Table of contents

The major space programmes permit both active and passive participation by schools. They provide numerous illustrations for traditional science courses and a basis for examination questions. Active participation involves observation of satellites by visual, photographic and radio methods. Radio signals exhibit the Faraday and Doppler effects on a grand scale. Systematic observations of signals from Cosmos satellites have led to many deductions about the purpose and behaviour of the 8 day reconnaissance satellites and to the disclosure of the location of an unannounced launch site.

For seven weeks of the final year in an honours degree course, students have devoted the whole of their time to a new type of study course. They worked, in groups of about twenty-five, on a particular theme or topic in physics. The study proceeded by a variety of informal discussions in groups or sub-groups, student lectures, written essays, individual and group attempts at problems and laboratory investigations. Formal lectures by staff members played only a small part in the teaching process. Performance was assessed on the course work and without a written examination. The students' response was excellent and the method appears to have given them a taste of and a taste for professional work in physics.

For Pt. I see Ref. School Science Review, Vol.49, p.553, 1968. The concept of e.m.f. is further discussed together with the relationships between e.m.f., potential difference and voltage. Finally suitable ways of introducing these concepts at different educational levels are discussed.

Many students identify atomism with `the' atomic theory, and consider the truth of the latter established. Textbooks list successes of the atomic theory in classical physics and chemistry. How, then, could outstanding scientists, such as Ostwald and Mach, at the turn of the century, deny the existence of atoms? The best answer is given by these anti-atomists themselves. Their controversy with Boltzmann and Planck illustrates general points in the study of the history and philosophy of science. One argument, the irreversibility paradox, is not resolved satisfactorily to this day. This is Part II of an article, the first part of which appeared in the September issue of Physics Education.

Some of the main features of the initiation and propagation of fracture in glass are described. The common flaws which limit the strength of ordinary samples of glass are illustrated. The characteristic structure of tensile fracture surfaces and some properties of the moving crack are discussed.

A study of university success and failure has been made for a sample of approximately 400 students from nine university institutions who entered honours physics courses in 1964. Their careers have been followed for the length of the normal university course of three years and it was found that there were considerable variations in the success rates for different institutions. Taking the sample as a whole, 74% obtained degrees in physics and 4% in other subjects, while 16% had left university without a degree and 7% had been delayed, but were still at university. The figures suggest that failure rates in physics are now substantially higher than they were five years ago.

During the last decade much interest has been shown in various methods of direct conversion of heat into electricity. The advantages of direct-conversion devices are discussed and the basic physical principles of thermoelectric conversion and thermionic conversion are explained. A review is given of the present state of knowledge and an assessment is made of prospects for future applications of direct-conversion devices.