New trends in physics teaching, v.4; The ... - unesdoc - Unesco

New Trends in Physics Teaching IV
ISN'T ALL THIS TOO COMPLICATED AND EXPENSIVE FOR SCHOOLS?
It was not part of my brief to give an outline syllabus or to suggest how a course in optics might
be planned. On the contrary, the aim of this article was to try to convey something of the excitement
of modern optics and of its importance in the forefront of physics research in the hope of
persuading those much more knowledgeable than I about school physics that the time is ripe for
optics to be regained as a significant part of the school syllabus.
But before leaving the topic it would seem reasonable to try to answer the possible arguments
that might be cited against optics, in particular, the view that the topics I have discussed might
be regarded as too expensive or too complicated to be treated at school. I do not think this is the
case at all. I have spent a good part of my professional career developing methods of researching
and teaching in X-ray diffraction which circumvent the very complex mathematics that can be
involved. Optical analogue methods (see, for example, the Atlas of Optical Transforms 181 ) have
excited a great deal of interest simply because they do provide a relatively speedy visual way of
introducing the potential of X-ray diffraction to non-physicists without mathematics. And a large
part of the secret of their success is that they are visual. It is well known that diagrams and
photographs add enormously to the ease with which a difficult idea can be transmitted to listeners
or readers and, clearly, optics is the subject without equal for visual presentation.
A good deal of the teaching can be done with slides and photographs and they are certainly
not beyond the reach of schools. Lasers (%mW helium-neon) are now down in price to a level
that should enable a school to have one and the rewards are really considerable. There are several
bits of apparatus centred round a small laser now available. Image processing, for example, is easy
to demonstrate cheaply (e.g. Taylor [9]>. But we must not forget that Newton and Young and
others did experiments with simple pinholes, slits and prisms using sunlight and there is no
reason why this should not be repeated. Diffraction is easy to demonstrate by viewing a sodium
street light through an umbrella. Off-cuts of 1 cm thick plate glass as used for shop windows can
be acquired very cheaply from glaziers and are an excellent substitute for optical flats. My
earliest recollection of being fascinated by images was in accidentally seeing a pinhole image of
the world outside a cellar being used as a photographic darkroom. I suspect that this may be one
of the important clues to the re-introduction of optics as an exciting subject at school level.
Let us go beyond the old-fashioned ideas of image-seeking using pins, geometrical ray-tracing,
parallel-lined diffraction gratings, etc. and remember that optics is concerned with images of the
real, colourful world outside. I think the challenge of developing a course of school optics that is
exciting, is appealing to students who are not heading for science careers and which can give all
students a feeling for the relationships between science and everyday life is one that should be
taken up. I hope that perhaps this article' might encourage those who are already thinking along
these lines and perhaps even convert someone who has not yet begun. The resources available are
enormous and the likely rewards in terms of creating a genuine interest in physics and its relationships
to the world around us seem to me to be very considerable indeed.
REFERENCES
1. HousTOUN, R.A. A Treatise on Light. 1st ed. London, Longmans & Co., 1915.
2. ROBERTSON, J.K. Introduction to Physical Optics. 1st ed. New York, D. Van Nostrand Co., 1929.
3. NEWTON, Sir Isaac. 1704. Upticks. New York, Dover Publications, reprinted 1952.
1. I a m most grateful to Dr. G. Harburn for his helpful comments and criticisms on this paper.
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