Table of contents

Pupils' physics knowledge and way of thinking can be assessed by giving them marks for asking questions. This method also increases their interest in the subject and develops their imaginative thinking. Some pupils' questions are presented and discussed as examples.

This article outlines an exciting course for Women in Science and Technology. The Physics section is considered in some detail and biographies of two former students are included.

This article examines some of the difficulties students have with understanding sound. It also illustrates the need for physics teachers to examine critically aspects of inherited and fashionable teaching analogies and demonstrations before using them.

An isolated system consisting of two molecules of the same type is an unreliable guide to the behaviour of molecules in a condensed material. The forces experienced by a molecule in a material at equilibrium should not be confused with the forces needed to change the equilibrium positions themselves.

This article considers the problem of determining the angle(s) of projection for a particle to travel a prescribed distance up an inclined plane, and shows that there can be either three, two, one or no solutions to this problem, i.e. three, two, one or no possible angles of projection.

Large-scale demonstrations of the propagation of a HeNe laser beam in graded index optical media have been developed, using interdiffusing liquid layers. The sinuous paths of a ray in a GRIN optical fibre and lenses have been simulated.

An experiment is described which can be used to demonstrate quantitatively the properties of the superconductor critical current.

It is demonstrated that close visual inspection of the surface of a soap film can reveal many interesting dynamical and structural features which change with time as the bubble ages and thins.

An unexpected intense blue line appears when a white paper screen is used to demonstrate the spectral lines of a mercury lamp with a diffraction grating. The line is not present when a plastic screen is used and is due to the fluorescence of the whitening agents in the paper.

Muscle forcesJ O Linton Wolverhampton Grammar School, Wolverhampton WV3 9RB, UK

More `On an analogy for Ohm's law'Ann C Archer St Margaret's School, Bushey, Herts, UK

Fewer physics studentsM D Bakall Kingston College of Further Education, Surrey KT1 2AQ, UK

Classical origins of `E = mc²'R T Smith Business Link Ltd, Moor Lane Business Centre, Widnes WA8 7AQ, UK

Language and science in primary schoolsTim Watson 63 Fort Royal Hill, Worcester WR5 1BY, UK