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Developing the Nuffield advanced physics course involved thought about the teaching of many areas of physics, from materials to induction motors and electromagnetic waves. This article reports on just one part of that activity: ideas concerned with the introduction of quantum ideas at various times and in various ways through the course.

Quantum theory comprises a number of physical concepts and methods of calculation applicable to bodies on an atomic scale and consequently to the explanation of the properties of macroscopic bodies in terms of the behaviour of their constituent particles. In advanced work the theory is highly mathematical, but at an elementary level the difficulties lie mostly in the appreciation of the relevant physical ideas. Wave-particle duality, indeterminacy, the nature of a quantized state of a system and the exclusion principle cause most conceptual problems.

The author discusses the possibility of introducing 'real' quantum mechanics, i.e. quantum mechanics as a predictive tool, at a much earlier point than usual-say, in the first undergraduate year, or even in the sixth form.

The measurement of the gravitational attraction of Schehallien by determining the deflection of a plumb line suspended near the mountain is described.

A simple and in most respects cheap demonstration apparatus is described. Its components can be found in most school, college and university laboratories. The article also gives a discussion of the Peltier effect and, by way of introduction to it, of the Seebeck effect, the better known thermoelectric effect, used in the measurement of temperatures by thermocouples.

At the beginning of the Autumn term 1971, some 400 students from the six PIP physics departments which combine in the Physics Interface Project took a mathematics preknowledge test, consisting of 50 multiple choice items. The question arose as to whether certain gaps in knowledge revealed by the test results were a consequence of the differences between the various GCE syllabuses taken by the candidates. This was determined by calculating a facility index which was independent of the standard of the groups used, for each item separately. It was tentatively shown that syllabus differences did occur.

Today's student is familiar with science fiction space travel in which rapid movement between stars is commonplace. They often ask just how fantastic this possibility is. This motivated consideration of the optimum space travel possibilities allowed by our present understanding of the fundamental laws of physics. It is shown that a payload ratio of 0.01 will give a trip of 8 light years in about 10 earth years, with the passengers arriving 4.6 years older than when they left earth and having experienced their normal 'weight' during the trip.

INTER NAVEX annually provides the world's largest audio-visual exhibition and conference, this year having well over a hundred stands, numerous film shows and a major daily programme of conference sessions. From the many new items of hardware and software available this year, the author selects those of most interest to the physics teacher. On the whole the theme is hardware-as indeed was that of the majority of exhibits-but particularly noteworthy software companies are mentioned too.

A simple, linear, wide range V-F converter which can be quickly constructed with two digital integrated circuits, two transistors, two capacitors and a resistor is described. Its applications are illustrated. In order to convey the simplicity of this design, and (to the author's mind) the complexity of more widely used types the principles of the latter are described first.

Apart from providing projects within acoustics, investigations on musical instruments can be used to engender ideas useful in advanced physics. At the same time, through the steadily growing absorption in music by so many young people, research projects in this field at school or university would allow the intellectual challenges which are present in studies in physics to be seen in relation to other cultural activities.

Many A level syllabuses in chemistry and physics include sections on the Bohr theory of the hydrogen atom as an introduction to atomic structure and interference in thin films, as demonstrated in the Fabry-Perot interferometer. The experiment described in this article clearly demonstrates the effect of finite nuclear mass in modifying the simple Bohr model of single electron atoms and the capability of a February-Perot interferometer to resolve spectral lines differing in wavelength by 10 nm. The experiment therefore forms a useful bridge between the subject areas of atomic physics and optics and illustrates how atomic parameters may be derived from simple macroscopic measurements.

This article describes the design and construction of an analogue computer which will solve the simultaneous differential equations governing the growth and decay of the nuclides in a simple, three member, radioactive decay chain. The instrument, which was shown at the 1973 Physics Exhibition, was constructed to provide a useful demonstration for teaching. It also provides a simple example of an analogue computer capable of solving problems of practical interest, and thus gives a useful introduction to analogue computer techniques.