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The author examines the state-of-the-art of practical work assessment in school level physics. He discusses the main objectives of the GCSE National Criteria in overcoming past trends in assessment and achieving differentiation of candidates.

The proposed introduction in September 1986 of a system of examinations to replace the present GCE O-level and CSE will impose on teachers the responsibility for a significant proportion of the assessment of their pupils. In addition, the adoption of the National Criteria for GCSE means that there will be some degree of commonality imposed on all physics syllabuses and schemes of assessment. One of the requirements of the criteria is that all examinations at this level will include an assessment of practical skills in the laboratory and that this will be carried out by the teacher. The introduction of a compulsory assessment of practical and experimental skills for all candidates, together with the requirement that this should be, at least in part, the assessment of practical work carried out as part of the course, is a source of concern for many teachers. The author outlines the schemes of practical assessment, which have been accepted by the SEC as meeting the National Criteria, showing how they develop from the relevant objectives in the criteria, and suggests how teachers might begin to produce their own assessment programme.

Advanced-level physics (Nuffield) investigations consist of short experimental projects which are carried out by students in the second year of the course. Each student selects a topic for study, either independently or with some advice from a teacher, and then, during a prescribed period, carries out experimental work which is subsequently written up and assessed by the teacher or teachers. The prescribed time for carrying out the whole exercise is around 20 hours and, in this time, the candidates are expected to prepare for the project, devise and carry out experiments, analyse the data and then complete a written account. The author gives an account of the assessment criteria used.

For some years there has been a growing recognition of the need for changes in assessment patterns in school science. These changes include a move towards criterion-based assessment linking to objectives and an increased emphasis on the assessment of practical and experimental skills. These changes are, to a significant extent, embodied in the new GCSE assessment schemes and will thus affect all students and teachers of physics from September (1986). At least 20% of the total assessment in GCSE physics examinations must be of practical and experimental skills, and at least half of this must be carried out in the laboratory environment. One development which addresses the needs and problems outlined above is the science component of OCEA, the Oxford Certificate of Educational Achievement. Because this covers a much wider field than assessment of practical and experimental skills in physics, a brief description of the whole project is given.

The author gives an account of the life and work of Niels Bohr.

At South Glamorgan Institute of Higher Education physics is taught over a wide range of courses. In addition to the more conventional courses found in science, technology and education faculties there is a physics input into areas such as beauty therapy, applied biology, catering, chiropody, dental technology, environmental health, food technology, hairdressing, human-movement studies, industrial design, applied life sciences, marine technology, medical laboratory science, physiological measurement, nursing and speech therapy. Due to the fundamental differences in emphasis required when teaching physics as a 'minor' subject on these types of courses, and since the authors have no courses which lead to a 'major' physics qualification, it is necessary to develop a rational strategy for teaching physics as a 'service' subject. If this is not achieved then staff satisfaction and student interest are likely to suffer. They describe their strategy.

Erwin Schrodinger first described the thought-experiment which has since become known as 'the paradox of Schrodinger's cat' 51 years ago. In recent years, popular accounts of quantum mechanics have tended to adopt one or other of the philosophically most extreme solutions to this paradox, i.e. the consciousness hypothesis or the many worlds interpretation. The author attempts to redress the balance by describing what he takes to be the orthodox solution to the paradox which explains the paradox, without recourse to such counterintuitive notions as a cat simultaneously dead and alive or a universe continually splitting into multiple worlds, as being due to a misapplication of the quantum formalism.

'Computational physics' is a recently developed optional course involving practical work taken by physics undergraduates at the University of Birmingham. The course includes an introduction to numerical methods and their use in physics. Topics covered include the fast Fourier transform, nonlinear least-squares fitting, Monte Carlo methods applied to the Ising model, and the solution of the restricted three-body problem using a Runge-Kutta method. Throughout the course emphasis is placed on the value of graphical displays. The article is a description of the course.

In optically anisotropic fibres, the refractive indices for plane polarised light vibrating parallel and perpendicular to the fibre axis and the birefringence are parameters that characterise the structure of the materials on the molecular level. Objects in optical microscopy can be classified as amplitude or phase. Amplitude objects vary in their light absorption with respect to the medium that surrounds them, thus exhibiting a certain amount of natural contrast. In interference microscopy, phase objects are of special interest. These objects produce no variations in the light being absorbed and differ from the surrounding medium merely by their refractive indices or thicknesses. Using a double-beam interference microscope, e.g. the Pluta polarizing interference microscope, one can determine the mean refractive indices and birefringence of the fibre.

A common problem encountered during introductory courses on electricity and magnetism is that of the motion of charged particles in electric fields. Textbooks often describe the paths of moving charges in constant fields or in the field due to a single charge. However the question of the motion of charges in fields due to an arbitrary arrangement of charges is seldom addressed. A microcomputer can be used to determine the electric field at a point in the vicinity of a fixed array of charges (Kirkup 1985). In consequence the acceleration of a charged particle at a point within a field may be found and hence its path determined. The author describes the implementation of a trajectory-plotting program on a microcomputer and shows how it may be used to demonstrate, for example, the focusing effect of a simple electrostatic lens.

We apologise for a small error in the report of the Teachers of Physics awards (Physics Education May 1986 p131). The recipients were in fact presented with Caithness Glass paperweights, not Waterford paperweights.