This Electronic Edition May Be Freely Copied and Redistributed for Educational or Research Purposes Only. Series Preface Teaching Aims

It may not be soM for profit nor incorporated in any product soM for profit without the express pernfission of The Executive Secretary, International The long-term aim of the Commission on Crystallographic Teachihg in establishing this pamphlet programme is to produce a large collection of short statements each dealing with a specific topic at-a specific level. The emphasis is on a particular teaching approach and there may well, in time, be pamphlets giving alternative teaching approaches to the same topic. It is not the function of the Commission to decide on the 'best' approach but to make all available so that teachers can make their own selection. Similarly, in due course, we hope that the same topics will be covered at more than one level. The first set of ten pamphlets, published in 1981, and this second set of nine represent a sample of the various levels and approaches and it is hoped that they will stimulate many more people to contribute to this scheme. It does not take very long to write a short pamphlet, but its value to someone teaching a topic for the first time can be very great. Each pamphlet is prefaced by a statement-of aims, level, necessary background, etc. To convey in non-mathematical language, elementary concepts of symmetry in finite objects and repetitive patterns. Level This material would be suitable as an introduction for undergraduates with no previous knowledge of crystallography.