low surface tension towards higher surface tension. Details of these flows, not visible to the naked eye, are made visible on an overhead projector owing to variation in the index of refraction.…

A simple, flexible and very low cost hardware plus software framework for developing computer-interfaced science experiments is presented. It can be used for developing computer-interfaced science experiments without getting into the details of electronics or computer programming. For developing experiments this is a middle path between…

This article presents an approach to integrate contemporary physics into high-school teaching. We present a simple way to understand mass spectroscopy using basic physics concepts, so that high-school students may have contact with recent topics of modern research. The main features of a time-of-flight (TOF) mass spectrometer using secondary…

Cross-curricular secondary instructional strategies exist in many different forms and can be applied to any two or more curricular disciplines. Most importantly, these strategies have been proven to be effective in improving learning and comprehension of important concepts across all curricular fields involved in the activity. There is no…

Video analysis of motion has been in use now for some time. However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers.…