Table of contents

Science on Stage: Science in Action competition hits the heights in Madrid Conference: New year brings ASE conference Exhibition: BETT 2007 sells hard and plays hard

No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

The question that has no answerGary Williams

In this article, the teaching of electrostatics at university level is described, with reference to observations first recorded by the Ancient Greeks, early industrial applications and modern-day bioelectrostatic technology.

This article surveys our understanding of electric charge from Coulomb's day to the present.

A teaching sequence based on the use of microscopic models to link electrostatic phenomena with direct currents is presented. The sequence, devised for high school students, was designed after initial work carried out with student teachers attending a school of specialization for teaching physics at high school, at the University of Pavia. The results obtained with them are briefly presented, because they directed our steps for the development of the teaching sequence. For both the design of the experiments and their interpretation, we drew inspiration from the original works of Alessandro Volta; in addition, a structural model based on the particular role of electrons as elementary charges both in electrostatic phenomena and in currents was proposed.

The teaching sequence starts from experiments on charging objects by rubbing and by induction, and engages students in constructing microscopic models to interpret their observations. By using these models and by closely examining the ideas of tension and capacitance, the students acknowledge that a charging (or discharging) process is due to the motion of electrons that, albeit for short time intervals, represent a current. Finally, they are made to see that the same happens in transients of direct current circuits.

This article presents a review of the forgotten history of the doubler of electricity, which by the end of the 18th century was the first apparatus used for the generation of electricity without using friction. Several examples are described, including a new one for a rotating doubler developed as an electrostatic generator.

Some difficulties that students face with two-dimensional motion are addressed. The difficulties addressed are the vectorial representation of velocity, acceleration and force, the force–energy theorem and the understanding of the radius of curvature.

When students begin the study of Newton's laws they are generally comfortable with static equilibrium type problems, but dynamic examples where forces are not constant are more challenging. The class exercise presented here helps students to develop an intuitive grasp of both the position–velocity–acceleration relation and the force–acceleration relation. Further analysis of the demonstration is used to verify the impulse–momentum relation and it can be used as a starting point for discussing energy issues in the jump.

This paper aims to supplement the scant literature on the history of ideas about the nature of sound. It presents how notions about the production and propagation of sound developed from antiquity up to the 17th century, i.e. from the time of Pythagoras to the time of Sauveur. It will highlight and examine the principles of sound that were formulated by Galileo and Newton, which are among the less well known work of these two giants in physics. The contributions of some familiar scientists, for example Hooke and Boyle, who are usually associated with scientific discoveries unrelated to sound, will also be covered. Some insights for the understanding of the nature of science and for the teaching and learning of physics will also be presented.

We describe a physics investigation project inspired by one of the adventures of Odysseus in Homer's Odyssey. The investigation uses the laws of mechanics, vector algebra and a simple way to construct a fan-and-sail-cart for experimental verification.

We describe an experimental set-up that is very easy to construct but which produces an unusual phenomenon which verifies Archimedes' law for gas.

The investigation of the focusing in fish eyes, both theoretical and experimental, by using a simple fish eye model, provides an interesting biological context for teaching the introductory principles of optics. Moreover, the students will learn concepts of biology by an approach of cause and effect.

We offer two new experiments concerning the experimental verification of Boyle's law and the ideal gas law. To carry out the experiments we use glass tubes, water, a syringe and a metal manometer. The pressure of the saturated water vapour is taken into consideration. For educational purposes, the experiments are characterized by their accessibility and the considerable precision of results.

Many researchers and lecturers have reported that the concept of the mole and Avogadro's number are frequently misunderstood by first-year science students. For this reason, it is highly recommended to introduce this fundamental number to high school and freshman science students as clearly as possible. Therefore, it is pedagogically very useful to diversify the methods of determination of Avogadro's number which are based on basic physics phenomena accessible to those classes of students. Along these lines, I will describe here an unusual method based on the classical Hall effect for determining Avogadro's number. The present method is not relevant for its accuracy but mainly for its simplicity and its 'cleanness' compared to the usual electrochemical method used at this instruction level. In addition, this method provides an extra useful test for the validity of the free electron model.

We describe a simple apparatus capable of showing the magnetic phenomena for a current-carrying circular coil quantitatively.

INTERVIEW Lightning strikes in BostonMichael Alexander, the director of public programs at the Boston Museum of Science, talks to David Smith about how to deal with issues and subjects that are difficult to present using more traditional museum methods.

WE RECOMMEND

LogIT Lab, Voyager, DataVision CX and SensorLink LogIT dataloggers offer flexible and affordable logging.

Low Voltage Water Pump This pump is ideal for schools to use in water-based projects.

Einstein's Nobel Prize: A Glimpse Behind Closed Doors Uncovering the trail of how Einstein won a Nobel prize.

Not Even Wrong This book deals with how the scientific community really works.

WORTH A LOOK

The Prestige This is a dazzling film about the rivalry between two magicians.

HANDLE WITH CARE

Angel Flames The candles aren't much use in the lab – better on a cake.

WEB WATCH A collection of websites related to electrostatics.

Conceptual change requires insight and interventionMaja Planinic

How the 2005 World Year of Physics changed my lifeUlrike Regner