ABSTRACT

The twentieth century has seen many contradictory devel­ opments in lecture demonstration. On the one hand some of the really great exponents of the art (for example Sir Law­ rence Bragg) have worked in this period, and some of the most exciting developments in technology (such as closedcircuit television, laser light sources, oscilloscopes, etc) have become available to enhance demonstrations. But, on the other hand, shortage of time, and of technical assistance, have reduced the opportunities for demonstration in the course of ordinary school or university classes. Nowadays the art tends to be fostered only for special occasions, such as Christmas lectures and popular lectures to encourage wider interest in science.